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[PATCH openEuler-21.03 1/2] usb: cdns3: Fix runtime PM imbalance on error
by Zheng Zengkai 18 Aug '21

18 Aug '21

From: Dinghao Liu <dinghao.liu(a)zju.edu.cn> stable inclusion from stable-v5.10.44 commit 2f523cd4a9311cba629facc7d353eabbd492bd5b bugzilla: https://bugzilla.openeuler.org/show_bug.cgi?id=345 CVE: NA -------------------------------- [ Upstream commit 07adc0225484fc199e3dc15ec889f75f498c4fca ] When cdns3_gadget_start() fails, a pairing PM usage counter decrement is needed to keep the counter balanced. Signed-off-by: Dinghao Liu <dinghao.liu(a)zju.edu.cn> Link: https://lore.kernel.org/r/20210412054908.7975-1-dinghao.liu(a)zju.edu.cn Signed-off-by: Peter Chen <peter.chen(a)kernel.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> Signed-off-by: Xu Zehui <zehuixu(a)whu.edu.cn> Reviewed-by: Hanjun Guo <guohanjun(a)huawei.com> Signed-off-by: Zheng Zengkai <zhengzengkai(a)huawei.com> --- drivers/usb/cdns3/gadget.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/usb/cdns3/gadget.c b/drivers/usb/cdns3/gadget.c index 0aa85cc07ff1..c24c0e3440e3 100644 --- a/drivers/usb/cdns3/gadget.c +++ b/drivers/usb/cdns3/gadget.c @@ -3255,8 +3255,10 @@ static int __cdns3_gadget_init(struct cdns3 *cdns) pm_runtime_get_sync(cdns->dev); ret = cdns3_gadget_start(cdns); - if (ret) + if (ret) { + pm_runtime_put_sync(cdns->dev); return ret; + } /* * Because interrupt line can be shared with other components in -- 2.20.1

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[PATCH 9/9] kfence: add test suite
by 1415317271＠qq.com 18 Aug '21

18 Aug '21

From: Marco Elver <elver(a)google.com> Add KFENCE test suite, testing various error detection scenarios. Makes use of KUnit for test organization. Since KFENCE's interface to obtain error reports is via the console, the test verifies that KFENCE outputs expected reports to the console. [elver(a)google.com: fix typo in test] Link: https://lkml.kernel.org/r/X9lHQExmHGvETxY4@elver.google.com [elver(a)google.com: show access type in report] Link: https://lkml.kernel.org/r/20210111091544.3287013-2-elver@google.com Link: https://lkml.kernel.org/r/20201103175841.3495947-9-elver@google.com Signed-off-by: Alexander Potapenko <glider(a)google.com> Signed-off-by: Marco Elver <elver(a)google.com> Reviewed-by: Dmitry Vyukov <dvyukov(a)google.com> Co-developed-by: Alexander Potapenko <glider(a)google.com> Reviewed-by: Jann Horn <jannh(a)google.com> Cc: Andrey Konovalov <andreyknvl(a)google.com> Cc: Andrey Ryabinin <aryabinin(a)virtuozzo.com> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Catalin Marinas <catalin.marinas(a)arm.com> Cc: Christopher Lameter <cl(a)linux.com> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: David Rientjes <rientjes(a)google.com> Cc: Eric Dumazet <edumazet(a)google.com> Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Cc: Hillf Danton <hdanton(a)sina.com> Cc: "H. Peter Anvin" <hpa(a)zytor.com> Cc: Ingo Molnar <mingo(a)redhat.com> Cc: Joern Engel <joern(a)purestorage.com> Cc: Jonathan Corbet <corbet(a)lwn.net> Cc: Joonsoo Kim <iamjoonsoo.kim(a)lge.com> Cc: Kees Cook <keescook(a)chromium.org> Cc: Mark Rutland <mark.rutland(a)arm.com> Cc: Paul E. McKenney <paulmck(a)kernel.org> Cc: Pekka Enberg <penberg(a)kernel.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: SeongJae Park <sjpark(a)amazon.de> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: Will Deacon <will(a)kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds(a)linux-foundation.org> Signed-off-by: Yingjie Shang <1415317271(a)qq.com> Reviewed-by: Bixuan Cui <cuibixuan(a)huawei.com> --- Documentation/dev-tools/kfence.rst | 12 +- arch/arm64/mm/fault.c | 2 +- arch/x86/mm/fault.c | 3 +- include/linux/kfence.h | 9 +- lib/Kconfig.kfence | 13 + mm/kfence/Makefile | 3 + mm/kfence/core.c | 11 +- mm/kfence/kfence.h | 2 +- mm/kfence/kfence_test.c | 858 +++++++++++++++++++++++++++++ mm/kfence/report.c | 27 +- 10 files changed, 915 insertions(+), 25 deletions(-) create mode 100644 mm/kfence/kfence_test.c diff --git a/Documentation/dev-tools/kfence.rst b/Documentation/dev-tools/kfence.rst index 0e2fb6ef3016..58a0a5fa1ddc 100644 --- a/Documentation/dev-tools/kfence.rst +++ b/Documentation/dev-tools/kfence.rst @@ -65,9 +65,9 @@ Error reports A typical out-of-bounds access looks like this:: ================================================================== - BUG: KFENCE: out-of-bounds in test_out_of_bounds_read+0xa3/0x22b + BUG: KFENCE: out-of-bounds read in test_out_of_bounds_read+0xa3/0x22b - Out-of-bounds access at 0xffffffffb672efff (1B left of kfence-#17): + Out-of-bounds read at 0xffffffffb672efff (1B left of kfence-#17): test_out_of_bounds_read+0xa3/0x22b kunit_try_run_case+0x51/0x85 kunit_generic_run_threadfn_adapter+0x16/0x30 @@ -94,9 +94,9 @@ its origin. Note that, real kernel addresses are only shown for Use-after-free accesses are reported as:: ================================================================== - BUG: KFENCE: use-after-free in test_use_after_free_read+0xb3/0x143 + BUG: KFENCE: use-after-free read in test_use_after_free_read+0xb3/0x143 - Use-after-free access at 0xffffffffb673dfe0 (in kfence-#24): + Use-after-free read at 0xffffffffb673dfe0 (in kfence-#24): test_use_after_free_read+0xb3/0x143 kunit_try_run_case+0x51/0x85 kunit_generic_run_threadfn_adapter+0x16/0x30 @@ -193,9 +193,9 @@ where it was not possible to determine an associated object, e.g. if adjacent object pages had not yet been allocated:: ================================================================== - BUG: KFENCE: invalid access in test_invalid_access+0x26/0xe0 + BUG: KFENCE: invalid read in test_invalid_access+0x26/0xe0 - Invalid access at 0xffffffffb670b00a: + Invalid read at 0xffffffffb670b00a: test_invalid_access+0x26/0xe0 kunit_try_run_case+0x51/0x85 kunit_generic_run_threadfn_adapter+0x16/0x30 diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index a5fe9f7b423b..8f4ceab2fa35 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -323,7 +323,7 @@ static void __do_kernel_fault(unsigned long addr, unsigned int esr, } else if (addr < PAGE_SIZE) { msg = "NULL pointer dereference"; } else { - if (kfence_handle_page_fault(addr, regs)) + if (kfence_handle_page_fault(addr, esr & ESR_ELx_WNR, regs)) return; msg = "paging request"; diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index f5f359ccaeae..738985c131ea 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -734,7 +734,8 @@ no_context(struct pt_regs *regs, unsigned long error_code, efi_recover_from_page_fault(address); /* Only not-present faults should be handled by KFENCE. */ - if (!(error_code & X86_PF_PROT) && kfence_handle_page_fault(address, regs)) + if (!(error_code & X86_PF_PROT) && + kfence_handle_page_fault(address, error_code & X86_PF_WRITE, regs)) return; oops: /* diff --git a/include/linux/kfence.h b/include/linux/kfence.h index 5a56bcf5606c..a70d1ea03532 100644 --- a/include/linux/kfence.h +++ b/include/linux/kfence.h @@ -186,6 +186,7 @@ static __always_inline __must_check bool kfence_free(void *addr) /** * kfence_handle_page_fault() - perform page fault handling for KFENCE pages * @addr: faulting address + * @is_write: is access a write * @regs: current struct pt_regs (can be NULL, but shows full stack trace) * * Return: @@ -197,7 +198,7 @@ static __always_inline __must_check bool kfence_free(void *addr) * cases KFENCE prints an error message and marks the offending page as * present, so that the kernel can proceed. */ -bool __must_check kfence_handle_page_fault(unsigned long addr, struct pt_regs *regs); +bool __must_check kfence_handle_page_fault(unsigned long addr, bool is_write, struct pt_regs *regs); #else /* CONFIG_KFENCE */ @@ -210,7 +211,11 @@ static inline size_t kfence_ksize(const void *addr) { return 0; } static inline void *kfence_object_start(const void *addr) { return NULL; } static inline void __kfence_free(void *addr) { } static inline bool __must_check kfence_free(void *addr) { return false; } -static inline bool __must_check kfence_handle_page_fault(unsigned long addr, struct pt_regs *regs) { return false; } +static inline bool __must_check kfence_handle_page_fault(unsigned long addr, bool is_write, + struct pt_regs *regs) +{ + return false; +} #endif diff --git a/lib/Kconfig.kfence b/lib/Kconfig.kfence index 605125ac2ae0..78f50ccb3b45 100644 --- a/lib/Kconfig.kfence +++ b/lib/Kconfig.kfence @@ -66,4 +66,17 @@ config KFENCE_STRESS_TEST_FAULTS Only for KFENCE testing; set to 0 if you are not a KFENCE developer. +config KFENCE_KUNIT_TEST + tristate "KFENCE integration test suite" if !KUNIT_ALL_TESTS + default KUNIT_ALL_TESTS + depends on TRACEPOINTS && KUNIT + help + Test suite for KFENCE, testing various error detection scenarios with + various allocation types, and checking that reports are correctly + output to console. + + Say Y here if you want the test to be built into the kernel and run + during boot; say M if you want the test to build as a module; say N + if you are unsure. + endif # KFENCE diff --git a/mm/kfence/Makefile b/mm/kfence/Makefile index d991e9a349f0..6872cd5e5390 100644 --- a/mm/kfence/Makefile +++ b/mm/kfence/Makefile @@ -1,3 +1,6 @@ # SPDX-License-Identifier: GPL-2.0 obj-$(CONFIG_KFENCE) := core.o report.o + +CFLAGS_kfence_test.o := -g -fno-omit-frame-pointer -fno-optimize-sibling-calls +obj-$(CONFIG_KFENCE_KUNIT_TEST) += kfence_test.o diff --git a/mm/kfence/core.c b/mm/kfence/core.c index 7692af715fdb..cfe3d32ac5b7 100644 --- a/mm/kfence/core.c +++ b/mm/kfence/core.c @@ -216,7 +216,7 @@ static inline bool check_canary_byte(u8 *addr) return true; atomic_long_inc(&counters[KFENCE_COUNTER_BUGS]); - kfence_report_error((unsigned long)addr, NULL, addr_to_metadata((unsigned long)addr), + kfence_report_error((unsigned long)addr, false, NULL, addr_to_metadata((unsigned long)addr), KFENCE_ERROR_CORRUPTION); return false; } @@ -355,7 +355,8 @@ static void kfence_guarded_free(void *addr, struct kfence_metadata *meta, bool z if (meta->state != KFENCE_OBJECT_ALLOCATED || meta->addr != (unsigned long)addr) { /* Invalid or double-free, bail out. */ atomic_long_inc(&counters[KFENCE_COUNTER_BUGS]); - kfence_report_error((unsigned long)addr, NULL, meta, KFENCE_ERROR_INVALID_FREE); + kfence_report_error((unsigned long)addr, false, NULL, meta, + KFENCE_ERROR_INVALID_FREE); raw_spin_unlock_irqrestore(&meta->lock, flags); return; } @@ -770,7 +771,7 @@ void __kfence_free(void *addr) kfence_guarded_free(addr, meta, false); } -bool kfence_handle_page_fault(unsigned long addr, struct pt_regs *regs) +bool kfence_handle_page_fault(unsigned long addr, bool is_write, struct pt_regs *regs) { const int page_index = (addr - (unsigned long)__kfence_pool) / PAGE_SIZE; struct kfence_metadata *to_report = NULL; @@ -833,11 +834,11 @@ bool kfence_handle_page_fault(unsigned long addr, struct pt_regs *regs) out: if (to_report) { - kfence_report_error(addr, regs, to_report, error_type); + kfence_report_error(addr, is_write, regs, to_report, error_type); raw_spin_unlock_irqrestore(&to_report->lock, flags); } else { /* This may be a UAF or OOB access, but we can't be sure. */ - kfence_report_error(addr, regs, NULL, KFENCE_ERROR_INVALID); + kfence_report_error(addr, is_write, regs, NULL, KFENCE_ERROR_INVALID); } return kfence_unprotect(addr); /* Unprotect and let access proceed. */ diff --git a/mm/kfence/kfence.h b/mm/kfence/kfence.h index 0d83e628a97d..1accc840dbbe 100644 --- a/mm/kfence/kfence.h +++ b/mm/kfence/kfence.h @@ -105,7 +105,7 @@ enum kfence_error_type { KFENCE_ERROR_INVALID_FREE, /* Invalid free. */ }; -void kfence_report_error(unsigned long address, struct pt_regs *regs, +void kfence_report_error(unsigned long address, bool is_write, struct pt_regs *regs, const struct kfence_metadata *meta, enum kfence_error_type type); void kfence_print_object(struct seq_file *seq, const struct kfence_metadata *meta); diff --git a/mm/kfence/kfence_test.c b/mm/kfence/kfence_test.c new file mode 100644 index 000000000000..db1bb596acaf --- /dev/null +++ b/mm/kfence/kfence_test.c @@ -0,0 +1,858 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Test cases for KFENCE memory safety error detector. Since the interface with + * which KFENCE's reports are obtained is via the console, this is the output we + * should verify. For each test case checks the presence (or absence) of + * generated reports. Relies on 'console' tracepoint to capture reports as they + * appear in the kernel log. + * + * Copyright (C) 2020, Google LLC. + * Author: Alexander Potapenko <glider(a)google.com> + * Marco Elver <elver(a)google.com> + */ + +#include <kunit/test.h> +#include <linux/jiffies.h> +#include <linux/kernel.h> +#include <linux/kfence.h> +#include <linux/mm.h> +#include <linux/random.h> +#include <linux/slab.h> +#include <linux/spinlock.h> +#include <linux/string.h> +#include <linux/tracepoint.h> +#include <trace/events/printk.h> + +#include "kfence.h" + +/* Report as observed from console. */ +static struct { + spinlock_t lock; + int nlines; + char lines[2][256]; +} observed = { + .lock = __SPIN_LOCK_UNLOCKED(observed.lock), +}; + +/* Probe for console output: obtains observed lines of interest. */ +static void probe_console(void *ignore, const char *buf, size_t len) +{ + unsigned long flags; + int nlines; + + spin_lock_irqsave(&observed.lock, flags); + nlines = observed.nlines; + + if (strnstr(buf, "BUG: KFENCE: ", len) && strnstr(buf, "test_", len)) { + /* + * KFENCE report and related to the test. + * + * The provided @buf is not NUL-terminated; copy no more than + * @len bytes and let strscpy() add the missing NUL-terminator. + */ + strscpy(observed.lines[0], buf, min(len + 1, sizeof(observed.lines[0]))); + nlines = 1; + } else if (nlines == 1 && (strnstr(buf, "at 0x", len) || strnstr(buf, "of 0x", len))) { + strscpy(observed.lines[nlines++], buf, min(len + 1, sizeof(observed.lines[0]))); + } + + WRITE_ONCE(observed.nlines, nlines); /* Publish new nlines. */ + spin_unlock_irqrestore(&observed.lock, flags); +} + +/* Check if a report related to the test exists. */ +static bool report_available(void) +{ + return READ_ONCE(observed.nlines) == ARRAY_SIZE(observed.lines); +} + +/* Information we expect in a report. */ +struct expect_report { + enum kfence_error_type type; /* The type or error. */ + void *fn; /* Function pointer to expected function where access occurred. */ + char *addr; /* Address at which the bad access occurred. */ + bool is_write; /* Is access a write. */ +}; + +static const char *get_access_type(const struct expect_report *r) +{ + return r->is_write ? "write" : "read"; +} + +/* Check observed report matches information in @r. */ +static bool report_matches(const struct expect_report *r) +{ + bool ret = false; + unsigned long flags; + typeof(observed.lines) expect; + const char *end; + char *cur; + + /* Doubled-checked locking. */ + if (!report_available()) + return false; + + /* Generate expected report contents. */ + + /* Title */ + cur = expect[0]; + end = &expect[0][sizeof(expect[0]) - 1]; + switch (r->type) { + case KFENCE_ERROR_OOB: + cur += scnprintf(cur, end - cur, "BUG: KFENCE: out-of-bounds %s", + get_access_type(r)); + break; + case KFENCE_ERROR_UAF: + cur += scnprintf(cur, end - cur, "BUG: KFENCE: use-after-free %s", + get_access_type(r)); + break; + case KFENCE_ERROR_CORRUPTION: + cur += scnprintf(cur, end - cur, "BUG: KFENCE: memory corruption"); + break; + case KFENCE_ERROR_INVALID: + cur += scnprintf(cur, end - cur, "BUG: KFENCE: invalid %s", + get_access_type(r)); + break; + case KFENCE_ERROR_INVALID_FREE: + cur += scnprintf(cur, end - cur, "BUG: KFENCE: invalid free"); + break; + } + + scnprintf(cur, end - cur, " in %pS", r->fn); + /* The exact offset won't match, remove it; also strip module name. */ + cur = strchr(expect[0], '+'); + if (cur) + *cur = '\0'; + + /* Access information */ + cur = expect[1]; + end = &expect[1][sizeof(expect[1]) - 1]; + + switch (r->type) { + case KFENCE_ERROR_OOB: + cur += scnprintf(cur, end - cur, "Out-of-bounds %s at", get_access_type(r)); + break; + case KFENCE_ERROR_UAF: + cur += scnprintf(cur, end - cur, "Use-after-free %s at", get_access_type(r)); + break; + case KFENCE_ERROR_CORRUPTION: + cur += scnprintf(cur, end - cur, "Corrupted memory at"); + break; + case KFENCE_ERROR_INVALID: + cur += scnprintf(cur, end - cur, "Invalid %s at", get_access_type(r)); + break; + case KFENCE_ERROR_INVALID_FREE: + cur += scnprintf(cur, end - cur, "Invalid free of"); + break; + } + + cur += scnprintf(cur, end - cur, " 0x" PTR_FMT, (void *)r->addr); + + spin_lock_irqsave(&observed.lock, flags); + if (!report_available()) + goto out; /* A new report is being captured. */ + + /* Finally match expected output to what we actually observed. */ + ret = strstr(observed.lines[0], expect[0]) && strstr(observed.lines[1], expect[1]); +out: + spin_unlock_irqrestore(&observed.lock, flags); + return ret; +} + +/* ===== Test cases ===== */ + +#define TEST_PRIV_WANT_MEMCACHE ((void *)1) + +/* Cache used by tests; if NULL, allocate from kmalloc instead. */ +static struct kmem_cache *test_cache; + +static size_t setup_test_cache(struct kunit *test, size_t size, slab_flags_t flags, + void (*ctor)(void *)) +{ + if (test->priv != TEST_PRIV_WANT_MEMCACHE) + return size; + + kunit_info(test, "%s: size=%zu, ctor=%ps\n", __func__, size, ctor); + + /* + * Use SLAB_NOLEAKTRACE to prevent merging with existing caches. Any + * other flag in SLAB_NEVER_MERGE also works. Use SLAB_ACCOUNT to + * allocate via memcg, if enabled. + */ + flags |= SLAB_NOLEAKTRACE | SLAB_ACCOUNT; + test_cache = kmem_cache_create("test", size, 1, flags, ctor); + KUNIT_ASSERT_TRUE_MSG(test, test_cache, "could not create cache"); + + return size; +} + +static void test_cache_destroy(void) +{ + if (!test_cache) + return; + + kmem_cache_destroy(test_cache); + test_cache = NULL; +} + +static inline size_t kmalloc_cache_alignment(size_t size) +{ + return kmalloc_caches[kmalloc_type(GFP_KERNEL)][kmalloc_index(size)]->align; +} + +/* Must always inline to match stack trace against caller. */ +static __always_inline void test_free(void *ptr) +{ + if (test_cache) + kmem_cache_free(test_cache, ptr); + else + kfree(ptr); +} + +/* + * If this should be a KFENCE allocation, and on which side the allocation and + * the closest guard page should be. + */ +enum allocation_policy { + ALLOCATE_ANY, /* KFENCE, any side. */ + ALLOCATE_LEFT, /* KFENCE, left side of page. */ + ALLOCATE_RIGHT, /* KFENCE, right side of page. */ + ALLOCATE_NONE, /* No KFENCE allocation. */ +}; + +/* + * Try to get a guarded allocation from KFENCE. Uses either kmalloc() or the + * current test_cache if set up. + */ +static void *test_alloc(struct kunit *test, size_t size, gfp_t gfp, enum allocation_policy policy) +{ + void *alloc; + unsigned long timeout, resched_after; + const char *policy_name; + + switch (policy) { + case ALLOCATE_ANY: + policy_name = "any"; + break; + case ALLOCATE_LEFT: + policy_name = "left"; + break; + case ALLOCATE_RIGHT: + policy_name = "right"; + break; + case ALLOCATE_NONE: + policy_name = "none"; + break; + } + + kunit_info(test, "%s: size=%zu, gfp=%x, policy=%s, cache=%i\n", __func__, size, gfp, + policy_name, !!test_cache); + + /* + * 100x the sample interval should be more than enough to ensure we get + * a KFENCE allocation eventually. + */ + timeout = jiffies + msecs_to_jiffies(100 * CONFIG_KFENCE_SAMPLE_INTERVAL); + /* + * Especially for non-preemption kernels, ensure the allocation-gate + * timer can catch up: after @resched_after, every failed allocation + * attempt yields, to ensure the allocation-gate timer is scheduled. + */ + resched_after = jiffies + msecs_to_jiffies(CONFIG_KFENCE_SAMPLE_INTERVAL); + do { + if (test_cache) + alloc = kmem_cache_alloc(test_cache, gfp); + else + alloc = kmalloc(size, gfp); + + if (is_kfence_address(alloc)) { + struct page *page = virt_to_head_page(alloc); + struct kmem_cache *s = test_cache ?: kmalloc_caches[kmalloc_type(GFP_KERNEL)][kmalloc_index(size)]; + + /* + * Verify that various helpers return the right values + * even for KFENCE objects; these are required so that + * memcg accounting works correctly. + */ + KUNIT_EXPECT_EQ(test, obj_to_index(s, page, alloc), 0U); + KUNIT_EXPECT_EQ(test, objs_per_slab_page(s, page), 1); + + if (policy == ALLOCATE_ANY) + return alloc; + if (policy == ALLOCATE_LEFT && IS_ALIGNED((unsigned long)alloc, PAGE_SIZE)) + return alloc; + if (policy == ALLOCATE_RIGHT && + !IS_ALIGNED((unsigned long)alloc, PAGE_SIZE)) + return alloc; + } else if (policy == ALLOCATE_NONE) + return alloc; + + test_free(alloc); + + if (time_after(jiffies, resched_after)) + cond_resched(); + } while (time_before(jiffies, timeout)); + + KUNIT_ASSERT_TRUE_MSG(test, false, "failed to allocate from KFENCE"); + return NULL; /* Unreachable. */ +} + +static void test_out_of_bounds_read(struct kunit *test) +{ + size_t size = 32; + struct expect_report expect = { + .type = KFENCE_ERROR_OOB, + .fn = test_out_of_bounds_read, + .is_write = false, + }; + char *buf; + + setup_test_cache(test, size, 0, NULL); + + /* + * If we don't have our own cache, adjust based on alignment, so that we + * actually access guard pages on either side. + */ + if (!test_cache) + size = kmalloc_cache_alignment(size); + + /* Test both sides. */ + + buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_LEFT); + expect.addr = buf - 1; + READ_ONCE(*expect.addr); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); + test_free(buf); + + buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_RIGHT); + expect.addr = buf + size; + READ_ONCE(*expect.addr); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); + test_free(buf); +} + +static void test_out_of_bounds_write(struct kunit *test) +{ + size_t size = 32; + struct expect_report expect = { + .type = KFENCE_ERROR_OOB, + .fn = test_out_of_bounds_write, + .is_write = true, + }; + char *buf; + + setup_test_cache(test, size, 0, NULL); + buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_LEFT); + expect.addr = buf - 1; + WRITE_ONCE(*expect.addr, 42); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); + test_free(buf); +} + +static void test_use_after_free_read(struct kunit *test) +{ + const size_t size = 32; + struct expect_report expect = { + .type = KFENCE_ERROR_UAF, + .fn = test_use_after_free_read, + .is_write = false, + }; + + setup_test_cache(test, size, 0, NULL); + expect.addr = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY); + test_free(expect.addr); + READ_ONCE(*expect.addr); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +static void test_double_free(struct kunit *test) +{ + const size_t size = 32; + struct expect_report expect = { + .type = KFENCE_ERROR_INVALID_FREE, + .fn = test_double_free, + }; + + setup_test_cache(test, size, 0, NULL); + expect.addr = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY); + test_free(expect.addr); + test_free(expect.addr); /* Double-free. */ + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +static void test_invalid_addr_free(struct kunit *test) +{ + const size_t size = 32; + struct expect_report expect = { + .type = KFENCE_ERROR_INVALID_FREE, + .fn = test_invalid_addr_free, + }; + char *buf; + + setup_test_cache(test, size, 0, NULL); + buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY); + expect.addr = buf + 1; /* Free on invalid address. */ + test_free(expect.addr); /* Invalid address free. */ + test_free(buf); /* No error. */ + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +static void test_corruption(struct kunit *test) +{ + size_t size = 32; + struct expect_report expect = { + .type = KFENCE_ERROR_CORRUPTION, + .fn = test_corruption, + }; + char *buf; + + setup_test_cache(test, size, 0, NULL); + + /* Test both sides. */ + + buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_LEFT); + expect.addr = buf + size; + WRITE_ONCE(*expect.addr, 42); + test_free(buf); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); + + buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_RIGHT); + expect.addr = buf - 1; + WRITE_ONCE(*expect.addr, 42); + test_free(buf); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +/* + * KFENCE is unable to detect an OOB if the allocation's alignment requirements + * leave a gap between the object and the guard page. Specifically, an + * allocation of e.g. 73 bytes is aligned on 8 and 128 bytes for SLUB or SLAB + * respectively. Therefore it is impossible for the allocated object to + * contiguously line up with the right guard page. + * + * However, we test that an access to memory beyond the gap results in KFENCE + * detecting an OOB access. + */ +static void test_kmalloc_aligned_oob_read(struct kunit *test) +{ + const size_t size = 73; + const size_t align = kmalloc_cache_alignment(size); + struct expect_report expect = { + .type = KFENCE_ERROR_OOB, + .fn = test_kmalloc_aligned_oob_read, + .is_write = false, + }; + char *buf; + + buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_RIGHT); + + /* + * The object is offset to the right, so there won't be an OOB to the + * left of it. + */ + READ_ONCE(*(buf - 1)); + KUNIT_EXPECT_FALSE(test, report_available()); + + /* + * @buf must be aligned on @align, therefore buf + size belongs to the + * same page -> no OOB. + */ + READ_ONCE(*(buf + size)); + KUNIT_EXPECT_FALSE(test, report_available()); + + /* Overflowing by @align bytes will result in an OOB. */ + expect.addr = buf + size + align; + READ_ONCE(*expect.addr); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); + + test_free(buf); +} + +static void test_kmalloc_aligned_oob_write(struct kunit *test) +{ + const size_t size = 73; + struct expect_report expect = { + .type = KFENCE_ERROR_CORRUPTION, + .fn = test_kmalloc_aligned_oob_write, + }; + char *buf; + + buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_RIGHT); + /* + * The object is offset to the right, so we won't get a page + * fault immediately after it. + */ + expect.addr = buf + size; + WRITE_ONCE(*expect.addr, READ_ONCE(*expect.addr) + 1); + KUNIT_EXPECT_FALSE(test, report_available()); + test_free(buf); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +/* Test cache shrinking and destroying with KFENCE. */ +static void test_shrink_memcache(struct kunit *test) +{ + const size_t size = 32; + void *buf; + + setup_test_cache(test, size, 0, NULL); + KUNIT_EXPECT_TRUE(test, test_cache); + buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY); + kmem_cache_shrink(test_cache); + test_free(buf); + + KUNIT_EXPECT_FALSE(test, report_available()); +} + +static void ctor_set_x(void *obj) +{ + /* Every object has at least 8 bytes. */ + memset(obj, 'x', 8); +} + +/* Ensure that SL*B does not modify KFENCE objects on bulk free. */ +static void test_free_bulk(struct kunit *test) +{ + int iter; + + for (iter = 0; iter < 5; iter++) { + const size_t size = setup_test_cache(test, 8 + prandom_u32_max(300), 0, + (iter & 1) ? ctor_set_x : NULL); + void *objects[] = { + test_alloc(test, size, GFP_KERNEL, ALLOCATE_RIGHT), + test_alloc(test, size, GFP_KERNEL, ALLOCATE_NONE), + test_alloc(test, size, GFP_KERNEL, ALLOCATE_LEFT), + test_alloc(test, size, GFP_KERNEL, ALLOCATE_NONE), + test_alloc(test, size, GFP_KERNEL, ALLOCATE_NONE), + }; + + kmem_cache_free_bulk(test_cache, ARRAY_SIZE(objects), objects); + KUNIT_ASSERT_FALSE(test, report_available()); + test_cache_destroy(); + } +} + +/* Test init-on-free works. */ +static void test_init_on_free(struct kunit *test) +{ + const size_t size = 32; + struct expect_report expect = { + .type = KFENCE_ERROR_UAF, + .fn = test_init_on_free, + .is_write = false, + }; + int i; + + if (!IS_ENABLED(CONFIG_INIT_ON_FREE_DEFAULT_ON)) + return; + /* Assume it hasn't been disabled on command line. */ + + setup_test_cache(test, size, 0, NULL); + expect.addr = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY); + for (i = 0; i < size; i++) + expect.addr[i] = i + 1; + test_free(expect.addr); + + for (i = 0; i < size; i++) { + /* + * This may fail if the page was recycled by KFENCE and then + * written to again -- this however, is near impossible with a + * default config. + */ + KUNIT_EXPECT_EQ(test, expect.addr[i], (char)0); + + if (!i) /* Only check first access to not fail test if page is ever re-protected. */ + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); + } +} + +/* Ensure that constructors work properly. */ +static void test_memcache_ctor(struct kunit *test) +{ + const size_t size = 32; + char *buf; + int i; + + setup_test_cache(test, size, 0, ctor_set_x); + buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY); + + for (i = 0; i < 8; i++) + KUNIT_EXPECT_EQ(test, buf[i], (char)'x'); + + test_free(buf); + + KUNIT_EXPECT_FALSE(test, report_available()); +} + +/* Test that memory is zeroed if requested. */ +static void test_gfpzero(struct kunit *test) +{ + const size_t size = PAGE_SIZE; /* PAGE_SIZE so we can use ALLOCATE_ANY. */ + char *buf1, *buf2; + int i; + + if (CONFIG_KFENCE_SAMPLE_INTERVAL > 100) { + kunit_warn(test, "skipping ... would take too long\n"); + return; + } + + setup_test_cache(test, size, 0, NULL); + buf1 = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY); + for (i = 0; i < size; i++) + buf1[i] = i + 1; + test_free(buf1); + + /* Try to get same address again -- this can take a while. */ + for (i = 0;; i++) { + buf2 = test_alloc(test, size, GFP_KERNEL | __GFP_ZERO, ALLOCATE_ANY); + if (buf1 == buf2) + break; + test_free(buf2); + + if (i == CONFIG_KFENCE_NUM_OBJECTS) { + kunit_warn(test, "giving up ... cannot get same object back\n"); + return; + } + } + + for (i = 0; i < size; i++) + KUNIT_EXPECT_EQ(test, buf2[i], (char)0); + + test_free(buf2); + + KUNIT_EXPECT_FALSE(test, report_available()); +} + +static void test_invalid_access(struct kunit *test) +{ + const struct expect_report expect = { + .type = KFENCE_ERROR_INVALID, + .fn = test_invalid_access, + .addr = &__kfence_pool[10], + .is_write = false, + }; + + READ_ONCE(__kfence_pool[10]); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +/* Test SLAB_TYPESAFE_BY_RCU works. */ +static void test_memcache_typesafe_by_rcu(struct kunit *test) +{ + const size_t size = 32; + struct expect_report expect = { + .type = KFENCE_ERROR_UAF, + .fn = test_memcache_typesafe_by_rcu, + .is_write = false, + }; + + setup_test_cache(test, size, SLAB_TYPESAFE_BY_RCU, NULL); + KUNIT_EXPECT_TRUE(test, test_cache); /* Want memcache. */ + + expect.addr = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY); + *expect.addr = 42; + + rcu_read_lock(); + test_free(expect.addr); + KUNIT_EXPECT_EQ(test, *expect.addr, (char)42); + /* + * Up to this point, memory should not have been freed yet, and + * therefore there should be no KFENCE report from the above access. + */ + rcu_read_unlock(); + + /* Above access to @expect.addr should not have generated a report! */ + KUNIT_EXPECT_FALSE(test, report_available()); + + /* Only after rcu_barrier() is the memory guaranteed to be freed. */ + rcu_barrier(); + + /* Expect use-after-free. */ + KUNIT_EXPECT_EQ(test, *expect.addr, (char)42); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +/* Test krealloc(). */ +static void test_krealloc(struct kunit *test) +{ + const size_t size = 32; + const struct expect_report expect = { + .type = KFENCE_ERROR_UAF, + .fn = test_krealloc, + .addr = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY), + .is_write = false, + }; + char *buf = expect.addr; + int i; + + KUNIT_EXPECT_FALSE(test, test_cache); + KUNIT_EXPECT_EQ(test, ksize(buf), size); /* Precise size match after KFENCE alloc. */ + for (i = 0; i < size; i++) + buf[i] = i + 1; + + /* Check that we successfully change the size. */ + buf = krealloc(buf, size * 3, GFP_KERNEL); /* Grow. */ + /* Note: Might no longer be a KFENCE alloc. */ + KUNIT_EXPECT_GE(test, ksize(buf), size * 3); + for (i = 0; i < size; i++) + KUNIT_EXPECT_EQ(test, buf[i], (char)(i + 1)); + for (; i < size * 3; i++) /* Fill to extra bytes. */ + buf[i] = i + 1; + + buf = krealloc(buf, size * 2, GFP_KERNEL); /* Shrink. */ + KUNIT_EXPECT_GE(test, ksize(buf), size * 2); + for (i = 0; i < size * 2; i++) + KUNIT_EXPECT_EQ(test, buf[i], (char)(i + 1)); + + buf = krealloc(buf, 0, GFP_KERNEL); /* Free. */ + KUNIT_EXPECT_EQ(test, (unsigned long)buf, (unsigned long)ZERO_SIZE_PTR); + KUNIT_ASSERT_FALSE(test, report_available()); /* No reports yet! */ + + READ_ONCE(*expect.addr); /* Ensure krealloc() actually freed earlier KFENCE object. */ + KUNIT_ASSERT_TRUE(test, report_matches(&expect)); +} + +/* Test that some objects from a bulk allocation belong to KFENCE pool. */ +static void test_memcache_alloc_bulk(struct kunit *test) +{ + const size_t size = 32; + bool pass = false; + unsigned long timeout; + + setup_test_cache(test, size, 0, NULL); + KUNIT_EXPECT_TRUE(test, test_cache); /* Want memcache. */ + /* + * 100x the sample interval should be more than enough to ensure we get + * a KFENCE allocation eventually. + */ + timeout = jiffies + msecs_to_jiffies(100 * CONFIG_KFENCE_SAMPLE_INTERVAL); + do { + void *objects[100]; + int i, num = kmem_cache_alloc_bulk(test_cache, GFP_ATOMIC, ARRAY_SIZE(objects), + objects); + if (!num) + continue; + for (i = 0; i < ARRAY_SIZE(objects); i++) { + if (is_kfence_address(objects[i])) { + pass = true; + break; + } + } + kmem_cache_free_bulk(test_cache, num, objects); + /* + * kmem_cache_alloc_bulk() disables interrupts, and calling it + * in a tight loop may not give KFENCE a chance to switch the + * static branch. Call cond_resched() to let KFENCE chime in. + */ + cond_resched(); + } while (!pass && time_before(jiffies, timeout)); + + KUNIT_EXPECT_TRUE(test, pass); + KUNIT_EXPECT_FALSE(test, report_available()); +} + +/* + * KUnit does not provide a way to provide arguments to tests, and we encode + * additional info in the name. Set up 2 tests per test case, one using the + * default allocator, and another using a custom memcache (suffix '-memcache'). + */ +#define KFENCE_KUNIT_CASE(test_name) \ + { .run_case = test_name, .name = #test_name }, \ + { .run_case = test_name, .name = #test_name "-memcache" } + +static struct kunit_case kfence_test_cases[] = { + KFENCE_KUNIT_CASE(test_out_of_bounds_read), + KFENCE_KUNIT_CASE(test_out_of_bounds_write), + KFENCE_KUNIT_CASE(test_use_after_free_read), + KFENCE_KUNIT_CASE(test_double_free), + KFENCE_KUNIT_CASE(test_invalid_addr_free), + KFENCE_KUNIT_CASE(test_corruption), + KFENCE_KUNIT_CASE(test_free_bulk), + KFENCE_KUNIT_CASE(test_init_on_free), + KUNIT_CASE(test_kmalloc_aligned_oob_read), + KUNIT_CASE(test_kmalloc_aligned_oob_write), + KUNIT_CASE(test_shrink_memcache), + KUNIT_CASE(test_memcache_ctor), + KUNIT_CASE(test_invalid_access), + KUNIT_CASE(test_gfpzero), + KUNIT_CASE(test_memcache_typesafe_by_rcu), + KUNIT_CASE(test_krealloc), + KUNIT_CASE(test_memcache_alloc_bulk), + {}, +}; + +/* ===== End test cases ===== */ + +static int test_init(struct kunit *test) +{ + unsigned long flags; + int i; + + spin_lock_irqsave(&observed.lock, flags); + for (i = 0; i < ARRAY_SIZE(observed.lines); i++) + observed.lines[i][0] = '\0'; + observed.nlines = 0; + spin_unlock_irqrestore(&observed.lock, flags); + + /* Any test with 'memcache' in its name will want a memcache. */ + if (strstr(test->name, "memcache")) + test->priv = TEST_PRIV_WANT_MEMCACHE; + else + test->priv = NULL; + + return 0; +} + +static void test_exit(struct kunit *test) +{ + test_cache_destroy(); +} + +static struct kunit_suite kfence_test_suite = { + .name = "kfence", + .test_cases = kfence_test_cases, + .init = test_init, + .exit = test_exit, +}; +static struct kunit_suite *kfence_test_suites[] = { &kfence_test_suite, NULL }; + +static void register_tracepoints(struct tracepoint *tp, void *ignore) +{ + check_trace_callback_type_console(probe_console); + if (!strcmp(tp->name, "console")) + WARN_ON(tracepoint_probe_register(tp, probe_console, NULL)); +} + +static void unregister_tracepoints(struct tracepoint *tp, void *ignore) +{ + if (!strcmp(tp->name, "console")) + tracepoint_probe_unregister(tp, probe_console, NULL); +} + +/* + * We only want to do tracepoints setup and teardown once, therefore we have to + * customize the init and exit functions and cannot rely on kunit_test_suite(). + */ +static int __init kfence_test_init(void) +{ + /* + * Because we want to be able to build the test as a module, we need to + * iterate through all known tracepoints, since the static registration + * won't work here. + */ + for_each_kernel_tracepoint(register_tracepoints, NULL); + return __kunit_test_suites_init(kfence_test_suites); +} + +static void kfence_test_exit(void) +{ + __kunit_test_suites_exit(kfence_test_suites); + for_each_kernel_tracepoint(unregister_tracepoints, NULL); + tracepoint_synchronize_unregister(); +} + +late_initcall(kfence_test_init); +module_exit(kfence_test_exit); + +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Alexander Potapenko <glider(a)google.com>, Marco Elver <elver(a)google.com>"); diff --git a/mm/kfence/report.c b/mm/kfence/report.c index 4dbfa9a382e4..901bd7ee83d8 100644 --- a/mm/kfence/report.c +++ b/mm/kfence/report.c @@ -156,7 +156,12 @@ static void print_diff_canary(unsigned long address, size_t bytes_to_show, pr_cont(" ]"); } -void kfence_report_error(unsigned long address, struct pt_regs *regs, +static const char *get_access_type(bool is_write) +{ + return is_write ? "write" : "read"; +} + +void kfence_report_error(unsigned long address, bool is_write, struct pt_regs *regs, const struct kfence_metadata *meta, enum kfence_error_type type) { unsigned long stack_entries[KFENCE_STACK_DEPTH] = { 0 }; @@ -194,17 +199,19 @@ void kfence_report_error(unsigned long address, struct pt_regs *regs, case KFENCE_ERROR_OOB: { const bool left_of_object = address < meta->addr; - pr_err("BUG: KFENCE: out-of-bounds in %pS\n\n", (void *)stack_entries[skipnr]); - pr_err("Out-of-bounds access at 0x" PTR_FMT " (%luB %s of kfence-#%zd):\n", - (void *)address, + pr_err("BUG: KFENCE: out-of-bounds %s in %pS\n\n", get_access_type(is_write), + (void *)stack_entries[skipnr]); + pr_err("Out-of-bounds %s at 0x" PTR_FMT " (%luB %s of kfence-#%zd):\n", + get_access_type(is_write), (void *)address, left_of_object ? meta->addr - address : address - meta->addr, left_of_object ? "left" : "right", object_index); break; } case KFENCE_ERROR_UAF: - pr_err("BUG: KFENCE: use-after-free in %pS\n\n", (void *)stack_entries[skipnr]); - pr_err("Use-after-free access at 0x" PTR_FMT " (in kfence-#%zd):\n", - (void *)address, object_index); + pr_err("BUG: KFENCE: use-after-free %s in %pS\n\n", get_access_type(is_write), + (void *)stack_entries[skipnr]); + pr_err("Use-after-free %s at 0x" PTR_FMT " (in kfence-#%zd):\n", + get_access_type(is_write), (void *)address, object_index); break; case KFENCE_ERROR_CORRUPTION: pr_err("BUG: KFENCE: memory corruption in %pS\n\n", (void *)stack_entries[skipnr]); @@ -213,8 +220,10 @@ void kfence_report_error(unsigned long address, struct pt_regs *regs, pr_cont(" (in kfence-#%zd):\n", object_index); break; case KFENCE_ERROR_INVALID: - pr_err("BUG: KFENCE: invalid access in %pS\n\n", (void *)stack_entries[skipnr]); - pr_err("Invalid access at 0x" PTR_FMT ":\n", (void *)address); + pr_err("BUG: KFENCE: invalid %s in %pS\n\n", get_access_type(is_write), + (void *)stack_entries[skipnr]); + pr_err("Invalid %s at 0x" PTR_FMT ":\n", get_access_type(is_write), + (void *)address); break; case KFENCE_ERROR_INVALID_FREE: pr_err("BUG: KFENCE: invalid free in %pS\n\n", (void *)stack_entries[skipnr]); -- 2.25.1

1 0

[PATCH 8/9] kfence, Documentation: add KFENCE documentation
by 1415317271＠qq.com 18 Aug '21

18 Aug '21

From: Marco Elver <elver(a)google.com> Add KFENCE documentation in dev-tools/kfence.rst, and add to index. [elver(a)google.com: add missing copyright header to documentation] Link: https://lkml.kernel.org/r/20210118092159.145934-4-elver@google.com Link: https://lkml.kernel.org/r/20201103175841.3495947-8-elver@google.com Signed-off-by: Alexander Potapenko <glider(a)google.com> Signed-off-by: Marco Elver <elver(a)google.com> Reviewed-by: Dmitry Vyukov <dvyukov(a)google.com> Co-developed-by: Alexander Potapenko <glider(a)google.com> Reviewed-by: Jann Horn <jannh(a)google.com> Cc: Andrey Konovalov <andreyknvl(a)google.com> Cc: Andrey Ryabinin <aryabinin(a)virtuozzo.com> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Catalin Marinas <catalin.marinas(a)arm.com> Cc: Christopher Lameter <cl(a)linux.com> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: David Rientjes <rientjes(a)google.com> Cc: Eric Dumazet <edumazet(a)google.com> Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Cc: Hillf Danton <hdanton(a)sina.com> Cc: "H. Peter Anvin" <hpa(a)zytor.com> Cc: Ingo Molnar <mingo(a)redhat.com> Cc: Joern Engel <joern(a)purestorage.com> Cc: Jonathan Corbet <corbet(a)lwn.net> Cc: Joonsoo Kim <iamjoonsoo.kim(a)lge.com> Cc: Kees Cook <keescook(a)chromium.org> Cc: Mark Rutland <mark.rutland(a)arm.com> Cc: Paul E. McKenney <paulmck(a)kernel.org> Cc: Pekka Enberg <penberg(a)kernel.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: SeongJae Park <sjpark(a)amazon.de> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: Will Deacon <will(a)kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds(a)linux-foundation.org> Signed-off-by: Yingjie Shang <1415317271(a)qq.com> Reviewed-by: Bixuan Cui <cuibixuan(a)huawei.com> --- Documentation/dev-tools/index.rst | 1 + Documentation/dev-tools/kfence.rst | 298 +++++++++++++++++++++++++++++ lib/Kconfig.kfence | 2 + 3 files changed, 301 insertions(+) create mode 100644 Documentation/dev-tools/kfence.rst diff --git a/Documentation/dev-tools/index.rst b/Documentation/dev-tools/index.rst index f7809c7b1ba9..1b1cf4f5c9d9 100644 --- a/Documentation/dev-tools/index.rst +++ b/Documentation/dev-tools/index.rst @@ -22,6 +22,7 @@ whole; patches welcome! ubsan kmemleak kcsan + kfence gdb-kernel-debugging kgdb kselftest diff --git a/Documentation/dev-tools/kfence.rst b/Documentation/dev-tools/kfence.rst new file mode 100644 index 000000000000..0e2fb6ef3016 --- /dev/null +++ b/Documentation/dev-tools/kfence.rst @@ -0,0 +1,298 @@ +.. SPDX-License-Identifier: GPL-2.0 +.. Copyright (C) 2020, Google LLC. + +Kernel Electric-Fence (KFENCE) +============================== + +Kernel Electric-Fence (KFENCE) is a low-overhead sampling-based memory safety +error detector. KFENCE detects heap out-of-bounds access, use-after-free, and +invalid-free errors. + +KFENCE is designed to be enabled in production kernels, and has near zero +performance overhead. Compared to KASAN, KFENCE trades performance for +precision. The main motivation behind KFENCE's design, is that with enough +total uptime KFENCE will detect bugs in code paths not typically exercised by +non-production test workloads. One way to quickly achieve a large enough total +uptime is when the tool is deployed across a large fleet of machines. + +Usage +----- + +To enable KFENCE, configure the kernel with:: + + CONFIG_KFENCE=y + +To build a kernel with KFENCE support, but disabled by default (to enable, set +``kfence.sample_interval`` to non-zero value), configure the kernel with:: + + CONFIG_KFENCE=y + CONFIG_KFENCE_SAMPLE_INTERVAL=0 + +KFENCE provides several other configuration options to customize behaviour (see +the respective help text in ``lib/Kconfig.kfence`` for more info). + +Tuning performance +~~~~~~~~~~~~~~~~~~ + +The most important parameter is KFENCE's sample interval, which can be set via +the kernel boot parameter ``kfence.sample_interval`` in milliseconds. The +sample interval determines the frequency with which heap allocations will be +guarded by KFENCE. The default is configurable via the Kconfig option +``CONFIG_KFENCE_SAMPLE_INTERVAL``. Setting ``kfence.sample_interval=0`` +disables KFENCE. + +The KFENCE memory pool is of fixed size, and if the pool is exhausted, no +further KFENCE allocations occur. With ``CONFIG_KFENCE_NUM_OBJECTS`` (default +255), the number of available guarded objects can be controlled. Each object +requires 2 pages, one for the object itself and the other one used as a guard +page; object pages are interleaved with guard pages, and every object page is +therefore surrounded by two guard pages. + +The total memory dedicated to the KFENCE memory pool can be computed as:: + + ( #objects + 1 ) * 2 * PAGE_SIZE + +Using the default config, and assuming a page size of 4 KiB, results in +dedicating 2 MiB to the KFENCE memory pool. + +Note: On architectures that support huge pages, KFENCE will ensure that the +pool is using pages of size ``PAGE_SIZE``. This will result in additional page +tables being allocated. + +Error reports +~~~~~~~~~~~~~ + +A typical out-of-bounds access looks like this:: + + ================================================================== + BUG: KFENCE: out-of-bounds in test_out_of_bounds_read+0xa3/0x22b + + Out-of-bounds access at 0xffffffffb672efff (1B left of kfence-#17): + test_out_of_bounds_read+0xa3/0x22b + kunit_try_run_case+0x51/0x85 + kunit_generic_run_threadfn_adapter+0x16/0x30 + kthread+0x137/0x160 + ret_from_fork+0x22/0x30 + + kfence-#17 [0xffffffffb672f000-0xffffffffb672f01f, size=32, cache=kmalloc-32] allocated by task 507: + test_alloc+0xf3/0x25b + test_out_of_bounds_read+0x98/0x22b + kunit_try_run_case+0x51/0x85 + kunit_generic_run_threadfn_adapter+0x16/0x30 + kthread+0x137/0x160 + ret_from_fork+0x22/0x30 + + CPU: 4 PID: 107 Comm: kunit_try_catch Not tainted 5.8.0-rc6+ #7 + Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1 04/01/2014 + ================================================================== + +The header of the report provides a short summary of the function involved in +the access. It is followed by more detailed information about the access and +its origin. Note that, real kernel addresses are only shown for +``CONFIG_DEBUG_KERNEL=y`` builds. + +Use-after-free accesses are reported as:: + + ================================================================== + BUG: KFENCE: use-after-free in test_use_after_free_read+0xb3/0x143 + + Use-after-free access at 0xffffffffb673dfe0 (in kfence-#24): + test_use_after_free_read+0xb3/0x143 + kunit_try_run_case+0x51/0x85 + kunit_generic_run_threadfn_adapter+0x16/0x30 + kthread+0x137/0x160 + ret_from_fork+0x22/0x30 + + kfence-#24 [0xffffffffb673dfe0-0xffffffffb673dfff, size=32, cache=kmalloc-32] allocated by task 507: + test_alloc+0xf3/0x25b + test_use_after_free_read+0x76/0x143 + kunit_try_run_case+0x51/0x85 + kunit_generic_run_threadfn_adapter+0x16/0x30 + kthread+0x137/0x160 + ret_from_fork+0x22/0x30 + + freed by task 507: + test_use_after_free_read+0xa8/0x143 + kunit_try_run_case+0x51/0x85 + kunit_generic_run_threadfn_adapter+0x16/0x30 + kthread+0x137/0x160 + ret_from_fork+0x22/0x30 + + CPU: 4 PID: 109 Comm: kunit_try_catch Tainted: G W 5.8.0-rc6+ #7 + Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1 04/01/2014 + ================================================================== + +KFENCE also reports on invalid frees, such as double-frees:: + + ================================================================== + BUG: KFENCE: invalid free in test_double_free+0xdc/0x171 + + Invalid free of 0xffffffffb6741000: + test_double_free+0xdc/0x171 + kunit_try_run_case+0x51/0x85 + kunit_generic_run_threadfn_adapter+0x16/0x30 + kthread+0x137/0x160 + ret_from_fork+0x22/0x30 + + kfence-#26 [0xffffffffb6741000-0xffffffffb674101f, size=32, cache=kmalloc-32] allocated by task 507: + test_alloc+0xf3/0x25b + test_double_free+0x76/0x171 + kunit_try_run_case+0x51/0x85 + kunit_generic_run_threadfn_adapter+0x16/0x30 + kthread+0x137/0x160 + ret_from_fork+0x22/0x30 + + freed by task 507: + test_double_free+0xa8/0x171 + kunit_try_run_case+0x51/0x85 + kunit_generic_run_threadfn_adapter+0x16/0x30 + kthread+0x137/0x160 + ret_from_fork+0x22/0x30 + + CPU: 4 PID: 111 Comm: kunit_try_catch Tainted: G W 5.8.0-rc6+ #7 + Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1 04/01/2014 + ================================================================== + +KFENCE also uses pattern-based redzones on the other side of an object's guard +page, to detect out-of-bounds writes on the unprotected side of the object. +These are reported on frees:: + + ================================================================== + BUG: KFENCE: memory corruption in test_kmalloc_aligned_oob_write+0xef/0x184 + + Corrupted memory at 0xffffffffb6797ff9 [ 0xac . . . . . . ] (in kfence-#69): + test_kmalloc_aligned_oob_write+0xef/0x184 + kunit_try_run_case+0x51/0x85 + kunit_generic_run_threadfn_adapter+0x16/0x30 + kthread+0x137/0x160 + ret_from_fork+0x22/0x30 + + kfence-#69 [0xffffffffb6797fb0-0xffffffffb6797ff8, size=73, cache=kmalloc-96] allocated by task 507: + test_alloc+0xf3/0x25b + test_kmalloc_aligned_oob_write+0x57/0x184 + kunit_try_run_case+0x51/0x85 + kunit_generic_run_threadfn_adapter+0x16/0x30 + kthread+0x137/0x160 + ret_from_fork+0x22/0x30 + + CPU: 4 PID: 120 Comm: kunit_try_catch Tainted: G W 5.8.0-rc6+ #7 + Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1 04/01/2014 + ================================================================== + +For such errors, the address where the corruption occurred as well as the +invalidly written bytes (offset from the address) are shown; in this +representation, '.' denote untouched bytes. In the example above ``0xac`` is +the value written to the invalid address at offset 0, and the remaining '.' +denote that no following bytes have been touched. Note that, real values are +only shown for ``CONFIG_DEBUG_KERNEL=y`` builds; to avoid information +disclosure for non-debug builds, '!' is used instead to denote invalidly +written bytes. + +And finally, KFENCE may also report on invalid accesses to any protected page +where it was not possible to determine an associated object, e.g. if adjacent +object pages had not yet been allocated:: + + ================================================================== + BUG: KFENCE: invalid access in test_invalid_access+0x26/0xe0 + + Invalid access at 0xffffffffb670b00a: + test_invalid_access+0x26/0xe0 + kunit_try_run_case+0x51/0x85 + kunit_generic_run_threadfn_adapter+0x16/0x30 + kthread+0x137/0x160 + ret_from_fork+0x22/0x30 + + CPU: 4 PID: 124 Comm: kunit_try_catch Tainted: G W 5.8.0-rc6+ #7 + Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1 04/01/2014 + ================================================================== + +DebugFS interface +~~~~~~~~~~~~~~~~~ + +Some debugging information is exposed via debugfs: + +* The file ``/sys/kernel/debug/kfence/stats`` provides runtime statistics. + +* The file ``/sys/kernel/debug/kfence/objects`` provides a list of objects + allocated via KFENCE, including those already freed but protected. + +Implementation Details +---------------------- + +Guarded allocations are set up based on the sample interval. After expiration +of the sample interval, the next allocation through the main allocator (SLAB or +SLUB) returns a guarded allocation from the KFENCE object pool (allocation +sizes up to PAGE_SIZE are supported). At this point, the timer is reset, and +the next allocation is set up after the expiration of the interval. To "gate" a +KFENCE allocation through the main allocator's fast-path without overhead, +KFENCE relies on static branches via the static keys infrastructure. The static +branch is toggled to redirect the allocation to KFENCE. + +KFENCE objects each reside on a dedicated page, at either the left or right +page boundaries selected at random. The pages to the left and right of the +object page are "guard pages", whose attributes are changed to a protected +state, and cause page faults on any attempted access. Such page faults are then +intercepted by KFENCE, which handles the fault gracefully by reporting an +out-of-bounds access, and marking the page as accessible so that the faulting +code can (wrongly) continue executing (set ``panic_on_warn`` to panic instead). + +To detect out-of-bounds writes to memory within the object's page itself, +KFENCE also uses pattern-based redzones. For each object page, a redzone is set +up for all non-object memory. For typical alignments, the redzone is only +required on the unguarded side of an object. Because KFENCE must honor the +cache's requested alignment, special alignments may result in unprotected gaps +on either side of an object, all of which are redzoned. + +The following figure illustrates the page layout:: + + ---+-----------+-----------+-----------+-----------+-----------+--- + | xxxxxxxxx | O : | xxxxxxxxx | : O | xxxxxxxxx | + | xxxxxxxxx | B : | xxxxxxxxx | : B | xxxxxxxxx | + | x GUARD x | J : RED- | x GUARD x | RED- : J | x GUARD x | + | xxxxxxxxx | E : ZONE | xxxxxxxxx | ZONE : E | xxxxxxxxx | + | xxxxxxxxx | C : | xxxxxxxxx | : C | xxxxxxxxx | + | xxxxxxxxx | T : | xxxxxxxxx | : T | xxxxxxxxx | + ---+-----------+-----------+-----------+-----------+-----------+--- + +Upon deallocation of a KFENCE object, the object's page is again protected and +the object is marked as freed. Any further access to the object causes a fault +and KFENCE reports a use-after-free access. Freed objects are inserted at the +tail of KFENCE's freelist, so that the least recently freed objects are reused +first, and the chances of detecting use-after-frees of recently freed objects +is increased. + +Interface +--------- + +The following describes the functions which are used by allocators as well as +page handling code to set up and deal with KFENCE allocations. + +.. kernel-doc:: include/linux/kfence.h + :functions: is_kfence_address + kfence_shutdown_cache + kfence_alloc kfence_free __kfence_free + kfence_ksize kfence_object_start + kfence_handle_page_fault + +Related Tools +------------- + +In userspace, a similar approach is taken by `GWP-ASan +<http://llvm.org/docs/GwpAsan.html>`_. GWP-ASan also relies on guard pages and +a sampling strategy to detect memory unsafety bugs at scale. KFENCE's design is +directly influenced by GWP-ASan, and can be seen as its kernel sibling. Another +similar but non-sampling approach, that also inspired the name "KFENCE", can be +found in the userspace `Electric Fence Malloc Debugger +<https://linux.die.net/man/3/efence>`_. + +In the kernel, several tools exist to debug memory access errors, and in +particular KASAN can detect all bug classes that KFENCE can detect. While KASAN +is more precise, relying on compiler instrumentation, this comes at a +performance cost. + +It is worth highlighting that KASAN and KFENCE are complementary, with +different target environments. For instance, KASAN is the better debugging-aid, +where test cases or reproducers exists: due to the lower chance to detect the +error, it would require more effort using KFENCE to debug. Deployments at scale +that cannot afford to enable KASAN, however, would benefit from using KFENCE to +discover bugs due to code paths not exercised by test cases or fuzzers. diff --git a/lib/Kconfig.kfence b/lib/Kconfig.kfence index edfecb5d6165..605125ac2ae0 100644 --- a/lib/Kconfig.kfence +++ b/lib/Kconfig.kfence @@ -13,6 +13,8 @@ menuconfig KFENCE to have negligible cost to permit enabling it in production environments. + See <file:Documentation/dev-tools/kfence.rst> for more details. + Note that, KFENCE is not a substitute for explicit testing with tools such as KASAN. KFENCE can detect a subset of bugs that KASAN can detect, albeit at very different performance profiles. If you can -- 2.25.1

1 0

[PATCH 7/9] kfence, kasan: make KFENCE compatible with KASAN
by 1415317271＠qq.com 18 Aug '21

18 Aug '21

From: Alexander Potapenko <glider(a)google.com> Make KFENCE compatible with KASAN. Currently this helps test KFENCE itself, where KASAN can catch potential corruptions to KFENCE state, or other corruptions that may be a result of freepointer corruptions in the main allocators. [akpm(a)linux-foundation.org: merge fixup] [andreyknvl(a)google.com: untag addresses for KFENCE] Link: https://lkml.kernel.org/r/9dc196006921b191d25d10f6e611316db7da2efc.16119461… Link: https://lkml.kernel.org/r/20201103175841.3495947-7-elver@google.com Signed-off-by: Marco Elver <elver(a)google.com> Signed-off-by: Alexander Potapenko <glider(a)google.com> Signed-off-by: Andrey Konovalov <andreyknvl(a)google.com> Reviewed-by: Dmitry Vyukov <dvyukov(a)google.com> Reviewed-by: Jann Horn <jannh(a)google.com> Co-developed-by: Marco Elver <elver(a)google.com> Cc: Andrey Konovalov <andreyknvl(a)google.com> Cc: Andrey Ryabinin <aryabinin(a)virtuozzo.com> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Catalin Marinas <catalin.marinas(a)arm.com> Cc: Christopher Lameter <cl(a)linux.com> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: David Rientjes <rientjes(a)google.com> Cc: Eric Dumazet <edumazet(a)google.com> Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Cc: Hillf Danton <hdanton(a)sina.com> Cc: "H. Peter Anvin" <hpa(a)zytor.com> Cc: Ingo Molnar <mingo(a)redhat.com> Cc: Joern Engel <joern(a)purestorage.com> Cc: Jonathan Corbet <corbet(a)lwn.net> Cc: Joonsoo Kim <iamjoonsoo.kim(a)lge.com> Cc: Kees Cook <keescook(a)chromium.org> Cc: Mark Rutland <mark.rutland(a)arm.com> Cc: Paul E. McKenney <paulmck(a)kernel.org> Cc: Pekka Enberg <penberg(a)kernel.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: SeongJae Park <sjpark(a)amazon.de> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: Will Deacon <will(a)kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds(a)linux-foundation.org> Signed-off-by: Yingjie Shang <1415317271(a)qq.com> Reviewed-by: Bixuan Cui <cuibixuan(a)huawei.com> --- lib/Kconfig.kfence | 2 +- mm/kasan/common.c | 6 ++++++ mm/kasan/generic.c | 3 ++- 3 files changed, 9 insertions(+), 2 deletions(-) diff --git a/lib/Kconfig.kfence b/lib/Kconfig.kfence index b88ac9d6b2e6..edfecb5d6165 100644 --- a/lib/Kconfig.kfence +++ b/lib/Kconfig.kfence @@ -5,7 +5,7 @@ config HAVE_ARCH_KFENCE menuconfig KFENCE bool "KFENCE: low-overhead sampling-based memory safety error detector" - depends on HAVE_ARCH_KFENCE && !KASAN && (SLAB || SLUB) + depends on HAVE_ARCH_KFENCE && (SLAB || SLUB) select STACKTRACE help KFENCE is a low-overhead sampling-based detector of heap out-of-bounds diff --git a/mm/kasan/common.c b/mm/kasan/common.c index 950fd372a07e..d9a25af29354 100644 --- a/mm/kasan/common.c +++ b/mm/kasan/common.c @@ -396,6 +396,9 @@ static bool __kasan_slab_free(struct kmem_cache *cache, void *object, tagged_object = object; object = reset_tag(object); + if (is_kfence_address(object)) + return false; + if (unlikely(nearest_obj(cache, virt_to_head_page(object), object) != object)) { kasan_report_invalid_free(tagged_object, ip); @@ -444,6 +447,9 @@ static void *__kasan_kmalloc(struct kmem_cache *cache, const void *object, if (unlikely(object == NULL)) return NULL; + if (is_kfence_address(kasan_reset_tag(object))) + return (void *)object; + redzone_start = round_up((unsigned long)(object + size), KASAN_SHADOW_SCALE_SIZE); redzone_end = round_up((unsigned long)object + cache->object_size, diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c index 2efc48444e77..c4c56ec8a472 100644 --- a/mm/kasan/generic.c +++ b/mm/kasan/generic.c @@ -21,6 +21,7 @@ #include <linux/init.h> #include <linux/kasan.h> #include <linux/kernel.h> +#include <linux/kfence.h> #include <linux/kmemleak.h> #include <linux/linkage.h> #include <linux/memblock.h> @@ -332,7 +333,7 @@ void kasan_record_aux_stack(void *addr) struct kasan_alloc_meta *alloc_info; void *object; - if (!(page && PageSlab(page))) + if (is_kfence_address(addr) || !(page && PageSlab(page))) return; cache = page->slab_cache; -- 2.25.1

1 0

[PATCH 6/9] mm, kfence: insert KFENCE hooks for SLUB
by 1415317271＠qq.com 18 Aug '21

18 Aug '21

From: Alexander Potapenko <glider(a)google.com> Inserts KFENCE hooks into the SLUB allocator. To pass the originally requested size to KFENCE, add an argument 'orig_size' to slab_alloc*(). The additional argument is required to preserve the requested original size for kmalloc() allocations, which uses size classes (e.g. an allocation of 272 bytes will return an object of size 512). Therefore, kmem_cache::size does not represent the kmalloc-caller's requested size, and we must introduce the argument 'orig_size' to propagate the originally requested size to KFENCE. Without the originally requested size, we would not be able to detect out-of-bounds accesses for objects placed at the end of a KFENCE object page if that object is not equal to the kmalloc-size class it was bucketed into. When KFENCE is disabled, there is no additional overhead, since slab_alloc*() functions are __always_inline. Link: https://lkml.kernel.org/r/20201103175841.3495947-6-elver@google.com Signed-off-by: Marco Elver <elver(a)google.com> Signed-off-by: Alexander Potapenko <glider(a)google.com> Reviewed-by: Dmitry Vyukov <dvyukov(a)google.com> Reviewed-by: Jann Horn <jannh(a)google.com> Co-developed-by: Marco Elver <elver(a)google.com> Cc: Andrey Konovalov <andreyknvl(a)google.com> Cc: Andrey Ryabinin <aryabinin(a)virtuozzo.com> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Catalin Marinas <catalin.marinas(a)arm.com> Cc: Christopher Lameter <cl(a)linux.com> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: David Rientjes <rientjes(a)google.com> Cc: Eric Dumazet <edumazet(a)google.com> Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Cc: Hillf Danton <hdanton(a)sina.com> Cc: "H. Peter Anvin" <hpa(a)zytor.com> Cc: Ingo Molnar <mingo(a)redhat.com> Cc: Joern Engel <joern(a)purestorage.com> Cc: Jonathan Corbet <corbet(a)lwn.net> Cc: Joonsoo Kim <iamjoonsoo.kim(a)lge.com> Cc: Kees Cook <keescook(a)chromium.org> Cc: Mark Rutland <mark.rutland(a)arm.com> Cc: Paul E. McKenney <paulmck(a)kernel.org> Cc: Pekka Enberg <penberg(a)kernel.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: SeongJae Park <sjpark(a)amazon.de> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: Will Deacon <will(a)kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds(a)linux-foundation.org> Signed-off-by: Yingjie Shang <1415317271(a)qq.com> Reviewed-by: Bixuan Cui <cuibixuan(a)huawei.com> --- include/linux/slub_def.h | 3 ++ mm/kfence/core.c | 2 ++ mm/slub.c | 61 ++++++++++++++++++++++++++++++---------- 3 files changed, 51 insertions(+), 15 deletions(-) diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h index 1be0ed5befa1..dcde82a4434c 100644 --- a/include/linux/slub_def.h +++ b/include/linux/slub_def.h @@ -7,6 +7,7 @@ * * (C) 2007 SGI, Christoph Lameter */ +#include <linux/kfence.h> #include <linux/kobject.h> #include <linux/reciprocal_div.h> @@ -185,6 +186,8 @@ static inline unsigned int __obj_to_index(const struct kmem_cache *cache, static inline unsigned int obj_to_index(const struct kmem_cache *cache, const struct page *page, void *obj) { + if (is_kfence_address(obj)) + return 0; return __obj_to_index(cache, page_address(page), obj); } diff --git a/mm/kfence/core.c b/mm/kfence/core.c index 05c18aa11851..7692af715fdb 100644 --- a/mm/kfence/core.c +++ b/mm/kfence/core.c @@ -317,6 +317,8 @@ static void *kfence_guarded_alloc(struct kmem_cache *cache, size_t size, gfp_t g /* Set required struct page fields. */ page = virt_to_page(meta->addr); page->slab_cache = cache; + if (IS_ENABLED(CONFIG_SLUB)) + page->objects = 1; if (IS_ENABLED(CONFIG_SLAB)) page->s_mem = addr; diff --git a/mm/slub.c b/mm/slub.c index f06f002bb098..678c29105d7f 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -28,6 +28,7 @@ #include <linux/ctype.h> #include <linux/debugobjects.h> #include <linux/kallsyms.h> +#include <linux/kfence.h> #include <linux/memory.h> #include <linux/math64.h> #include <linux/fault-inject.h> @@ -1560,6 +1561,11 @@ static inline bool slab_free_freelist_hook(struct kmem_cache *s, void *old_tail = *tail ? *tail : *head; int rsize; + if (is_kfence_address(next)) { + slab_free_hook(s, next); + return true; + } + /* Head and tail of the reconstructed freelist */ *head = NULL; *tail = NULL; @@ -2801,7 +2807,7 @@ static __always_inline void maybe_wipe_obj_freeptr(struct kmem_cache *s, * Otherwise we can simply pick the next object from the lockless free list. */ static __always_inline void *slab_alloc_node(struct kmem_cache *s, - gfp_t gfpflags, int node, unsigned long addr) + gfp_t gfpflags, int node, unsigned long addr, size_t orig_size) { void *object; struct kmem_cache_cpu *c; @@ -2812,6 +2818,11 @@ static __always_inline void *slab_alloc_node(struct kmem_cache *s, s = slab_pre_alloc_hook(s, &objcg, 1, gfpflags); if (!s) return NULL; + + object = kfence_alloc(s, orig_size, gfpflags); + if (unlikely(object)) + goto out; + redo: /* * Must read kmem_cache cpu data via this cpu ptr. Preemption is @@ -2883,21 +2894,21 @@ static __always_inline void *slab_alloc_node(struct kmem_cache *s, if (unlikely(slab_want_init_on_alloc(gfpflags, s)) && object) memset(object, 0, s->object_size); - +out: slab_post_alloc_hook(s, objcg, gfpflags, 1, &object); return object; } static __always_inline void *slab_alloc(struct kmem_cache *s, - gfp_t gfpflags, unsigned long addr) + gfp_t gfpflags, unsigned long addr, size_t orig_size) { - return slab_alloc_node(s, gfpflags, NUMA_NO_NODE, addr); + return slab_alloc_node(s, gfpflags, NUMA_NO_NODE, addr, orig_size); } void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags) { - void *ret = slab_alloc(s, gfpflags, _RET_IP_); + void *ret = slab_alloc(s, gfpflags, _RET_IP_, s->object_size); trace_kmem_cache_alloc(_RET_IP_, ret, s->object_size, s->size, gfpflags); @@ -2909,7 +2920,7 @@ EXPORT_SYMBOL(kmem_cache_alloc); #ifdef CONFIG_TRACING void *kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size) { - void *ret = slab_alloc(s, gfpflags, _RET_IP_); + void *ret = slab_alloc(s, gfpflags, _RET_IP_, size); trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags); ret = kasan_kmalloc(s, ret, size, gfpflags); return ret; @@ -2920,7 +2931,7 @@ EXPORT_SYMBOL(kmem_cache_alloc_trace); #ifdef CONFIG_NUMA void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node) { - void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_); + void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_, s->object_size); trace_kmem_cache_alloc_node(_RET_IP_, ret, s->object_size, s->size, gfpflags, node); @@ -2934,7 +2945,7 @@ void *kmem_cache_alloc_node_trace(struct kmem_cache *s, gfp_t gfpflags, int node, size_t size) { - void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_); + void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_, size); trace_kmalloc_node(_RET_IP_, ret, size, s->size, gfpflags, node); @@ -2968,6 +2979,9 @@ static void __slab_free(struct kmem_cache *s, struct page *page, stat(s, FREE_SLOWPATH); + if (kfence_free(head)) + return; + if (kmem_cache_debug(s) && !free_debug_processing(s, page, head, tail, cnt, addr)) return; @@ -3212,6 +3226,13 @@ int build_detached_freelist(struct kmem_cache *s, size_t size, df->s = cache_from_obj(s, object); /* Support for memcg */ } + if (is_kfence_address(object)) { + slab_free_hook(df->s, object); + __kfence_free(object); + p[size] = NULL; /* mark object processed */ + return size; + } + /* Start new detached freelist */ df->page = page; set_freepointer(df->s, object, NULL); @@ -3287,8 +3308,14 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size, c = this_cpu_ptr(s->cpu_slab); for (i = 0; i < size; i++) { - void *object = c->freelist; + void *object = kfence_alloc(s, s->object_size, flags); + if (unlikely(object)) { + p[i] = object; + continue; + } + + object = c->freelist; if (unlikely(!object)) { /* * We may have removed an object from c->freelist using @@ -3953,7 +3980,7 @@ void *__kmalloc(size_t size, gfp_t flags) if (unlikely(ZERO_OR_NULL_PTR(s))) return s; - ret = slab_alloc(s, flags, _RET_IP_); + ret = slab_alloc(s, flags, _RET_IP_, size); trace_kmalloc(_RET_IP_, ret, size, s->size, flags); @@ -4001,7 +4028,7 @@ void *__kmalloc_node(size_t size, gfp_t flags, int node) if (unlikely(ZERO_OR_NULL_PTR(s))) return s; - ret = slab_alloc_node(s, flags, node, _RET_IP_); + ret = slab_alloc_node(s, flags, node, _RET_IP_, size); trace_kmalloc_node(_RET_IP_, ret, size, s->size, flags, node); @@ -4027,6 +4054,7 @@ void __check_heap_object(const void *ptr, unsigned long n, struct page *page, struct kmem_cache *s; unsigned int offset; size_t object_size; + bool is_kfence = is_kfence_address(ptr); ptr = kasan_reset_tag(ptr); @@ -4039,10 +4067,13 @@ void __check_heap_object(const void *ptr, unsigned long n, struct page *page, to_user, 0, n); /* Find offset within object. */ - offset = (ptr - page_address(page)) % s->size; + if (is_kfence) + offset = ptr - kfence_object_start(ptr); + else + offset = (ptr - page_address(page)) % s->size; /* Adjust for redzone and reject if within the redzone. */ - if (kmem_cache_debug_flags(s, SLAB_RED_ZONE)) { + if (!is_kfence && kmem_cache_debug_flags(s, SLAB_RED_ZONE)) { if (offset < s->red_left_pad) usercopy_abort("SLUB object in left red zone", s->name, to_user, offset, n); @@ -4459,7 +4490,7 @@ void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, unsigned long caller) if (unlikely(ZERO_OR_NULL_PTR(s))) return s; - ret = slab_alloc(s, gfpflags, caller); + ret = slab_alloc(s, gfpflags, caller, size); /* Honor the call site pointer we received. */ trace_kmalloc(caller, ret, size, s->size, gfpflags); @@ -4490,7 +4521,7 @@ void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags, if (unlikely(ZERO_OR_NULL_PTR(s))) return s; - ret = slab_alloc_node(s, gfpflags, node, caller); + ret = slab_alloc_node(s, gfpflags, node, caller, size); /* Honor the call site pointer we received. */ trace_kmalloc_node(caller, ret, size, s->size, gfpflags, node); -- 2.25.1

1 0

[PATCH 5/9] mm, kfence: insert KFENCE hooks for SLAB
by 1415317271＠qq.com 18 Aug '21

18 Aug '21

From: Alexander Potapenko <glider(a)google.com> Inserts KFENCE hooks into the SLAB allocator. To pass the originally requested size to KFENCE, add an argument 'orig_size' to slab_alloc*(). The additional argument is required to preserve the requested original size for kmalloc() allocations, which uses size classes (e.g. an allocation of 272 bytes will return an object of size 512). Therefore, kmem_cache::size does not represent the kmalloc-caller's requested size, and we must introduce the argument 'orig_size' to propagate the originally requested size to KFENCE. Without the originally requested size, we would not be able to detect out-of-bounds accesses for objects placed at the end of a KFENCE object page if that object is not equal to the kmalloc-size class it was bucketed into. When KFENCE is disabled, there is no additional overhead, since slab_alloc*() functions are __always_inline. Link: https://lkml.kernel.org/r/20201103175841.3495947-5-elver@google.com Signed-off-by: Marco Elver <elver(a)google.com> Signed-off-by: Alexander Potapenko <glider(a)google.com> Reviewed-by: Dmitry Vyukov <dvyukov(a)google.com> Co-developed-by: Marco Elver <elver(a)google.com> Cc: Christoph Lameter <cl(a)linux.com> Cc: Pekka Enberg <penberg(a)kernel.org> Cc: David Rientjes <rientjes(a)google.com> Cc: Joonsoo Kim <iamjoonsoo.kim(a)lge.com> Cc: Andrey Konovalov <andreyknvl(a)google.com> Cc: Andrey Ryabinin <aryabinin(a)virtuozzo.com> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Catalin Marinas <catalin.marinas(a)arm.com> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: Eric Dumazet <edumazet(a)google.com> Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Cc: Hillf Danton <hdanton(a)sina.com> Cc: "H. Peter Anvin" <hpa(a)zytor.com> Cc: Ingo Molnar <mingo(a)redhat.com> Cc: Jann Horn <jannh(a)google.com> Cc: Joern Engel <joern(a)purestorage.com> Cc: Jonathan Corbet <corbet(a)lwn.net> Cc: Kees Cook <keescook(a)chromium.org> Cc: Mark Rutland <mark.rutland(a)arm.com> Cc: Paul E. McKenney <paulmck(a)kernel.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: SeongJae Park <sjpark(a)amazon.de> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: Will Deacon <will(a)kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds(a)linux-foundation.org> Signed-off-by: Yingjie Shang <1415317271(a)qq.com> Reviewed-by: Bixuan Cui <cuibixuan(a)huawei.com> --- include/linux/slab_def.h | 3 +++ mm/kfence/core.c | 2 ++ mm/slab.c | 38 +++++++++++++++++++++++++++++--------- mm/slab_common.c | 5 ++++- 4 files changed, 38 insertions(+), 10 deletions(-) diff --git a/include/linux/slab_def.h b/include/linux/slab_def.h index 9eb430c163c2..3aa5e1e73ab6 100644 --- a/include/linux/slab_def.h +++ b/include/linux/slab_def.h @@ -2,6 +2,7 @@ #ifndef _LINUX_SLAB_DEF_H #define _LINUX_SLAB_DEF_H +#include <linux/kfence.h> #include <linux/reciprocal_div.h> /* @@ -114,6 +115,8 @@ static inline unsigned int obj_to_index(const struct kmem_cache *cache, static inline int objs_per_slab_page(const struct kmem_cache *cache, const struct page *page) { + if (is_kfence_address(page_address(page))) + return 1; return cache->num; } diff --git a/mm/kfence/core.c b/mm/kfence/core.c index 61c76670a7a9..05c18aa11851 100644 --- a/mm/kfence/core.c +++ b/mm/kfence/core.c @@ -317,6 +317,8 @@ static void *kfence_guarded_alloc(struct kmem_cache *cache, size_t size, gfp_t g /* Set required struct page fields. */ page = virt_to_page(meta->addr); page->slab_cache = cache; + if (IS_ENABLED(CONFIG_SLAB)) + page->s_mem = addr; raw_spin_unlock_irqrestore(&meta->lock, flags); diff --git a/mm/slab.c b/mm/slab.c index b2cc2cf7d8a3..4b526a0434f5 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -100,6 +100,7 @@ #include <linux/seq_file.h> #include <linux/notifier.h> #include <linux/kallsyms.h> +#include <linux/kfence.h> #include <linux/cpu.h> #include <linux/sysctl.h> #include <linux/module.h> @@ -3207,7 +3208,7 @@ static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, } static __always_inline void * -slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid, +slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid, size_t orig_size, unsigned long caller) { unsigned long save_flags; @@ -3220,6 +3221,10 @@ slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid, if (unlikely(!cachep)) return NULL; + ptr = kfence_alloc(cachep, orig_size, flags); + if (unlikely(ptr)) + goto out_hooks; + cache_alloc_debugcheck_before(cachep, flags); local_irq_save(save_flags); @@ -3252,6 +3257,7 @@ slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid, if (unlikely(slab_want_init_on_alloc(flags, cachep)) && ptr) memset(ptr, 0, cachep->object_size); +out_hooks: slab_post_alloc_hook(cachep, objcg, flags, 1, &ptr); return ptr; } @@ -3289,7 +3295,7 @@ __do_cache_alloc(struct kmem_cache *cachep, gfp_t flags) #endif /* CONFIG_NUMA */ static __always_inline void * -slab_alloc(struct kmem_cache *cachep, gfp_t flags, unsigned long caller) +slab_alloc(struct kmem_cache *cachep, gfp_t flags, size_t orig_size, unsigned long caller) { unsigned long save_flags; void *objp; @@ -3300,6 +3306,10 @@ slab_alloc(struct kmem_cache *cachep, gfp_t flags, unsigned long caller) if (unlikely(!cachep)) return NULL; + objp = kfence_alloc(cachep, orig_size, flags); + if (unlikely(objp)) + goto out; + cache_alloc_debugcheck_before(cachep, flags); local_irq_save(save_flags); objp = __do_cache_alloc(cachep, flags); @@ -3310,6 +3320,7 @@ slab_alloc(struct kmem_cache *cachep, gfp_t flags, unsigned long caller) if (unlikely(slab_want_init_on_alloc(flags, cachep)) && objp) memset(objp, 0, cachep->object_size); +out: slab_post_alloc_hook(cachep, objcg, flags, 1, &objp); return objp; } @@ -3415,6 +3426,12 @@ static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac) static __always_inline void __cache_free(struct kmem_cache *cachep, void *objp, unsigned long caller) { + if (is_kfence_address(objp)) { + kmemleak_free_recursive(objp, cachep->flags); + __kfence_free(objp); + return; + } + /* Put the object into the quarantine, don't touch it for now. */ if (kasan_slab_free(cachep, objp, _RET_IP_)) return; @@ -3480,7 +3497,7 @@ void ___cache_free(struct kmem_cache *cachep, void *objp, */ void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags) { - void *ret = slab_alloc(cachep, flags, _RET_IP_); + void *ret = slab_alloc(cachep, flags, cachep->object_size, _RET_IP_); trace_kmem_cache_alloc(_RET_IP_, ret, cachep->object_size, cachep->size, flags); @@ -3513,7 +3530,7 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size, local_irq_disable(); for (i = 0; i < size; i++) { - void *objp = __do_cache_alloc(s, flags); + void *objp = kfence_alloc(s, s->object_size, flags) ?: __do_cache_alloc(s, flags); if (unlikely(!objp)) goto error; @@ -3546,7 +3563,7 @@ kmem_cache_alloc_trace(struct kmem_cache *cachep, gfp_t flags, size_t size) { void *ret; - ret = slab_alloc(cachep, flags, _RET_IP_); + ret = slab_alloc(cachep, flags, size, _RET_IP_); ret = kasan_kmalloc(cachep, ret, size, flags); trace_kmalloc(_RET_IP_, ret, @@ -3572,7 +3589,7 @@ EXPORT_SYMBOL(kmem_cache_alloc_trace); */ void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid) { - void *ret = slab_alloc_node(cachep, flags, nodeid, _RET_IP_); + void *ret = slab_alloc_node(cachep, flags, nodeid, cachep->object_size, _RET_IP_); trace_kmem_cache_alloc_node(_RET_IP_, ret, cachep->object_size, cachep->size, @@ -3590,7 +3607,7 @@ void *kmem_cache_alloc_node_trace(struct kmem_cache *cachep, { void *ret; - ret = slab_alloc_node(cachep, flags, nodeid, _RET_IP_); + ret = slab_alloc_node(cachep, flags, nodeid, size, _RET_IP_); ret = kasan_kmalloc(cachep, ret, size, flags); trace_kmalloc_node(_RET_IP_, ret, @@ -3651,7 +3668,7 @@ static __always_inline void *__do_kmalloc(size_t size, gfp_t flags, cachep = kmalloc_slab(size, flags); if (unlikely(ZERO_OR_NULL_PTR(cachep))) return cachep; - ret = slab_alloc(cachep, flags, caller); + ret = slab_alloc(cachep, flags, size, caller); ret = kasan_kmalloc(cachep, ret, size, flags); trace_kmalloc(caller, ret, @@ -4150,7 +4167,10 @@ void __check_heap_object(const void *ptr, unsigned long n, struct page *page, BUG_ON(objnr >= cachep->num); /* Find offset within object. */ - offset = ptr - index_to_obj(cachep, page, objnr) - obj_offset(cachep); + if (is_kfence_address(ptr)) + offset = ptr - kfence_object_start(ptr); + else + offset = ptr - index_to_obj(cachep, page, objnr) - obj_offset(cachep); /* Allow address range falling entirely within usercopy region. */ if (offset >= cachep->useroffset && diff --git a/mm/slab_common.c b/mm/slab_common.c index 79ae785f2c9f..89022933dfa6 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -12,6 +12,7 @@ #include <linux/memory.h> #include <linux/cache.h> #include <linux/compiler.h> +#include <linux/kfence.h> #include <linux/module.h> #include <linux/cpu.h> #include <linux/uaccess.h> @@ -428,6 +429,7 @@ static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work) rcu_barrier(); list_for_each_entry_safe(s, s2, &to_destroy, list) { + kfence_shutdown_cache(s); #ifdef SLAB_SUPPORTS_SYSFS sysfs_slab_release(s); #else @@ -453,6 +455,7 @@ static int shutdown_cache(struct kmem_cache *s) list_add_tail(&s->list, &slab_caches_to_rcu_destroy); schedule_work(&slab_caches_to_rcu_destroy_work); } else { + kfence_shutdown_cache(s); #ifdef SLAB_SUPPORTS_SYSFS sysfs_slab_unlink(s); sysfs_slab_release(s); @@ -1156,7 +1159,7 @@ size_t ksize(const void *objp) if (unlikely(ZERO_OR_NULL_PTR(objp)) || !__kasan_check_read(objp, 1)) return 0; - size = __ksize(objp); + size = kfence_ksize(objp) ?: __ksize(objp); /* * We assume that ksize callers could use whole allocated area, * so we need to unpoison this area. -- 2.25.1

1 0

[PATCH 4/9] kfence: use pt_regs to generate stack trace on faults
by 1415317271＠qq.com 18 Aug '21

18 Aug '21

From: Marco Elver <elver(a)google.com> Instead of removing the fault handling portion of the stack trace based on the fault handler's name, just use struct pt_regs directly. Change kfence_handle_page_fault() to take a struct pt_regs, and plumb it through to kfence_report_error() for out-of-bounds, use-after-free, or invalid access errors, where pt_regs is used to generate the stack trace. If the kernel is a DEBUG_KERNEL, also show registers for more information. Link: https://lkml.kernel.org/r/20201105092133.2075331-1-elver@google.com Signed-off-by: Marco Elver <elver(a)google.com> Suggested-by: Mark Rutland <mark.rutland(a)arm.com> Acked-by: Mark Rutland <mark.rutland(a)arm.com> Cc: Alexander Potapenko <glider(a)google.com> Cc: Dmitry Vyukov <dvyukov(a)google.com> Cc: Jann Horn <jannh(a)google.com> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds(a)linux-foundation.org> Signed-off-by: Yingjie Shang <1415317271(a)qq.com> Reviewed-by: Bixuan Cui <cuibixuan(a)huawei.com> --- arch/arm64/include/asm/kfence.h | 2 -- arch/arm64/mm/fault.c | 2 +- arch/x86/include/asm/kfence.h | 6 ---- arch/x86/mm/fault.c | 2 +- include/linux/kfence.h | 5 +-- mm/kfence/core.c | 10 +++--- mm/kfence/kfence.h | 4 +-- mm/kfence/report.c | 63 +++++++++++++++++++-------------- 8 files changed, 48 insertions(+), 46 deletions(-) diff --git a/arch/arm64/include/asm/kfence.h b/arch/arm64/include/asm/kfence.h index 42a06f83850a..d061176d57ea 100644 --- a/arch/arm64/include/asm/kfence.h +++ b/arch/arm64/include/asm/kfence.h @@ -10,8 +10,6 @@ #include <asm/cacheflush.h> -#define KFENCE_SKIP_ARCH_FAULT_HANDLER "el1_sync" - static inline bool arch_kfence_init_pool(void) { return true; } static inline bool kfence_protect_page(unsigned long addr, bool protect) diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index d1a8b523d28e..a5fe9f7b423b 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -323,7 +323,7 @@ static void __do_kernel_fault(unsigned long addr, unsigned int esr, } else if (addr < PAGE_SIZE) { msg = "NULL pointer dereference"; } else { - if (kfence_handle_page_fault(addr)) + if (kfence_handle_page_fault(addr, regs)) return; msg = "paging request"; diff --git a/arch/x86/include/asm/kfence.h b/arch/x86/include/asm/kfence.h index a0659dbd93ea..97bbb4a9083a 100644 --- a/arch/x86/include/asm/kfence.h +++ b/arch/x86/include/asm/kfence.h @@ -16,12 +16,6 @@ #include <asm/set_memory.h> #include <asm/tlbflush.h> -/* - * The page fault handler entry function, up to which the stack trace is - * truncated in reports. - */ -#define KFENCE_SKIP_ARCH_FAULT_HANDLER "asm_exc_page_fault" - /* Force 4K pages for __kfence_pool. */ static inline bool arch_kfence_init_pool(void) { diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 35901aa6ad1c..f5f359ccaeae 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -734,7 +734,7 @@ no_context(struct pt_regs *regs, unsigned long error_code, efi_recover_from_page_fault(address); /* Only not-present faults should be handled by KFENCE. */ - if (!(error_code & X86_PF_PROT) && kfence_handle_page_fault(address)) + if (!(error_code & X86_PF_PROT) && kfence_handle_page_fault(address, regs)) return; oops: /* diff --git a/include/linux/kfence.h b/include/linux/kfence.h index 81f3911cb298..5a56bcf5606c 100644 --- a/include/linux/kfence.h +++ b/include/linux/kfence.h @@ -186,6 +186,7 @@ static __always_inline __must_check bool kfence_free(void *addr) /** * kfence_handle_page_fault() - perform page fault handling for KFENCE pages * @addr: faulting address + * @regs: current struct pt_regs (can be NULL, but shows full stack trace) * * Return: * * false - address outside KFENCE pool, @@ -196,7 +197,7 @@ static __always_inline __must_check bool kfence_free(void *addr) * cases KFENCE prints an error message and marks the offending page as * present, so that the kernel can proceed. */ -bool __must_check kfence_handle_page_fault(unsigned long addr); +bool __must_check kfence_handle_page_fault(unsigned long addr, struct pt_regs *regs); #else /* CONFIG_KFENCE */ @@ -209,7 +210,7 @@ static inline size_t kfence_ksize(const void *addr) { return 0; } static inline void *kfence_object_start(const void *addr) { return NULL; } static inline void __kfence_free(void *addr) { } static inline bool __must_check kfence_free(void *addr) { return false; } -static inline bool __must_check kfence_handle_page_fault(unsigned long addr) { return false; } +static inline bool __must_check kfence_handle_page_fault(unsigned long addr, struct pt_regs *regs) { return false; } #endif diff --git a/mm/kfence/core.c b/mm/kfence/core.c index d6a32c13336b..61c76670a7a9 100644 --- a/mm/kfence/core.c +++ b/mm/kfence/core.c @@ -216,7 +216,7 @@ static inline bool check_canary_byte(u8 *addr) return true; atomic_long_inc(&counters[KFENCE_COUNTER_BUGS]); - kfence_report_error((unsigned long)addr, addr_to_metadata((unsigned long)addr), + kfence_report_error((unsigned long)addr, NULL, addr_to_metadata((unsigned long)addr), KFENCE_ERROR_CORRUPTION); return false; } @@ -351,7 +351,7 @@ static void kfence_guarded_free(void *addr, struct kfence_metadata *meta, bool z if (meta->state != KFENCE_OBJECT_ALLOCATED || meta->addr != (unsigned long)addr) { /* Invalid or double-free, bail out. */ atomic_long_inc(&counters[KFENCE_COUNTER_BUGS]); - kfence_report_error((unsigned long)addr, meta, KFENCE_ERROR_INVALID_FREE); + kfence_report_error((unsigned long)addr, NULL, meta, KFENCE_ERROR_INVALID_FREE); raw_spin_unlock_irqrestore(&meta->lock, flags); return; } @@ -766,7 +766,7 @@ void __kfence_free(void *addr) kfence_guarded_free(addr, meta, false); } -bool kfence_handle_page_fault(unsigned long addr) +bool kfence_handle_page_fault(unsigned long addr, struct pt_regs *regs) { const int page_index = (addr - (unsigned long)__kfence_pool) / PAGE_SIZE; struct kfence_metadata *to_report = NULL; @@ -829,11 +829,11 @@ bool kfence_handle_page_fault(unsigned long addr) out: if (to_report) { - kfence_report_error(addr, to_report, error_type); + kfence_report_error(addr, regs, to_report, error_type); raw_spin_unlock_irqrestore(&to_report->lock, flags); } else { /* This may be a UAF or OOB access, but we can't be sure. */ - kfence_report_error(addr, NULL, KFENCE_ERROR_INVALID); + kfence_report_error(addr, regs, NULL, KFENCE_ERROR_INVALID); } return kfence_unprotect(addr); /* Unprotect and let access proceed. */ diff --git a/mm/kfence/kfence.h b/mm/kfence/kfence.h index 1014060f9707..0d83e628a97d 100644 --- a/mm/kfence/kfence.h +++ b/mm/kfence/kfence.h @@ -105,8 +105,8 @@ enum kfence_error_type { KFENCE_ERROR_INVALID_FREE, /* Invalid free. */ }; -void kfence_report_error(unsigned long address, const struct kfence_metadata *meta, - enum kfence_error_type type); +void kfence_report_error(unsigned long address, struct pt_regs *regs, + const struct kfence_metadata *meta, enum kfence_error_type type); void kfence_print_object(struct seq_file *seq, const struct kfence_metadata *meta); diff --git a/mm/kfence/report.c b/mm/kfence/report.c index 64f27c8d46a3..4dbfa9a382e4 100644 --- a/mm/kfence/report.c +++ b/mm/kfence/report.c @@ -10,6 +10,7 @@ #include <linux/kernel.h> #include <linux/lockdep.h> #include <linux/printk.h> +#include <linux/sched/debug.h> #include <linux/seq_file.h> #include <linux/stacktrace.h> #include <linux/string.h> @@ -41,7 +42,6 @@ static int get_stack_skipnr(const unsigned long stack_entries[], int num_entries { char buf[64]; int skipnr, fallback = 0; - bool is_access_fault = false; if (type) { /* Depending on error type, find different stack entries. */ @@ -49,8 +49,12 @@ static int get_stack_skipnr(const unsigned long stack_entries[], int num_entries case KFENCE_ERROR_UAF: case KFENCE_ERROR_OOB: case KFENCE_ERROR_INVALID: - is_access_fault = true; - break; + /* + * kfence_handle_page_fault() may be called with pt_regs + * set to NULL; in that case we'll simply show the full + * stack trace. + */ + return 0; case KFENCE_ERROR_CORRUPTION: case KFENCE_ERROR_INVALID_FREE: break; @@ -60,26 +64,21 @@ static int get_stack_skipnr(const unsigned long stack_entries[], int num_entries for (skipnr = 0; skipnr < num_entries; skipnr++) { int len = scnprintf(buf, sizeof(buf), "%ps", (void *)stack_entries[skipnr]); - if (is_access_fault) { - if (!strncmp(buf, KFENCE_SKIP_ARCH_FAULT_HANDLER, len)) - goto found; - } else { - if (str_has_prefix(buf, "kfence_") || str_has_prefix(buf, "__kfence_") || - !strncmp(buf, "__slab_free", len)) { - /* - * In case of tail calls from any of the below - * to any of the above. - */ - fallback = skipnr + 1; - } - - /* Also the *_bulk() variants by only checking prefixes. */ - if (str_has_prefix(buf, "kfree") || - str_has_prefix(buf, "kmem_cache_free") || - str_has_prefix(buf, "__kmalloc") || - str_has_prefix(buf, "kmem_cache_alloc")) - goto found; + if (str_has_prefix(buf, "kfence_") || str_has_prefix(buf, "__kfence_") || + !strncmp(buf, "__slab_free", len)) { + /* + * In case of tail calls from any of the below + * to any of the above. + */ + fallback = skipnr + 1; } + + /* Also the *_bulk() variants by only checking prefixes. */ + if (str_has_prefix(buf, "kfree") || + str_has_prefix(buf, "kmem_cache_free") || + str_has_prefix(buf, "__kmalloc") || + str_has_prefix(buf, "kmem_cache_alloc")) + goto found; } if (fallback < num_entries) return fallback; @@ -157,13 +156,20 @@ static void print_diff_canary(unsigned long address, size_t bytes_to_show, pr_cont(" ]"); } -void kfence_report_error(unsigned long address, const struct kfence_metadata *meta, - enum kfence_error_type type) +void kfence_report_error(unsigned long address, struct pt_regs *regs, + const struct kfence_metadata *meta, enum kfence_error_type type) { unsigned long stack_entries[KFENCE_STACK_DEPTH] = { 0 }; - int num_stack_entries = stack_trace_save(stack_entries, KFENCE_STACK_DEPTH, 1); - int skipnr = get_stack_skipnr(stack_entries, num_stack_entries, &type); const ptrdiff_t object_index = meta ? meta - kfence_metadata : -1; + int num_stack_entries; + int skipnr = 0; + + if (regs) { + num_stack_entries = stack_trace_save_regs(regs, stack_entries, KFENCE_STACK_DEPTH, 0); + } else { + num_stack_entries = stack_trace_save(stack_entries, KFENCE_STACK_DEPTH, 1); + skipnr = get_stack_skipnr(stack_entries, num_stack_entries, &type); + } /* Require non-NULL meta, except if KFENCE_ERROR_INVALID. */ if (WARN_ON(type != KFENCE_ERROR_INVALID && !meta)) @@ -227,7 +233,10 @@ void kfence_report_error(unsigned long address, const struct kfence_metadata *me /* Print report footer. */ pr_err("\n"); - dump_stack_print_info(KERN_ERR); + if (IS_ENABLED(CONFIG_DEBUG_KERNEL) && regs) + show_regs(regs); + else + dump_stack_print_info(KERN_ERR); pr_err("==================================================================\n"); lockdep_on(); -- 2.25.1

1 0

[PATCH 3/9] arm64, kfence: enable KFENCE for ARM64
by 1415317271＠qq.com 18 Aug '21

18 Aug '21

From: Marco Elver <elver(a)google.com> Add architecture specific implementation details for KFENCE and enable KFENCE for the arm64 architecture. In particular, this implements the required interface in <asm/kfence.h>. KFENCE requires that attributes for pages from its memory pool can individually be set. Therefore, force the entire linear map to be mapped at page granularity. Doing so may result in extra memory allocated for page tables in case rodata=full is not set; however, currently CONFIG_RODATA_FULL_DEFAULT_ENABLED=y is the default, and the common case is therefore not affected by this change. [elver(a)google.com: add missing copyright and description header] Link: https://lkml.kernel.org/r/20210118092159.145934-3-elver@google.com Link: https://lkml.kernel.org/r/20201103175841.3495947-4-elver@google.com Signed-off-by: Alexander Potapenko <glider(a)google.com> Signed-off-by: Marco Elver <elver(a)google.com> Reviewed-by: Dmitry Vyukov <dvyukov(a)google.com> Co-developed-by: Alexander Potapenko <glider(a)google.com> Reviewed-by: Jann Horn <jannh(a)google.com> Reviewed-by: Mark Rutland <mark.rutland(a)arm.com> Cc: Andrey Konovalov <andreyknvl(a)google.com> Cc: Andrey Ryabinin <aryabinin(a)virtuozzo.com> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Catalin Marinas <catalin.marinas(a)arm.com> Cc: Christopher Lameter <cl(a)linux.com> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: David Rientjes <rientjes(a)google.com> Cc: Eric Dumazet <edumazet(a)google.com> Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Cc: Hillf Danton <hdanton(a)sina.com> Cc: "H. Peter Anvin" <hpa(a)zytor.com> Cc: Ingo Molnar <mingo(a)redhat.com> Cc: Joern Engel <joern(a)purestorage.com> Cc: Jonathan Corbet <corbet(a)lwn.net> Cc: Joonsoo Kim <iamjoonsoo.kim(a)lge.com> Cc: Kees Cook <keescook(a)chromium.org> Cc: Paul E. McKenney <paulmck(a)kernel.org> Cc: Pekka Enberg <penberg(a)kernel.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: SeongJae Park <sjpark(a)amazon.de> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: Will Deacon <will(a)kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds(a)linux-foundation.org> Signed-off-by: Yingjie Shang <1415317271(a)qq.com> Reviewed-by: Bixuan Cui <cuibixuan(a)huawei.com> --- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/kfence.h | 24 ++++++++++++++++++++++++ arch/arm64/mm/fault.c | 4 ++++ arch/arm64/mm/mmu.c | 7 ++++++- 4 files changed, 35 insertions(+), 1 deletion(-) create mode 100644 arch/arm64/include/asm/kfence.h diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 109d8a18f268..6331f54b493a 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -138,6 +138,7 @@ config ARM64 select HAVE_ARCH_JUMP_LABEL_RELATIVE select HAVE_ARCH_KASAN if !(ARM64_16K_PAGES && ARM64_VA_BITS_48) select HAVE_ARCH_KASAN_SW_TAGS if HAVE_ARCH_KASAN + select HAVE_ARCH_KFENCE select HAVE_ARCH_KGDB select HAVE_ARCH_MMAP_RND_BITS select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT diff --git a/arch/arm64/include/asm/kfence.h b/arch/arm64/include/asm/kfence.h new file mode 100644 index 000000000000..42a06f83850a --- /dev/null +++ b/arch/arm64/include/asm/kfence.h @@ -0,0 +1,24 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * arm64 KFENCE support. + * + * Copyright (C) 2020, Google LLC. + */ + +#ifndef __ASM_KFENCE_H +#define __ASM_KFENCE_H + +#include <asm/cacheflush.h> + +#define KFENCE_SKIP_ARCH_FAULT_HANDLER "el1_sync" + +static inline bool arch_kfence_init_pool(void) { return true; } + +static inline bool kfence_protect_page(unsigned long addr, bool protect) +{ + set_memory_valid(addr, 1, !protect); + + return true; +} + +#endif /* __ASM_KFENCE_H */ diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index 795d224f184f..d1a8b523d28e 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -10,6 +10,7 @@ #include <linux/acpi.h> #include <linux/bitfield.h> #include <linux/extable.h> +#include <linux/kfence.h> #include <linux/signal.h> #include <linux/mm.h> #include <linux/hardirq.h> @@ -322,6 +323,9 @@ static void __do_kernel_fault(unsigned long addr, unsigned int esr, } else if (addr < PAGE_SIZE) { msg = "NULL pointer dereference"; } else { + if (kfence_handle_page_fault(addr)) + return; + msg = "paging request"; } diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 1ec57fd87ef7..2af6d99a8c2e 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -1452,7 +1452,12 @@ int arch_add_memory(int nid, u64 start, u64 size, return -EINVAL; } - if (rodata_full || debug_pagealloc_enabled()) + /* + * KFENCE requires linear map to be mapped at page granularity, so that + * it is possible to protect/unprotect single pages in the KFENCE pool. + */ + if (rodata_full || debug_pagealloc_enabled() || + IS_ENABLED(CONFIG_KFENCE)) flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; __create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start), -- 2.25.1

1 0

[PATCH 2/9] x86, kfence: enable KFENCE for x86
by 1415317271＠qq.com 18 Aug '21

18 Aug '21

From: Alexander Potapenko <glider(a)google.com> Add architecture specific implementation details for KFENCE and enable KFENCE for the x86 architecture. In particular, this implements the required interface in <asm/kfence.h> for setting up the pool and providing helper functions for protecting and unprotecting pages. For x86, we need to ensure that the pool uses 4K pages, which is done using the set_memory_4k() helper function. [elver(a)google.com: add missing copyright and description header] Link: https://lkml.kernel.org/r/20210118092159.145934-2-elver@google.com Link: https://lkml.kernel.org/r/20201103175841.3495947-3-elver@google.com Signed-off-by: Marco Elver <elver(a)google.com> Signed-off-by: Alexander Potapenko <glider(a)google.com> Reviewed-by: Dmitry Vyukov <dvyukov(a)google.com> Co-developed-by: Marco Elver <elver(a)google.com> Reviewed-by: Jann Horn <jannh(a)google.com> Cc: Andrey Konovalov <andreyknvl(a)google.com> Cc: Andrey Ryabinin <aryabinin(a)virtuozzo.com> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Catalin Marinas <catalin.marinas(a)arm.com> Cc: Christopher Lameter <cl(a)linux.com> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: David Rientjes <rientjes(a)google.com> Cc: Eric Dumazet <edumazet(a)google.com> Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Cc: Hillf Danton <hdanton(a)sina.com> Cc: "H. Peter Anvin" <hpa(a)zytor.com> Cc: Ingo Molnar <mingo(a)redhat.com> Cc: Joern Engel <joern(a)purestorage.com> Cc: Jonathan Corbet <corbet(a)lwn.net> Cc: Joonsoo Kim <iamjoonsoo.kim(a)lge.com> Cc: Kees Cook <keescook(a)chromium.org> Cc: Mark Rutland <mark.rutland(a)arm.com> Cc: Paul E. McKenney <paulmck(a)kernel.org> Cc: Pekka Enberg <penberg(a)kernel.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: SeongJae Park <sjpark(a)amazon.de> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: Will Deacon <will(a)kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds(a)linux-foundation.org> Signed-off-by: Yingjie Shang <1415317271(a)qq.com> Reviewed-by: Bixuan Cui <cuibixuan(a)huawei.com> --- arch/x86/Kconfig | 1 + arch/x86/include/asm/kfence.h | 70 +++++++++++++++++++++++++++++++++++ arch/x86/mm/fault.c | 4 ++ 3 files changed, 75 insertions(+) create mode 100644 arch/x86/include/asm/kfence.h diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index af7123b5b493..37a7b2c8fdd6 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -148,6 +148,7 @@ config X86 select HAVE_ARCH_JUMP_LABEL_RELATIVE select HAVE_ARCH_KASAN if X86_64 select HAVE_ARCH_KASAN_VMALLOC if X86_64 + select HAVE_ARCH_KFENCE select HAVE_ARCH_KGDB select HAVE_ARCH_MMAP_RND_BITS if MMU select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT diff --git a/arch/x86/include/asm/kfence.h b/arch/x86/include/asm/kfence.h new file mode 100644 index 000000000000..a0659dbd93ea --- /dev/null +++ b/arch/x86/include/asm/kfence.h @@ -0,0 +1,70 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * x86 KFENCE support. + * + * Copyright (C) 2020, Google LLC. + */ + +#ifndef _ASM_X86_KFENCE_H +#define _ASM_X86_KFENCE_H + +#include <linux/bug.h> +#include <linux/kfence.h> + +#include <asm/pgalloc.h> +#include <asm/pgtable.h> +#include <asm/set_memory.h> +#include <asm/tlbflush.h> + +/* + * The page fault handler entry function, up to which the stack trace is + * truncated in reports. + */ +#define KFENCE_SKIP_ARCH_FAULT_HANDLER "asm_exc_page_fault" + +/* Force 4K pages for __kfence_pool. */ +static inline bool arch_kfence_init_pool(void) +{ + unsigned long addr; + + for (addr = (unsigned long)__kfence_pool; is_kfence_address((void *)addr); + addr += PAGE_SIZE) { + unsigned int level; + + if (!lookup_address(addr, &level)) + return false; + + if (level != PG_LEVEL_4K) + set_memory_4k(addr, 1); + } + + return true; +} + +/* Protect the given page and flush TLB. */ +static inline bool kfence_protect_page(unsigned long addr, bool protect) +{ + unsigned int level; + pte_t *pte = lookup_address(addr, &level); + + if (WARN_ON(!pte || level != PG_LEVEL_4K)) + return false; + + /* + * We need to avoid IPIs, as we may get KFENCE allocations or faults + * with interrupts disabled. Therefore, the below is best-effort, and + * does not flush TLBs on all CPUs. We can tolerate some inaccuracy; + * lazy fault handling takes care of faults after the page is PRESENT. + */ + + if (protect) + set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_PRESENT)); + else + set_pte(pte, __pte(pte_val(*pte) | _PAGE_PRESENT)); + + /* Flush this CPU's TLB. */ + flush_tlb_one_kernel(addr); + return true; +} + +#endif /* _ASM_X86_KFENCE_H */ diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 9c1545c376e9..35901aa6ad1c 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -9,6 +9,7 @@ #include <linux/kdebug.h> /* oops_begin/end, ... */ #include <linux/extable.h> /* search_exception_tables */ #include <linux/memblock.h> /* max_low_pfn */ +#include <linux/kfence.h> /* kfence_handle_page_fault */ #include <linux/kprobes.h> /* NOKPROBE_SYMBOL, ... */ #include <linux/mmiotrace.h> /* kmmio_handler, ... */ #include <linux/perf_event.h> /* perf_sw_event */ @@ -732,6 +733,9 @@ no_context(struct pt_regs *regs, unsigned long error_code, if (IS_ENABLED(CONFIG_EFI)) efi_recover_from_page_fault(address); + /* Only not-present faults should be handled by KFENCE. */ + if (!(error_code & X86_PF_PROT) && kfence_handle_page_fault(address)) + return; oops: /* * Oops. The kernel tried to access some bad page. We'll have to -- 2.25.1

1 0

[PATCH 1/9] mm: add Kernel Electric-Fence infrastructure
by 1415317271＠qq.com 18 Aug '21

18 Aug '21

From: Alexander Potapenko <glider(a)google.com> Patch series "KFENCE: A low-overhead sampling-based memory safety error detector", v7. This adds the Kernel Electric-Fence (KFENCE) infrastructure. KFENCE is a low-overhead sampling-based memory safety error detector of heap use-after-free, invalid-free, and out-of-bounds access errors. This series enables KFENCE for the x86 and arm64 architectures, and adds KFENCE hooks to the SLAB and SLUB allocators. KFENCE is designed to be enabled in production kernels, and has near zero performance overhead. Compared to KASAN, KFENCE trades performance for precision. The main motivation behind KFENCE's design, is that with enough total uptime KFENCE will detect bugs in code paths not typically exercised by non-production test workloads. One way to quickly achieve a large enough total uptime is when the tool is deployed across a large fleet of machines. KFENCE objects each reside on a dedicated page, at either the left or right page boundaries. The pages to the left and right of the object page are "guard pages", whose attributes are changed to a protected state, and cause page faults on any attempted access to them. Such page faults are then intercepted by KFENCE, which handles the fault gracefully by reporting a memory access error. Guarded allocations are set up based on a sample interval (can be set via kfence.sample_interval). After expiration of the sample interval, the next allocation through the main allocator (SLAB or SLUB) returns a guarded allocation from the KFENCE object pool. At this point, the timer is reset, and the next allocation is set up after the expiration of the interval. To enable/disable a KFENCE allocation through the main allocator's fast-path without overhead, KFENCE relies on static branches via the static keys infrastructure. The static branch is toggled to redirect the allocation to KFENCE. The KFENCE memory pool is of fixed size, and if the pool is exhausted no further KFENCE allocations occur. The default config is conservative with only 255 objects, resulting in a pool size of 2 MiB (with 4 KiB pages). We have verified by running synthetic benchmarks (sysbench I/O, hackbench) and production server-workload benchmarks that a kernel with KFENCE (using sample intervals 100-500ms) is performance-neutral compared to a non-KFENCE baseline kernel. KFENCE is inspired by GWP-ASan [1], a userspace tool with similar properties. The name "KFENCE" is a homage to the Electric Fence Malloc Debugger [2]. For more details, see Documentation/dev-tools/kfence.rst added in the series -- also viewable here: https://raw.githubusercontent.com/google/kasan/kfence/Documentation/dev-too… [1] http://llvm.org/docs/GwpAsan.html [2] https://linux.die.net/man/3/efence This patch (of 9): This adds the Kernel Electric-Fence (KFENCE) infrastructure. KFENCE is a low-overhead sampling-based memory safety error detector of heap use-after-free, invalid-free, and out-of-bounds access errors. KFENCE is designed to be enabled in production kernels, and has near zero performance overhead. Compared to KASAN, KFENCE trades performance for precision. The main motivation behind KFENCE's design, is that with enough total uptime KFENCE will detect bugs in code paths not typically exercised by non-production test workloads. One way to quickly achieve a large enough total uptime is when the tool is deployed across a large fleet of machines. KFENCE objects each reside on a dedicated page, at either the left or right page boundaries. The pages to the left and right of the object page are "guard pages", whose attributes are changed to a protected state, and cause page faults on any attempted access to them. Such page faults are then intercepted by KFENCE, which handles the fault gracefully by reporting a memory access error. To detect out-of-bounds writes to memory within the object's page itself, KFENCE also uses pattern-based redzones. The following figure illustrates the page layout: ---+-----------+-----------+-----------+-----------+-----------+--- | xxxxxxxxx | O : | xxxxxxxxx | : O | xxxxxxxxx | | xxxxxxxxx | B : | xxxxxxxxx | : B | xxxxxxxxx | | x GUARD x | J : RED- | x GUARD x | RED- : J | x GUARD x | | xxxxxxxxx | E : ZONE | xxxxxxxxx | ZONE : E | xxxxxxxxx | | xxxxxxxxx | C : | xxxxxxxxx | : C | xxxxxxxxx | | xxxxxxxxx | T : | xxxxxxxxx | : T | xxxxxxxxx | ---+-----------+-----------+-----------+-----------+-----------+--- Guarded allocations are set up based on a sample interval (can be set via kfence.sample_interval). After expiration of the sample interval, a guarded allocation from the KFENCE object pool is returned to the main allocator (SLAB or SLUB). At this point, the timer is reset, and the next allocation is set up after the expiration of the interval. To enable/disable a KFENCE allocation through the main allocator's fast-path without overhead, KFENCE relies on static branches via the static keys infrastructure. The static branch is toggled to redirect the allocation to KFENCE. To date, we have verified by running synthetic benchmarks (sysbench I/O, hackbench) that a kernel compiled with KFENCE is performance-neutral compared to the non-KFENCE baseline. For more details, see Documentation/dev-tools/kfence.rst (added later in the series). [elver(a)google.com: fix parameter description for kfence_object_start()] Link: https://lkml.kernel.org/r/20201106092149.GA2851373@elver.google.com [elver(a)google.com: avoid stalling work queue task without allocations] Link: https://lkml.kernel.org/r/CADYN=9J0DQhizAGB0-jz4HOBBh+05kMBXb4c0cXMS7Qi5NAJ… Link: https://lkml.kernel.org/r/20201110135320.3309507-1-elver@google.com [elver(a)google.com: fix potential deadlock due to wake_up()] Link: https://lkml.kernel.org/r/000000000000c0645805b7f982e4@google.com Link: https://lkml.kernel.org/r/20210104130749.1768991-1-elver@google.com [elver(a)google.com: add option to use KFENCE without static keys] Link: https://lkml.kernel.org/r/20210111091544.3287013-1-elver@google.com [elver(a)google.com: add missing copyright and description headers] Link: https://lkml.kernel.org/r/20210118092159.145934-1-elver@google.com Link: https://lkml.kernel.org/r/20201103175841.3495947-2-elver@google.com Signed-off-by: Marco Elver <elver(a)google.com> Signed-off-by: Alexander Potapenko <glider(a)google.com> Reviewed-by: Dmitry Vyukov <dvyukov(a)google.com> Reviewed-by: SeongJae Park <sjpark(a)amazon.de> Co-developed-by: Marco Elver <elver(a)google.com> Reviewed-by: Jann Horn <jannh(a)google.com> Cc: "H. Peter Anvin" <hpa(a)zytor.com> Cc: Paul E. McKenney <paulmck(a)kernel.org> Cc: Andrey Konovalov <andreyknvl(a)google.com> Cc: Andrey Ryabinin <aryabinin(a)virtuozzo.com> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Catalin Marinas <catalin.marinas(a)arm.com> Cc: Christopher Lameter <cl(a)linux.com> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: David Rientjes <rientjes(a)google.com> Cc: Eric Dumazet <edumazet(a)google.com> Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Cc: Hillf Danton <hdanton(a)sina.com> Cc: Ingo Molnar <mingo(a)redhat.com> Cc: Jonathan Corbet <corbet(a)lwn.net> Cc: Joonsoo Kim <iamjoonsoo.kim(a)lge.com> Cc: Joern Engel <joern(a)purestorage.com> Cc: Kees Cook <keescook(a)chromium.org> Cc: Mark Rutland <mark.rutland(a)arm.com> Cc: Pekka Enberg <penberg(a)kernel.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: Will Deacon <will(a)kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds(a)linux-foundation.org> Signed-off-by: Yingjie Shang <1415317271(a)qq.com> Reviewed-by: Bixuan Cui <cuibixuan(a)huawei.com> --- include/linux/kfence.h | 216 +++++++++++ init/main.c | 3 + lib/Kconfig.debug | 1 + lib/Kconfig.kfence | 67 ++++ mm/Makefile | 1 + mm/kfence/Makefile | 3 + mm/kfence/core.c | 840 +++++++++++++++++++++++++++++++++++++++++ mm/kfence/kfence.h | 113 ++++++ mm/kfence/report.c | 240 ++++++++++++ 9 files changed, 1484 insertions(+) create mode 100644 include/linux/kfence.h create mode 100644 lib/Kconfig.kfence create mode 100644 mm/kfence/Makefile create mode 100644 mm/kfence/core.c create mode 100644 mm/kfence/kfence.h create mode 100644 mm/kfence/report.c diff --git a/include/linux/kfence.h b/include/linux/kfence.h new file mode 100644 index 000000000000..81f3911cb298 --- /dev/null +++ b/include/linux/kfence.h @@ -0,0 +1,216 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Kernel Electric-Fence (KFENCE). Public interface for allocator and fault + * handler integration. For more info see Documentation/dev-tools/kfence.rst. + * + * Copyright (C) 2020, Google LLC. + */ + +#ifndef _LINUX_KFENCE_H +#define _LINUX_KFENCE_H + +#include <linux/mm.h> +#include <linux/types.h> + +#ifdef CONFIG_KFENCE + +/* + * We allocate an even number of pages, as it simplifies calculations to map + * address to metadata indices; effectively, the very first page serves as an + * extended guard page, but otherwise has no special purpose. + */ +#define KFENCE_POOL_SIZE ((CONFIG_KFENCE_NUM_OBJECTS + 1) * 2 * PAGE_SIZE) +extern char *__kfence_pool; + +#ifdef CONFIG_KFENCE_STATIC_KEYS +#include <linux/static_key.h> +DECLARE_STATIC_KEY_FALSE(kfence_allocation_key); +#else +#include <linux/atomic.h> +extern atomic_t kfence_allocation_gate; +#endif + +/** + * is_kfence_address() - check if an address belongs to KFENCE pool + * @addr: address to check + * + * Return: true or false depending on whether the address is within the KFENCE + * object range. + * + * KFENCE objects live in a separate page range and are not to be intermixed + * with regular heap objects (e.g. KFENCE objects must never be added to the + * allocator freelists). Failing to do so may and will result in heap + * corruptions, therefore is_kfence_address() must be used to check whether + * an object requires specific handling. + * + * Note: This function may be used in fast-paths, and is performance critical. + * Future changes should take this into account; for instance, we want to avoid + * introducing another load and therefore need to keep KFENCE_POOL_SIZE a + * constant (until immediate patching support is added to the kernel). + */ +static __always_inline bool is_kfence_address(const void *addr) +{ + /* + * The non-NULL check is required in case the __kfence_pool pointer was + * never initialized; keep it in the slow-path after the range-check. + */ + return unlikely((unsigned long)((char *)addr - __kfence_pool) < KFENCE_POOL_SIZE && addr); +} + +/** + * kfence_alloc_pool() - allocate the KFENCE pool via memblock + */ +void __init kfence_alloc_pool(void); + +/** + * kfence_init() - perform KFENCE initialization at boot time + * + * Requires that kfence_alloc_pool() was called before. This sets up the + * allocation gate timer, and requires that workqueues are available. + */ +void __init kfence_init(void); + +/** + * kfence_shutdown_cache() - handle shutdown_cache() for KFENCE objects + * @s: cache being shut down + * + * Before shutting down a cache, one must ensure there are no remaining objects + * allocated from it. Because KFENCE objects are not referenced from the cache + * directly, we need to check them here. + * + * Note that shutdown_cache() is internal to SL*B, and kmem_cache_destroy() does + * not return if allocated objects still exist: it prints an error message and + * simply aborts destruction of a cache, leaking memory. + * + * If the only such objects are KFENCE objects, we will not leak the entire + * cache, but instead try to provide more useful debug info by making allocated + * objects "zombie allocations". Objects may then still be used or freed (which + * is handled gracefully), but usage will result in showing KFENCE error reports + * which include stack traces to the user of the object, the original allocation + * site, and caller to shutdown_cache(). + */ +void kfence_shutdown_cache(struct kmem_cache *s); + +/* + * Allocate a KFENCE object. Allocators must not call this function directly, + * use kfence_alloc() instead. + */ +void *__kfence_alloc(struct kmem_cache *s, size_t size, gfp_t flags); + +/** + * kfence_alloc() - allocate a KFENCE object with a low probability + * @s: struct kmem_cache with object requirements + * @size: exact size of the object to allocate (can be less than @s->size + * e.g. for kmalloc caches) + * @flags: GFP flags + * + * Return: + * * NULL - must proceed with allocating as usual, + * * non-NULL - pointer to a KFENCE object. + * + * kfence_alloc() should be inserted into the heap allocation fast path, + * allowing it to transparently return KFENCE-allocated objects with a low + * probability using a static branch (the probability is controlled by the + * kfence.sample_interval boot parameter). + */ +static __always_inline void *kfence_alloc(struct kmem_cache *s, size_t size, gfp_t flags) +{ +#ifdef CONFIG_KFENCE_STATIC_KEYS + if (static_branch_unlikely(&kfence_allocation_key)) +#else + if (unlikely(!atomic_read(&kfence_allocation_gate))) +#endif + return __kfence_alloc(s, size, flags); + return NULL; +} + +/** + * kfence_ksize() - get actual amount of memory allocated for a KFENCE object + * @addr: pointer to a heap object + * + * Return: + * * 0 - not a KFENCE object, must call __ksize() instead, + * * non-0 - this many bytes can be accessed without causing a memory error. + * + * kfence_ksize() returns the number of bytes requested for a KFENCE object at + * allocation time. This number may be less than the object size of the + * corresponding struct kmem_cache. + */ +size_t kfence_ksize(const void *addr); + +/** + * kfence_object_start() - find the beginning of a KFENCE object + * @addr: address within a KFENCE-allocated object + * + * Return: address of the beginning of the object. + * + * SL[AU]B-allocated objects are laid out within a page one by one, so it is + * easy to calculate the beginning of an object given a pointer inside it and + * the object size. The same is not true for KFENCE, which places a single + * object at either end of the page. This helper function is used to find the + * beginning of a KFENCE-allocated object. + */ +void *kfence_object_start(const void *addr); + +/** + * __kfence_free() - release a KFENCE heap object to KFENCE pool + * @addr: object to be freed + * + * Requires: is_kfence_address(addr) + * + * Release a KFENCE object and mark it as freed. + */ +void __kfence_free(void *addr); + +/** + * kfence_free() - try to release an arbitrary heap object to KFENCE pool + * @addr: object to be freed + * + * Return: + * * false - object doesn't belong to KFENCE pool and was ignored, + * * true - object was released to KFENCE pool. + * + * Release a KFENCE object and mark it as freed. May be called on any object, + * even non-KFENCE objects, to simplify integration of the hooks into the + * allocator's free codepath. The allocator must check the return value to + * determine if it was a KFENCE object or not. + */ +static __always_inline __must_check bool kfence_free(void *addr) +{ + if (!is_kfence_address(addr)) + return false; + __kfence_free(addr); + return true; +} + +/** + * kfence_handle_page_fault() - perform page fault handling for KFENCE pages + * @addr: faulting address + * + * Return: + * * false - address outside KFENCE pool, + * * true - page fault handled by KFENCE, no additional handling required. + * + * A page fault inside KFENCE pool indicates a memory error, such as an + * out-of-bounds access, a use-after-free or an invalid memory access. In these + * cases KFENCE prints an error message and marks the offending page as + * present, so that the kernel can proceed. + */ +bool __must_check kfence_handle_page_fault(unsigned long addr); + +#else /* CONFIG_KFENCE */ + +static inline bool is_kfence_address(const void *addr) { return false; } +static inline void kfence_alloc_pool(void) { } +static inline void kfence_init(void) { } +static inline void kfence_shutdown_cache(struct kmem_cache *s) { } +static inline void *kfence_alloc(struct kmem_cache *s, size_t size, gfp_t flags) { return NULL; } +static inline size_t kfence_ksize(const void *addr) { return 0; } +static inline void *kfence_object_start(const void *addr) { return NULL; } +static inline void __kfence_free(void *addr) { } +static inline bool __must_check kfence_free(void *addr) { return false; } +static inline bool __must_check kfence_handle_page_fault(unsigned long addr) { return false; } + +#endif + +#endif /* _LINUX_KFENCE_H */ diff --git a/init/main.c b/init/main.c index fc0277a9e7a3..2d027dc11b10 100644 --- a/init/main.c +++ b/init/main.c @@ -40,6 +40,7 @@ #include <linux/security.h> #include <linux/smp.h> #include <linux/profile.h> +#include <linux/kfence.h> #include <linux/rcupdate.h> #include <linux/moduleparam.h> #include <linux/kallsyms.h> @@ -828,6 +829,7 @@ static void __init mm_init(void) */ page_ext_init_flatmem(); init_debug_pagealloc(); + kfence_alloc_pool(); report_meminit(); mem_init(); kmem_cache_init(); @@ -956,6 +958,7 @@ asmlinkage __visible void __init __no_sanitize_address start_kernel(void) hrtimers_init(); softirq_init(); timekeeping_init(); + kfence_init(); /* * For best initial stack canary entropy, prepare it after: diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 799e49a29797..29e64b4cd412 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -878,6 +878,7 @@ config DEBUG_STACKOVERFLOW If in doubt, say "N". source "lib/Kconfig.kasan" +source "lib/Kconfig.kfence" endmenu # "Memory Debugging" diff --git a/lib/Kconfig.kfence b/lib/Kconfig.kfence new file mode 100644 index 000000000000..b88ac9d6b2e6 --- /dev/null +++ b/lib/Kconfig.kfence @@ -0,0 +1,67 @@ +# SPDX-License-Identifier: GPL-2.0-only + +config HAVE_ARCH_KFENCE + bool + +menuconfig KFENCE + bool "KFENCE: low-overhead sampling-based memory safety error detector" + depends on HAVE_ARCH_KFENCE && !KASAN && (SLAB || SLUB) + select STACKTRACE + help + KFENCE is a low-overhead sampling-based detector of heap out-of-bounds + access, use-after-free, and invalid-free errors. KFENCE is designed + to have negligible cost to permit enabling it in production + environments. + + Note that, KFENCE is not a substitute for explicit testing with tools + such as KASAN. KFENCE can detect a subset of bugs that KASAN can + detect, albeit at very different performance profiles. If you can + afford to use KASAN, continue using KASAN, for example in test + environments. If your kernel targets production use, and cannot + enable KASAN due to its cost, consider using KFENCE. + +if KFENCE + +config KFENCE_STATIC_KEYS + bool "Use static keys to set up allocations" + default y + depends on JUMP_LABEL # To ensure performance, require jump labels + help + Use static keys (static branches) to set up KFENCE allocations. Using + static keys is normally recommended, because it avoids a dynamic + branch in the allocator's fast path. However, with very low sample + intervals, or on systems that do not support jump labels, a dynamic + branch may still be an acceptable performance trade-off. + +config KFENCE_SAMPLE_INTERVAL + int "Default sample interval in milliseconds" + default 100 + help + The KFENCE sample interval determines the frequency with which heap + allocations will be guarded by KFENCE. May be overridden via boot + parameter "kfence.sample_interval". + + Set this to 0 to disable KFENCE by default, in which case only + setting "kfence.sample_interval" to a non-zero value enables KFENCE. + +config KFENCE_NUM_OBJECTS + int "Number of guarded objects available" + range 1 65535 + default 255 + help + The number of guarded objects available. For each KFENCE object, 2 + pages are required; with one containing the object and two adjacent + ones used as guard pages. + +config KFENCE_STRESS_TEST_FAULTS + int "Stress testing of fault handling and error reporting" if EXPERT + default 0 + help + The inverse probability with which to randomly protect KFENCE object + pages, resulting in spurious use-after-frees. The main purpose of + this option is to stress test KFENCE with concurrent error reports + and allocations/frees. A value of 0 disables stress testing logic. + + Only for KFENCE testing; set to 0 if you are not a KFENCE developer. + +endif # KFENCE diff --git a/mm/Makefile b/mm/Makefile index 2b1991759835..3d81a67d66a2 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -82,6 +82,7 @@ obj-$(CONFIG_PAGE_POISONING) += page_poison.o obj-$(CONFIG_SLAB) += slab.o obj-$(CONFIG_SLUB) += slub.o obj-$(CONFIG_KASAN) += kasan/ +obj-$(CONFIG_KFENCE) += kfence/ obj-$(CONFIG_FAILSLAB) += failslab.o obj-$(CONFIG_MEMORY_HOTPLUG) += memory_hotplug.o obj-$(CONFIG_MEMTEST) += memtest.o diff --git a/mm/kfence/Makefile b/mm/kfence/Makefile new file mode 100644 index 000000000000..d991e9a349f0 --- /dev/null +++ b/mm/kfence/Makefile @@ -0,0 +1,3 @@ +# SPDX-License-Identifier: GPL-2.0 + +obj-$(CONFIG_KFENCE) := core.o report.o diff --git a/mm/kfence/core.c b/mm/kfence/core.c new file mode 100644 index 000000000000..d6a32c13336b --- /dev/null +++ b/mm/kfence/core.c @@ -0,0 +1,840 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KFENCE guarded object allocator and fault handling. + * + * Copyright (C) 2020, Google LLC. + */ + +#define pr_fmt(fmt) "kfence: " fmt + +#include <linux/atomic.h> +#include <linux/bug.h> +#include <linux/debugfs.h> +#include <linux/kcsan-checks.h> +#include <linux/kfence.h> +#include <linux/list.h> +#include <linux/lockdep.h> +#include <linux/memblock.h> +#include <linux/moduleparam.h> +#include <linux/random.h> +#include <linux/rcupdate.h> +#include <linux/seq_file.h> +#include <linux/slab.h> +#include <linux/spinlock.h> +#include <linux/string.h> + +#include <asm/kfence.h> + +#include "kfence.h" + +/* Disables KFENCE on the first warning assuming an irrecoverable error. */ +#define KFENCE_WARN_ON(cond) \ + ({ \ + const bool __cond = WARN_ON(cond); \ + if (unlikely(__cond)) \ + WRITE_ONCE(kfence_enabled, false); \ + __cond; \ + }) + +/* === Data ================================================================= */ + +static bool kfence_enabled __read_mostly; + +static unsigned long kfence_sample_interval __read_mostly = CONFIG_KFENCE_SAMPLE_INTERVAL; + +#ifdef MODULE_PARAM_PREFIX +#undef MODULE_PARAM_PREFIX +#endif +#define MODULE_PARAM_PREFIX "kfence." + +static int param_set_sample_interval(const char *val, const struct kernel_param *kp) +{ + unsigned long num; + int ret = kstrtoul(val, 0, &num); + + if (ret < 0) + return ret; + + if (!num) /* Using 0 to indicate KFENCE is disabled. */ + WRITE_ONCE(kfence_enabled, false); + else if (!READ_ONCE(kfence_enabled) && system_state != SYSTEM_BOOTING) + return -EINVAL; /* Cannot (re-)enable KFENCE on-the-fly. */ + + *((unsigned long *)kp->arg) = num; + return 0; +} + +static int param_get_sample_interval(char *buffer, const struct kernel_param *kp) +{ + if (!READ_ONCE(kfence_enabled)) + return sprintf(buffer, "0\n"); + + return param_get_ulong(buffer, kp); +} + +static const struct kernel_param_ops sample_interval_param_ops = { + .set = param_set_sample_interval, + .get = param_get_sample_interval, +}; +module_param_cb(sample_interval, &sample_interval_param_ops, &kfence_sample_interval, 0600); + +/* The pool of pages used for guard pages and objects. */ +char *__kfence_pool __ro_after_init; +EXPORT_SYMBOL(__kfence_pool); /* Export for test modules. */ + +/* + * Per-object metadata, with one-to-one mapping of object metadata to + * backing pages (in __kfence_pool). + */ +static_assert(CONFIG_KFENCE_NUM_OBJECTS > 0); +struct kfence_metadata kfence_metadata[CONFIG_KFENCE_NUM_OBJECTS]; + +/* Freelist with available objects. */ +static struct list_head kfence_freelist = LIST_HEAD_INIT(kfence_freelist); +static DEFINE_RAW_SPINLOCK(kfence_freelist_lock); /* Lock protecting freelist. */ + +#ifdef CONFIG_KFENCE_STATIC_KEYS +/* The static key to set up a KFENCE allocation. */ +DEFINE_STATIC_KEY_FALSE(kfence_allocation_key); +#endif + +/* Gates the allocation, ensuring only one succeeds in a given period. */ +atomic_t kfence_allocation_gate = ATOMIC_INIT(1); + +/* Statistics counters for debugfs. */ +enum kfence_counter_id { + KFENCE_COUNTER_ALLOCATED, + KFENCE_COUNTER_ALLOCS, + KFENCE_COUNTER_FREES, + KFENCE_COUNTER_ZOMBIES, + KFENCE_COUNTER_BUGS, + KFENCE_COUNTER_COUNT, +}; +static atomic_long_t counters[KFENCE_COUNTER_COUNT]; +static const char *const counter_names[] = { + [KFENCE_COUNTER_ALLOCATED] = "currently allocated", + [KFENCE_COUNTER_ALLOCS] = "total allocations", + [KFENCE_COUNTER_FREES] = "total frees", + [KFENCE_COUNTER_ZOMBIES] = "zombie allocations", + [KFENCE_COUNTER_BUGS] = "total bugs", +}; +static_assert(ARRAY_SIZE(counter_names) == KFENCE_COUNTER_COUNT); + +/* === Internals ============================================================ */ + +static bool kfence_protect(unsigned long addr) +{ + return !KFENCE_WARN_ON(!kfence_protect_page(ALIGN_DOWN(addr, PAGE_SIZE), true)); +} + +static bool kfence_unprotect(unsigned long addr) +{ + return !KFENCE_WARN_ON(!kfence_protect_page(ALIGN_DOWN(addr, PAGE_SIZE), false)); +} + +static inline struct kfence_metadata *addr_to_metadata(unsigned long addr) +{ + long index; + + /* The checks do not affect performance; only called from slow-paths. */ + + if (!is_kfence_address((void *)addr)) + return NULL; + + /* + * May be an invalid index if called with an address at the edge of + * __kfence_pool, in which case we would report an "invalid access" + * error. + */ + index = (addr - (unsigned long)__kfence_pool) / (PAGE_SIZE * 2) - 1; + if (index < 0 || index >= CONFIG_KFENCE_NUM_OBJECTS) + return NULL; + + return &kfence_metadata[index]; +} + +static inline unsigned long metadata_to_pageaddr(const struct kfence_metadata *meta) +{ + unsigned long offset = (meta - kfence_metadata + 1) * PAGE_SIZE * 2; + unsigned long pageaddr = (unsigned long)&__kfence_pool[offset]; + + /* The checks do not affect performance; only called from slow-paths. */ + + /* Only call with a pointer into kfence_metadata. */ + if (KFENCE_WARN_ON(meta < kfence_metadata || + meta >= kfence_metadata + CONFIG_KFENCE_NUM_OBJECTS)) + return 0; + + /* + * This metadata object only ever maps to 1 page; verify that the stored + * address is in the expected range. + */ + if (KFENCE_WARN_ON(ALIGN_DOWN(meta->addr, PAGE_SIZE) != pageaddr)) + return 0; + + return pageaddr; +} + +/* + * Update the object's metadata state, including updating the alloc/free stacks + * depending on the state transition. + */ +static noinline void metadata_update_state(struct kfence_metadata *meta, + enum kfence_object_state next) +{ + struct kfence_track *track = + next == KFENCE_OBJECT_FREED ? &meta->free_track : &meta->alloc_track; + + lockdep_assert_held(&meta->lock); + + /* + * Skip over 1 (this) functions; noinline ensures we do not accidentally + * skip over the caller by never inlining. + */ + track->num_stack_entries = stack_trace_save(track->stack_entries, KFENCE_STACK_DEPTH, 1); + track->pid = task_pid_nr(current); + + /* + * Pairs with READ_ONCE() in + * kfence_shutdown_cache(), + * kfence_handle_page_fault(). + */ + WRITE_ONCE(meta->state, next); +} + +/* Write canary byte to @addr. */ +static inline bool set_canary_byte(u8 *addr) +{ + *addr = KFENCE_CANARY_PATTERN(addr); + return true; +} + +/* Check canary byte at @addr. */ +static inline bool check_canary_byte(u8 *addr) +{ + if (likely(*addr == KFENCE_CANARY_PATTERN(addr))) + return true; + + atomic_long_inc(&counters[KFENCE_COUNTER_BUGS]); + kfence_report_error((unsigned long)addr, addr_to_metadata((unsigned long)addr), + KFENCE_ERROR_CORRUPTION); + return false; +} + +/* __always_inline this to ensure we won't do an indirect call to fn. */ +static __always_inline void for_each_canary(const struct kfence_metadata *meta, bool (*fn)(u8 *)) +{ + const unsigned long pageaddr = ALIGN_DOWN(meta->addr, PAGE_SIZE); + unsigned long addr; + + lockdep_assert_held(&meta->lock); + + /* + * We'll iterate over each canary byte per-side until fn() returns + * false. However, we'll still iterate over the canary bytes to the + * right of the object even if there was an error in the canary bytes to + * the left of the object. Specifically, if check_canary_byte() + * generates an error, showing both sides might give more clues as to + * what the error is about when displaying which bytes were corrupted. + */ + + /* Apply to left of object. */ + for (addr = pageaddr; addr < meta->addr; addr++) { + if (!fn((u8 *)addr)) + break; + } + + /* Apply to right of object. */ + for (addr = meta->addr + meta->size; addr < pageaddr + PAGE_SIZE; addr++) { + if (!fn((u8 *)addr)) + break; + } +} + +static void *kfence_guarded_alloc(struct kmem_cache *cache, size_t size, gfp_t gfp) +{ + struct kfence_metadata *meta = NULL; + unsigned long flags; + struct page *page; + void *addr; + + /* Try to obtain a free object. */ + raw_spin_lock_irqsave(&kfence_freelist_lock, flags); + if (!list_empty(&kfence_freelist)) { + meta = list_entry(kfence_freelist.next, struct kfence_metadata, list); + list_del_init(&meta->list); + } + raw_spin_unlock_irqrestore(&kfence_freelist_lock, flags); + if (!meta) + return NULL; + + if (unlikely(!raw_spin_trylock_irqsave(&meta->lock, flags))) { + /* + * This is extremely unlikely -- we are reporting on a + * use-after-free, which locked meta->lock, and the reporting + * code via printk calls kmalloc() which ends up in + * kfence_alloc() and tries to grab the same object that we're + * reporting on. While it has never been observed, lockdep does + * report that there is a possibility of deadlock. Fix it by + * using trylock and bailing out gracefully. + */ + raw_spin_lock_irqsave(&kfence_freelist_lock, flags); + /* Put the object back on the freelist. */ + list_add_tail(&meta->list, &kfence_freelist); + raw_spin_unlock_irqrestore(&kfence_freelist_lock, flags); + + return NULL; + } + + meta->addr = metadata_to_pageaddr(meta); + /* Unprotect if we're reusing this page. */ + if (meta->state == KFENCE_OBJECT_FREED) + kfence_unprotect(meta->addr); + + /* + * Note: for allocations made before RNG initialization, will always + * return zero. We still benefit from enabling KFENCE as early as + * possible, even when the RNG is not yet available, as this will allow + * KFENCE to detect bugs due to earlier allocations. The only downside + * is that the out-of-bounds accesses detected are deterministic for + * such allocations. + */ + if (prandom_u32_max(2)) { + /* Allocate on the "right" side, re-calculate address. */ + meta->addr += PAGE_SIZE - size; + meta->addr = ALIGN_DOWN(meta->addr, cache->align); + } + + addr = (void *)meta->addr; + + /* Update remaining metadata. */ + metadata_update_state(meta, KFENCE_OBJECT_ALLOCATED); + /* Pairs with READ_ONCE() in kfence_shutdown_cache(). */ + WRITE_ONCE(meta->cache, cache); + meta->size = size; + for_each_canary(meta, set_canary_byte); + + /* Set required struct page fields. */ + page = virt_to_page(meta->addr); + page->slab_cache = cache; + + raw_spin_unlock_irqrestore(&meta->lock, flags); + + /* Memory initialization. */ + + /* + * We check slab_want_init_on_alloc() ourselves, rather than letting + * SL*B do the initialization, as otherwise we might overwrite KFENCE's + * redzone. + */ + if (unlikely(slab_want_init_on_alloc(gfp, cache))) + memzero_explicit(addr, size); + if (cache->ctor) + cache->ctor(addr); + + if (CONFIG_KFENCE_STRESS_TEST_FAULTS && !prandom_u32_max(CONFIG_KFENCE_STRESS_TEST_FAULTS)) + kfence_protect(meta->addr); /* Random "faults" by protecting the object. */ + + atomic_long_inc(&counters[KFENCE_COUNTER_ALLOCATED]); + atomic_long_inc(&counters[KFENCE_COUNTER_ALLOCS]); + + return addr; +} + +static void kfence_guarded_free(void *addr, struct kfence_metadata *meta, bool zombie) +{ + struct kcsan_scoped_access assert_page_exclusive; + unsigned long flags; + + raw_spin_lock_irqsave(&meta->lock, flags); + + if (meta->state != KFENCE_OBJECT_ALLOCATED || meta->addr != (unsigned long)addr) { + /* Invalid or double-free, bail out. */ + atomic_long_inc(&counters[KFENCE_COUNTER_BUGS]); + kfence_report_error((unsigned long)addr, meta, KFENCE_ERROR_INVALID_FREE); + raw_spin_unlock_irqrestore(&meta->lock, flags); + return; + } + + /* Detect racy use-after-free, or incorrect reallocation of this page by KFENCE. */ + kcsan_begin_scoped_access((void *)ALIGN_DOWN((unsigned long)addr, PAGE_SIZE), PAGE_SIZE, + KCSAN_ACCESS_SCOPED | KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ASSERT, + &assert_page_exclusive); + + if (CONFIG_KFENCE_STRESS_TEST_FAULTS) + kfence_unprotect((unsigned long)addr); /* To check canary bytes. */ + + /* Restore page protection if there was an OOB access. */ + if (meta->unprotected_page) { + kfence_protect(meta->unprotected_page); + meta->unprotected_page = 0; + } + + /* Check canary bytes for memory corruption. */ + for_each_canary(meta, check_canary_byte); + + /* + * Clear memory if init-on-free is set. While we protect the page, the + * data is still there, and after a use-after-free is detected, we + * unprotect the page, so the data is still accessible. + */ + if (!zombie && unlikely(slab_want_init_on_free(meta->cache))) + memzero_explicit(addr, meta->size); + + /* Mark the object as freed. */ + metadata_update_state(meta, KFENCE_OBJECT_FREED); + + raw_spin_unlock_irqrestore(&meta->lock, flags); + + /* Protect to detect use-after-frees. */ + kfence_protect((unsigned long)addr); + + kcsan_end_scoped_access(&assert_page_exclusive); + if (!zombie) { + /* Add it to the tail of the freelist for reuse. */ + raw_spin_lock_irqsave(&kfence_freelist_lock, flags); + KFENCE_WARN_ON(!list_empty(&meta->list)); + list_add_tail(&meta->list, &kfence_freelist); + raw_spin_unlock_irqrestore(&kfence_freelist_lock, flags); + + atomic_long_dec(&counters[KFENCE_COUNTER_ALLOCATED]); + atomic_long_inc(&counters[KFENCE_COUNTER_FREES]); + } else { + /* See kfence_shutdown_cache(). */ + atomic_long_inc(&counters[KFENCE_COUNTER_ZOMBIES]); + } +} + +static void rcu_guarded_free(struct rcu_head *h) +{ + struct kfence_metadata *meta = container_of(h, struct kfence_metadata, rcu_head); + + kfence_guarded_free((void *)meta->addr, meta, false); +} + +static bool __init kfence_init_pool(void) +{ + unsigned long addr = (unsigned long)__kfence_pool; + struct page *pages; + int i; + + if (!__kfence_pool) + return false; + + if (!arch_kfence_init_pool()) + goto err; + + pages = virt_to_page(addr); + + /* + * Set up object pages: they must have PG_slab set, to avoid freeing + * these as real pages. + * + * We also want to avoid inserting kfence_free() in the kfree() + * fast-path in SLUB, and therefore need to ensure kfree() correctly + * enters __slab_free() slow-path. + */ + for (i = 0; i < KFENCE_POOL_SIZE / PAGE_SIZE; i++) { + if (!i || (i % 2)) + continue; + + /* Verify we do not have a compound head page. */ + if (WARN_ON(compound_head(&pages[i]) != &pages[i])) + goto err; + + __SetPageSlab(&pages[i]); + } + + /* + * Protect the first 2 pages. The first page is mostly unnecessary, and + * merely serves as an extended guard page. However, adding one + * additional page in the beginning gives us an even number of pages, + * which simplifies the mapping of address to metadata index. + */ + for (i = 0; i < 2; i++) { + if (unlikely(!kfence_protect(addr))) + goto err; + + addr += PAGE_SIZE; + } + + for (i = 0; i < CONFIG_KFENCE_NUM_OBJECTS; i++) { + struct kfence_metadata *meta = &kfence_metadata[i]; + + /* Initialize metadata. */ + INIT_LIST_HEAD(&meta->list); + raw_spin_lock_init(&meta->lock); + meta->state = KFENCE_OBJECT_UNUSED; + meta->addr = addr; /* Initialize for validation in metadata_to_pageaddr(). */ + list_add_tail(&meta->list, &kfence_freelist); + + /* Protect the right redzone. */ + if (unlikely(!kfence_protect(addr + PAGE_SIZE))) + goto err; + + addr += 2 * PAGE_SIZE; + } + + return true; + +err: + /* + * Only release unprotected pages, and do not try to go back and change + * page attributes due to risk of failing to do so as well. If changing + * page attributes for some pages fails, it is very likely that it also + * fails for the first page, and therefore expect addr==__kfence_pool in + * most failure cases. + */ + memblock_free_late(__pa(addr), KFENCE_POOL_SIZE - (addr - (unsigned long)__kfence_pool)); + __kfence_pool = NULL; + return false; +} + +/* === DebugFS Interface ==================================================== */ + +static int stats_show(struct seq_file *seq, void *v) +{ + int i; + + seq_printf(seq, "enabled: %i\n", READ_ONCE(kfence_enabled)); + for (i = 0; i < KFENCE_COUNTER_COUNT; i++) + seq_printf(seq, "%s: %ld\n", counter_names[i], atomic_long_read(&counters[i])); + + return 0; +} +DEFINE_SHOW_ATTRIBUTE(stats); + +/* + * debugfs seq_file operations for /sys/kernel/debug/kfence/objects. + * start_object() and next_object() return the object index + 1, because NULL is used + * to stop iteration. + */ +static void *start_object(struct seq_file *seq, loff_t *pos) +{ + if (*pos < CONFIG_KFENCE_NUM_OBJECTS) + return (void *)((long)*pos + 1); + return NULL; +} + +static void stop_object(struct seq_file *seq, void *v) +{ +} + +static void *next_object(struct seq_file *seq, void *v, loff_t *pos) +{ + ++*pos; + if (*pos < CONFIG_KFENCE_NUM_OBJECTS) + return (void *)((long)*pos + 1); + return NULL; +} + +static int show_object(struct seq_file *seq, void *v) +{ + struct kfence_metadata *meta = &kfence_metadata[(long)v - 1]; + unsigned long flags; + + raw_spin_lock_irqsave(&meta->lock, flags); + kfence_print_object(seq, meta); + raw_spin_unlock_irqrestore(&meta->lock, flags); + seq_puts(seq, "---------------------------------\n"); + + return 0; +} + +static const struct seq_operations object_seqops = { + .start = start_object, + .next = next_object, + .stop = stop_object, + .show = show_object, +}; + +static int open_objects(struct inode *inode, struct file *file) +{ + return seq_open(file, &object_seqops); +} + +static const struct file_operations objects_fops = { + .open = open_objects, + .read = seq_read, + .llseek = seq_lseek, +}; + +static int __init kfence_debugfs_init(void) +{ + struct dentry *kfence_dir = debugfs_create_dir("kfence", NULL); + + debugfs_create_file("stats", 0444, kfence_dir, NULL, &stats_fops); + debugfs_create_file("objects", 0400, kfence_dir, NULL, &objects_fops); + return 0; +} + +late_initcall(kfence_debugfs_init); + +/* === Allocation Gate Timer ================================================ */ + +/* + * Set up delayed work, which will enable and disable the static key. We need to + * use a work queue (rather than a simple timer), since enabling and disabling a + * static key cannot be done from an interrupt. + * + * Note: Toggling a static branch currently causes IPIs, and here we'll end up + * with a total of 2 IPIs to all CPUs. If this ends up a problem in future (with + * more aggressive sampling intervals), we could get away with a variant that + * avoids IPIs, at the cost of not immediately capturing allocations if the + * instructions remain cached. + */ +static struct delayed_work kfence_timer; +static void toggle_allocation_gate(struct work_struct *work) +{ + if (!READ_ONCE(kfence_enabled)) + return; + + /* Enable static key, and await allocation to happen. */ + atomic_set(&kfence_allocation_gate, 0); +#ifdef CONFIG_KFENCE_STATIC_KEYS + static_branch_enable(&kfence_allocation_key); + /* + * Await an allocation. Timeout after 1 second, in case the kernel stops + * doing allocations, to avoid stalling this worker task for too long. + */ + { + unsigned long end_wait = jiffies + HZ; + + do { + set_current_state(TASK_UNINTERRUPTIBLE); + if (atomic_read(&kfence_allocation_gate) != 0) + break; + schedule_timeout(1); + } while (time_before(jiffies, end_wait)); + __set_current_state(TASK_RUNNING); + } + /* Disable static key and reset timer. */ + static_branch_disable(&kfence_allocation_key); +#endif + schedule_delayed_work(&kfence_timer, msecs_to_jiffies(kfence_sample_interval)); +} +static DECLARE_DELAYED_WORK(kfence_timer, toggle_allocation_gate); + +/* === Public interface ===================================================== */ + +void __init kfence_alloc_pool(void) +{ + if (!kfence_sample_interval) + return; + + __kfence_pool = memblock_alloc(KFENCE_POOL_SIZE, PAGE_SIZE); + + if (!__kfence_pool) + pr_err("failed to allocate pool\n"); +} + +void __init kfence_init(void) +{ + /* Setting kfence_sample_interval to 0 on boot disables KFENCE. */ + if (!kfence_sample_interval) + return; + + if (!kfence_init_pool()) { + pr_err("%s failed\n", __func__); + return; + } + + WRITE_ONCE(kfence_enabled, true); + schedule_delayed_work(&kfence_timer, 0); + pr_info("initialized - using %lu bytes for %d objects", KFENCE_POOL_SIZE, + CONFIG_KFENCE_NUM_OBJECTS); + if (IS_ENABLED(CONFIG_DEBUG_KERNEL)) + pr_cont(" at 0x%px-0x%px\n", (void *)__kfence_pool, + (void *)(__kfence_pool + KFENCE_POOL_SIZE)); + else + pr_cont("\n"); +} + +void kfence_shutdown_cache(struct kmem_cache *s) +{ + unsigned long flags; + struct kfence_metadata *meta; + int i; + + for (i = 0; i < CONFIG_KFENCE_NUM_OBJECTS; i++) { + bool in_use; + + meta = &kfence_metadata[i]; + + /* + * If we observe some inconsistent cache and state pair where we + * should have returned false here, cache destruction is racing + * with either kmem_cache_alloc() or kmem_cache_free(). Taking + * the lock will not help, as different critical section + * serialization will have the same outcome. + */ + if (READ_ONCE(meta->cache) != s || + READ_ONCE(meta->state) != KFENCE_OBJECT_ALLOCATED) + continue; + + raw_spin_lock_irqsave(&meta->lock, flags); + in_use = meta->cache == s && meta->state == KFENCE_OBJECT_ALLOCATED; + raw_spin_unlock_irqrestore(&meta->lock, flags); + + if (in_use) { + /* + * This cache still has allocations, and we should not + * release them back into the freelist so they can still + * safely be used and retain the kernel's default + * behaviour of keeping the allocations alive (leak the + * cache); however, they effectively become "zombie + * allocations" as the KFENCE objects are the only ones + * still in use and the owning cache is being destroyed. + * + * We mark them freed, so that any subsequent use shows + * more useful error messages that will include stack + * traces of the user of the object, the original + * allocation, and caller to shutdown_cache(). + */ + kfence_guarded_free((void *)meta->addr, meta, /*zombie=*/true); + } + } + + for (i = 0; i < CONFIG_KFENCE_NUM_OBJECTS; i++) { + meta = &kfence_metadata[i]; + + /* See above. */ + if (READ_ONCE(meta->cache) != s || READ_ONCE(meta->state) != KFENCE_OBJECT_FREED) + continue; + + raw_spin_lock_irqsave(&meta->lock, flags); + if (meta->cache == s && meta->state == KFENCE_OBJECT_FREED) + meta->cache = NULL; + raw_spin_unlock_irqrestore(&meta->lock, flags); + } +} + +void *__kfence_alloc(struct kmem_cache *s, size_t size, gfp_t flags) +{ + /* + * allocation_gate only needs to become non-zero, so it doesn't make + * sense to continue writing to it and pay the associated contention + * cost, in case we have a large number of concurrent allocations. + */ + if (atomic_read(&kfence_allocation_gate) || atomic_inc_return(&kfence_allocation_gate) > 1) + return NULL; + + if (!READ_ONCE(kfence_enabled)) + return NULL; + + if (size > PAGE_SIZE) + return NULL; + + return kfence_guarded_alloc(s, size, flags); +} + +size_t kfence_ksize(const void *addr) +{ + const struct kfence_metadata *meta = addr_to_metadata((unsigned long)addr); + + /* + * Read locklessly -- if there is a race with __kfence_alloc(), this is + * either a use-after-free or invalid access. + */ + return meta ? meta->size : 0; +} + +void *kfence_object_start(const void *addr) +{ + const struct kfence_metadata *meta = addr_to_metadata((unsigned long)addr); + + /* + * Read locklessly -- if there is a race with __kfence_alloc(), this is + * either a use-after-free or invalid access. + */ + return meta ? (void *)meta->addr : NULL; +} + +void __kfence_free(void *addr) +{ + struct kfence_metadata *meta = addr_to_metadata((unsigned long)addr); + + /* + * If the objects of the cache are SLAB_TYPESAFE_BY_RCU, defer freeing + * the object, as the object page may be recycled for other-typed + * objects once it has been freed. meta->cache may be NULL if the cache + * was destroyed. + */ + if (unlikely(meta->cache && (meta->cache->flags & SLAB_TYPESAFE_BY_RCU))) + call_rcu(&meta->rcu_head, rcu_guarded_free); + else + kfence_guarded_free(addr, meta, false); +} + +bool kfence_handle_page_fault(unsigned long addr) +{ + const int page_index = (addr - (unsigned long)__kfence_pool) / PAGE_SIZE; + struct kfence_metadata *to_report = NULL; + enum kfence_error_type error_type; + unsigned long flags; + + if (!is_kfence_address((void *)addr)) + return false; + + if (!READ_ONCE(kfence_enabled)) /* If disabled at runtime ... */ + return kfence_unprotect(addr); /* ... unprotect and proceed. */ + + atomic_long_inc(&counters[KFENCE_COUNTER_BUGS]); + + if (page_index % 2) { + /* This is a redzone, report a buffer overflow. */ + struct kfence_metadata *meta; + int distance = 0; + + meta = addr_to_metadata(addr - PAGE_SIZE); + if (meta && READ_ONCE(meta->state) == KFENCE_OBJECT_ALLOCATED) { + to_report = meta; + /* Data race ok; distance calculation approximate. */ + distance = addr - data_race(meta->addr + meta->size); + } + + meta = addr_to_metadata(addr + PAGE_SIZE); + if (meta && READ_ONCE(meta->state) == KFENCE_OBJECT_ALLOCATED) { + /* Data race ok; distance calculation approximate. */ + if (!to_report || distance > data_race(meta->addr) - addr) + to_report = meta; + } + + if (!to_report) + goto out; + + raw_spin_lock_irqsave(&to_report->lock, flags); + to_report->unprotected_page = addr; + error_type = KFENCE_ERROR_OOB; + + /* + * If the object was freed before we took the look we can still + * report this as an OOB -- the report will simply show the + * stacktrace of the free as well. + */ + } else { + to_report = addr_to_metadata(addr); + if (!to_report) + goto out; + + raw_spin_lock_irqsave(&to_report->lock, flags); + error_type = KFENCE_ERROR_UAF; + /* + * We may race with __kfence_alloc(), and it is possible that a + * freed object may be reallocated. We simply report this as a + * use-after-free, with the stack trace showing the place where + * the object was re-allocated. + */ + } + +out: + if (to_report) { + kfence_report_error(addr, to_report, error_type); + raw_spin_unlock_irqrestore(&to_report->lock, flags); + } else { + /* This may be a UAF or OOB access, but we can't be sure. */ + kfence_report_error(addr, NULL, KFENCE_ERROR_INVALID); + } + + return kfence_unprotect(addr); /* Unprotect and let access proceed. */ +} diff --git a/mm/kfence/kfence.h b/mm/kfence/kfence.h new file mode 100644 index 000000000000..1014060f9707 --- /dev/null +++ b/mm/kfence/kfence.h @@ -0,0 +1,113 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Kernel Electric-Fence (KFENCE). For more info please see + * Documentation/dev-tools/kfence.rst. + * + * Copyright (C) 2020, Google LLC. + */ + +#ifndef MM_KFENCE_KFENCE_H +#define MM_KFENCE_KFENCE_H + +#include <linux/mm.h> +#include <linux/slab.h> +#include <linux/spinlock.h> +#include <linux/types.h> + +#include "../slab.h" /* for struct kmem_cache */ + +/* For non-debug builds, avoid leaking kernel pointers into dmesg. */ +#ifdef CONFIG_DEBUG_KERNEL +#define PTR_FMT "%px" +#else +#define PTR_FMT "%p" +#endif + +/* + * Get the canary byte pattern for @addr. Use a pattern that varies based on the + * lower 3 bits of the address, to detect memory corruptions with higher + * probability, where similar constants are used. + */ +#define KFENCE_CANARY_PATTERN(addr) ((u8)0xaa ^ (u8)((unsigned long)(addr) & 0x7)) + +/* Maximum stack depth for reports. */ +#define KFENCE_STACK_DEPTH 64 + +/* KFENCE object states. */ +enum kfence_object_state { + KFENCE_OBJECT_UNUSED, /* Object is unused. */ + KFENCE_OBJECT_ALLOCATED, /* Object is currently allocated. */ + KFENCE_OBJECT_FREED, /* Object was allocated, and then freed. */ +}; + +/* Alloc/free tracking information. */ +struct kfence_track { + pid_t pid; + int num_stack_entries; + unsigned long stack_entries[KFENCE_STACK_DEPTH]; +}; + +/* KFENCE metadata per guarded allocation. */ +struct kfence_metadata { + struct list_head list; /* Freelist node; access under kfence_freelist_lock. */ + struct rcu_head rcu_head; /* For delayed freeing. */ + + /* + * Lock protecting below data; to ensure consistency of the below data, + * since the following may execute concurrently: __kfence_alloc(), + * __kfence_free(), kfence_handle_page_fault(). However, note that we + * cannot grab the same metadata off the freelist twice, and multiple + * __kfence_alloc() cannot run concurrently on the same metadata. + */ + raw_spinlock_t lock; + + /* The current state of the object; see above. */ + enum kfence_object_state state; + + /* + * Allocated object address; cannot be calculated from size, because of + * alignment requirements. + * + * Invariant: ALIGN_DOWN(addr, PAGE_SIZE) is constant. + */ + unsigned long addr; + + /* + * The size of the original allocation. + */ + size_t size; + + /* + * The kmem_cache cache of the last allocation; NULL if never allocated + * or the cache has already been destroyed. + */ + struct kmem_cache *cache; + + /* + * In case of an invalid access, the page that was unprotected; we + * optimistically only store one address. + */ + unsigned long unprotected_page; + + /* Allocation and free stack information. */ + struct kfence_track alloc_track; + struct kfence_track free_track; +}; + +extern struct kfence_metadata kfence_metadata[CONFIG_KFENCE_NUM_OBJECTS]; + +/* KFENCE error types for report generation. */ +enum kfence_error_type { + KFENCE_ERROR_OOB, /* Detected a out-of-bounds access. */ + KFENCE_ERROR_UAF, /* Detected a use-after-free access. */ + KFENCE_ERROR_CORRUPTION, /* Detected a memory corruption on free. */ + KFENCE_ERROR_INVALID, /* Invalid access of unknown type. */ + KFENCE_ERROR_INVALID_FREE, /* Invalid free. */ +}; + +void kfence_report_error(unsigned long address, const struct kfence_metadata *meta, + enum kfence_error_type type); + +void kfence_print_object(struct seq_file *seq, const struct kfence_metadata *meta); + +#endif /* MM_KFENCE_KFENCE_H */ diff --git a/mm/kfence/report.c b/mm/kfence/report.c new file mode 100644 index 000000000000..64f27c8d46a3 --- /dev/null +++ b/mm/kfence/report.c @@ -0,0 +1,240 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KFENCE reporting. + * + * Copyright (C) 2020, Google LLC. + */ + +#include <stdarg.h> + +#include <linux/kernel.h> +#include <linux/lockdep.h> +#include <linux/printk.h> +#include <linux/seq_file.h> +#include <linux/stacktrace.h> +#include <linux/string.h> + +#include <asm/kfence.h> + +#include "kfence.h" + +/* Helper function to either print to a seq_file or to console. */ +__printf(2, 3) +static void seq_con_printf(struct seq_file *seq, const char *fmt, ...) +{ + va_list args; + + va_start(args, fmt); + if (seq) + seq_vprintf(seq, fmt, args); + else + vprintk(fmt, args); + va_end(args); +} + +/* + * Get the number of stack entries to skip to get out of MM internals. @type is + * optional, and if set to NULL, assumes an allocation or free stack. + */ +static int get_stack_skipnr(const unsigned long stack_entries[], int num_entries, + const enum kfence_error_type *type) +{ + char buf[64]; + int skipnr, fallback = 0; + bool is_access_fault = false; + + if (type) { + /* Depending on error type, find different stack entries. */ + switch (*type) { + case KFENCE_ERROR_UAF: + case KFENCE_ERROR_OOB: + case KFENCE_ERROR_INVALID: + is_access_fault = true; + break; + case KFENCE_ERROR_CORRUPTION: + case KFENCE_ERROR_INVALID_FREE: + break; + } + } + + for (skipnr = 0; skipnr < num_entries; skipnr++) { + int len = scnprintf(buf, sizeof(buf), "%ps", (void *)stack_entries[skipnr]); + + if (is_access_fault) { + if (!strncmp(buf, KFENCE_SKIP_ARCH_FAULT_HANDLER, len)) + goto found; + } else { + if (str_has_prefix(buf, "kfence_") || str_has_prefix(buf, "__kfence_") || + !strncmp(buf, "__slab_free", len)) { + /* + * In case of tail calls from any of the below + * to any of the above. + */ + fallback = skipnr + 1; + } + + /* Also the *_bulk() variants by only checking prefixes. */ + if (str_has_prefix(buf, "kfree") || + str_has_prefix(buf, "kmem_cache_free") || + str_has_prefix(buf, "__kmalloc") || + str_has_prefix(buf, "kmem_cache_alloc")) + goto found; + } + } + if (fallback < num_entries) + return fallback; +found: + skipnr++; + return skipnr < num_entries ? skipnr : 0; +} + +static void kfence_print_stack(struct seq_file *seq, const struct kfence_metadata *meta, + bool show_alloc) +{ + const struct kfence_track *track = show_alloc ? &meta->alloc_track : &meta->free_track; + + if (track->num_stack_entries) { + /* Skip allocation/free internals stack. */ + int i = get_stack_skipnr(track->stack_entries, track->num_stack_entries, NULL); + + /* stack_trace_seq_print() does not exist; open code our own. */ + for (; i < track->num_stack_entries; i++) + seq_con_printf(seq, " %pS\n", (void *)track->stack_entries[i]); + } else { + seq_con_printf(seq, " no %s stack\n", show_alloc ? "allocation" : "deallocation"); + } +} + +void kfence_print_object(struct seq_file *seq, const struct kfence_metadata *meta) +{ + const int size = abs(meta->size); + const unsigned long start = meta->addr; + const struct kmem_cache *const cache = meta->cache; + + lockdep_assert_held(&meta->lock); + + if (meta->state == KFENCE_OBJECT_UNUSED) { + seq_con_printf(seq, "kfence-#%zd unused\n", meta - kfence_metadata); + return; + } + + seq_con_printf(seq, + "kfence-#%zd [0x" PTR_FMT "-0x" PTR_FMT + ", size=%d, cache=%s] allocated by task %d:\n", + meta - kfence_metadata, (void *)start, (void *)(start + size - 1), size, + (cache && cache->name) ? cache->name : "<destroyed>", meta->alloc_track.pid); + kfence_print_stack(seq, meta, true); + + if (meta->state == KFENCE_OBJECT_FREED) { + seq_con_printf(seq, "\nfreed by task %d:\n", meta->free_track.pid); + kfence_print_stack(seq, meta, false); + } +} + +/* + * Show bytes at @addr that are different from the expected canary values, up to + * @max_bytes. + */ +static void print_diff_canary(unsigned long address, size_t bytes_to_show, + const struct kfence_metadata *meta) +{ + const unsigned long show_until_addr = address + bytes_to_show; + const u8 *cur, *end; + + /* Do not show contents of object nor read into following guard page. */ + end = (const u8 *)(address < meta->addr ? min(show_until_addr, meta->addr) + : min(show_until_addr, PAGE_ALIGN(address))); + + pr_cont("["); + for (cur = (const u8 *)address; cur < end; cur++) { + if (*cur == KFENCE_CANARY_PATTERN(cur)) + pr_cont(" ."); + else if (IS_ENABLED(CONFIG_DEBUG_KERNEL)) + pr_cont(" 0x%02x", *cur); + else /* Do not leak kernel memory in non-debug builds. */ + pr_cont(" !"); + } + pr_cont(" ]"); +} + +void kfence_report_error(unsigned long address, const struct kfence_metadata *meta, + enum kfence_error_type type) +{ + unsigned long stack_entries[KFENCE_STACK_DEPTH] = { 0 }; + int num_stack_entries = stack_trace_save(stack_entries, KFENCE_STACK_DEPTH, 1); + int skipnr = get_stack_skipnr(stack_entries, num_stack_entries, &type); + const ptrdiff_t object_index = meta ? meta - kfence_metadata : -1; + + /* Require non-NULL meta, except if KFENCE_ERROR_INVALID. */ + if (WARN_ON(type != KFENCE_ERROR_INVALID && !meta)) + return; + + if (meta) + lockdep_assert_held(&meta->lock); + /* + * Because we may generate reports in printk-unfriendly parts of the + * kernel, such as scheduler code, the use of printk() could deadlock. + * Until such time that all printing code here is safe in all parts of + * the kernel, accept the risk, and just get our message out (given the + * system might already behave unpredictably due to the memory error). + * As such, also disable lockdep to hide warnings, and avoid disabling + * lockdep for the rest of the kernel. + */ + lockdep_off(); + + pr_err("==================================================================\n"); + /* Print report header. */ + switch (type) { + case KFENCE_ERROR_OOB: { + const bool left_of_object = address < meta->addr; + + pr_err("BUG: KFENCE: out-of-bounds in %pS\n\n", (void *)stack_entries[skipnr]); + pr_err("Out-of-bounds access at 0x" PTR_FMT " (%luB %s of kfence-#%zd):\n", + (void *)address, + left_of_object ? meta->addr - address : address - meta->addr, + left_of_object ? "left" : "right", object_index); + break; + } + case KFENCE_ERROR_UAF: + pr_err("BUG: KFENCE: use-after-free in %pS\n\n", (void *)stack_entries[skipnr]); + pr_err("Use-after-free access at 0x" PTR_FMT " (in kfence-#%zd):\n", + (void *)address, object_index); + break; + case KFENCE_ERROR_CORRUPTION: + pr_err("BUG: KFENCE: memory corruption in %pS\n\n", (void *)stack_entries[skipnr]); + pr_err("Corrupted memory at 0x" PTR_FMT " ", (void *)address); + print_diff_canary(address, 16, meta); + pr_cont(" (in kfence-#%zd):\n", object_index); + break; + case KFENCE_ERROR_INVALID: + pr_err("BUG: KFENCE: invalid access in %pS\n\n", (void *)stack_entries[skipnr]); + pr_err("Invalid access at 0x" PTR_FMT ":\n", (void *)address); + break; + case KFENCE_ERROR_INVALID_FREE: + pr_err("BUG: KFENCE: invalid free in %pS\n\n", (void *)stack_entries[skipnr]); + pr_err("Invalid free of 0x" PTR_FMT " (in kfence-#%zd):\n", (void *)address, + object_index); + break; + } + + /* Print stack trace and object info. */ + stack_trace_print(stack_entries + skipnr, num_stack_entries - skipnr, 0); + + if (meta) { + pr_err("\n"); + kfence_print_object(NULL, meta); + } + + /* Print report footer. */ + pr_err("\n"); + dump_stack_print_info(KERN_ERR); + pr_err("==================================================================\n"); + + lockdep_on(); + + if (panic_on_warn) + panic("panic_on_warn set ...\n"); + + /* We encountered a memory unsafety error, taint the kernel! */ + add_taint(TAINT_BAD_PAGE, LOCKDEP_STILL_OK); +} -- 2.25.1

1 0

[PATCH 0/9]
by 1415317271＠qq.com 18 Aug '21

18 Aug '21

From: shang <1415317271(a)qq.com> Transplantation of KFENCE KFENCE could detect many types of memory safety errors. The test cases successfully output the log when booting the kernel after enabling the KFENCE and KFENCE integration test suite at the openEuler OLK 5.10 kernel compile. Yingjie Shang: Transplant KFENCE from Linux kernel v5.13 to openEuler kernel OLK 5.10. Bixuan Cui: Reviewd the transplant patches. Alexander Potapenko (5): mm: add Kernel Electric-Fence infrastructure x86, kfence: enable KFENCE for x86 mm, kfence: insert KFENCE hooks for SLAB mm, kfence: insert KFENCE hooks for SLUB kfence, kasan: make KFENCE compatible with KASAN Marco Elver (4): arm64, kfence: enable KFENCE for ARM64 kfence: use pt_regs to generate stack trace on faults kfence, Documentation: add KFENCE documentation kfence: add test suite Documentation/dev-tools/index.rst | 1 + Documentation/dev-tools/kfence.rst | 298 ++++++++++ arch/arm64/Kconfig | 1 + arch/arm64/include/asm/kfence.h | 22 + arch/arm64/mm/fault.c | 4 + arch/arm64/mm/mmu.c | 7 +- arch/x86/Kconfig | 1 + arch/x86/include/asm/kfence.h | 64 +++ arch/x86/mm/fault.c | 5 + include/linux/kfence.h | 222 ++++++++ include/linux/slab_def.h | 3 + include/linux/slub_def.h | 3 + init/main.c | 3 + lib/Kconfig.debug | 1 + lib/Kconfig.kfence | 82 +++ mm/Makefile | 1 + mm/kasan/common.c | 6 + mm/kasan/generic.c | 3 +- mm/kfence/Makefile | 6 + mm/kfence/core.c | 845 ++++++++++++++++++++++++++++ mm/kfence/kfence.h | 113 ++++ mm/kfence/kfence_test.c | 858 +++++++++++++++++++++++++++++ mm/kfence/report.c | 258 +++++++++ mm/slab.c | 38 +- mm/slab_common.c | 5 +- mm/slub.c | 61 +- 26 files changed, 2884 insertions(+), 27 deletions(-) create mode 100644 Documentation/dev-tools/kfence.rst create mode 100644 arch/arm64/include/asm/kfence.h create mode 100644 arch/x86/include/asm/kfence.h create mode 100644 include/linux/kfence.h create mode 100644 lib/Kconfig.kfence create mode 100644 mm/kfence/Makefile create mode 100644 mm/kfence/core.c create mode 100644 mm/kfence/kfence.h create mode 100644 mm/kfence/kfence_test.c create mode 100644 mm/kfence/report.c -- 2.25.1

1 0

回复：[PATCH kernel-4.19 0/4] Introduce default passthrough mode for some SoCs
by guohui＠uniontech.com 17 Aug '21

17 Aug '21

1 0

【Meeting Notice】openEuler kernel 技术分享第十期 & 双周例会 Time: 2021-08-20 14:00-17:00
by Meeting Book 17 Aug '21

17 Aug '21

1 0

[PATCH kernel-4.19 1/2] hso: fix bailout in error case of probe
by Yang Yingliang 17 Aug '21

17 Aug '21

From: Oliver Neukum <oneukum(a)suse.com> mainline inclusion from mainline-v5.9-rc1 commit 5fcfb6d0bfcda17f0d0656e4e5b3710af2bbaae5 category: bugfix bugzilla: NA CVE: CVE-2021-37159 --------------------------- The driver tries to reuse code for disconnect in case of a failed probe. If resources need to be freed after an error in probe, the netdev must not be freed because it has never been registered. Fix it by telling the helper which path we are in. Signed-off-by: Oliver Neukum <oneukum(a)suse.com> Signed-off-by: David S. Miller <davem(a)davemloft.net> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> Reviewed-by: Yue Haibing <yuehaibing(a)huawei.com> Reviewed-by: Xiu Jianfeng <xiujianfeng(a)huawei.com> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> --- drivers/net/usb/hso.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/net/usb/hso.c b/drivers/net/usb/hso.c index a66077f514572..0839da773e62b 100644 --- a/drivers/net/usb/hso.c +++ b/drivers/net/usb/hso.c @@ -2368,7 +2368,7 @@ static int remove_net_device(struct hso_device *hso_dev) } /* Frees our network device */ -static void hso_free_net_device(struct hso_device *hso_dev) +static void hso_free_net_device(struct hso_device *hso_dev, bool bailout) { int i; struct hso_net *hso_net = dev2net(hso_dev); @@ -2391,7 +2391,7 @@ static void hso_free_net_device(struct hso_device *hso_dev) kfree(hso_net->mux_bulk_tx_buf); hso_net->mux_bulk_tx_buf = NULL; - if (hso_net->net) + if (hso_net->net && !bailout) free_netdev(hso_net->net); kfree(hso_dev); @@ -2567,7 +2567,7 @@ static struct hso_device *hso_create_net_device(struct usb_interface *interface, return hso_dev; exit: - hso_free_net_device(hso_dev); + hso_free_net_device(hso_dev, true); return NULL; } @@ -3132,7 +3132,7 @@ static void hso_free_interface(struct usb_interface *interface) rfkill_unregister(rfk); rfkill_destroy(rfk); } - hso_free_net_device(network_table[i]); + hso_free_net_device(network_table[i], false); } } } -- 2.25.1

1 1

请教IMA完整性度量问题
by Zhoumingxing 17 Aug '21

17 Aug '21

看了天行老师介绍openEuler 内核完整性度量的视频之后，主要有几个问题想请教 1.我们在开启了操作系统的IMA度量之后，系统中例如vim查看一个文件，那么就会相应在度量日志中增加度量记录，这种情况是因为默认的IMA度量策略的特点吗？如果我想更改系统的IMA度量策略，请问应该怎么操作呢？比如我想只度量某个可执行文件，能不能修改策略指定只度量该可执行文件的路径，这样开启IMA度量之后，度量日志里面就只有两条记录，度量日志文件也不因为我vim文件而变化。 2.老师在视频中讲到在OpenEuler上部署IMA时，添加grub启动参数详细的可以查看文档，具体指的是哪个参考文档呢？麻烦老师抽空看一下，超级感谢！

1 0

[PATCH kernel-4.19 0/8] backport linux-4.19.204
by Yang Yingliang 17 Aug '21

17 Aug '21

Daniel Borkmann (1): bpf, selftests: Adjust few selftest outcomes wrt unreachable code Greg Kroah-Hartman (1): Linux 4.19.204 Lai Jiangshan (1): KVM: X86: MMU: Use the correct inherited permissions to get shadow page Masami Hiramatsu (1): tracing: Reject string operand in the histogram expression Miklos Szeredi (1): ovl: prevent private clone if bind mount is not allowed Pali Rohár (1): ppp: Fix generating ppp unit id when ifname is not specified Sean Christopherson (1): KVM: SVM: Fix off-by-one indexing when nullifying last used SEV VMCB YueHaibing (1): net: xilinx_emaclite: Do not print real IOMEM pointer Documentation/virtual/kvm/mmu.txt | 4 +- Makefile | 2 +- arch/x86/kvm/paging_tmpl.h | 14 ++++--- arch/x86/kvm/svm.c | 2 +- drivers/net/ethernet/xilinx/xilinx_emaclite.c | 5 +-- drivers/net/ppp/ppp_generic.c | 19 +++++++-- fs/namespace.c | 42 ++++++++++++------- kernel/trace/trace_events_hist.c | 14 +++++++ tools/testing/selftests/bpf/test_verifier.c | 2 + 9 files changed, 74 insertions(+), 30 deletions(-) -- 2.25.1

1 8

[PATCH kernel-4.19 01/54] Revert "ACPICA: Fix memory leak caused by _CID repair function"
by Yang Yingliang 16 Aug '21

16 Aug '21

From: "Rafael J. Wysocki" <rafael.j.wysocki(a)intel.com> stable inclusion from linux-4.19.203 commit 87db7214e292d6b53e2068311c090acad47ad272 -------------------------------- commit 6511a8b5b7a65037340cd8ee91a377811effbc83 upstream. Revert commit c27bac0314131 ("ACPICA: Fix memory leak caused by _CID repair function") which is reported to cause a boot issue on Acer Swift 3 (SF314-51). Reported-by: Adrien Precigout <dev(a)asdrip.fr> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki(a)intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> --- drivers/acpi/acpica/nsrepair2.c | 7 ------- 1 file changed, 7 deletions(-) diff --git a/drivers/acpi/acpica/nsrepair2.c b/drivers/acpi/acpica/nsrepair2.c index 4c8ce483805d8..a3bd6280882c3 100644 --- a/drivers/acpi/acpica/nsrepair2.c +++ b/drivers/acpi/acpica/nsrepair2.c @@ -375,13 +375,6 @@ acpi_ns_repair_CID(struct acpi_evaluate_info *info, (*element_ptr)->common.reference_count = original_ref_count; - - /* - * The original_element holds a reference from the package object - * that represents _HID. Since a new element was created by _HID, - * remove the reference from the _CID package. - */ - acpi_ut_remove_reference(original_element); } element_ptr++; -- 2.25.1

1 53

[PATCH openEuler-1.0-LTS 1/4] scsi: iscsi: Fix conn use after free during resets
by Yang Yingliang 16 Aug '21

16 Aug '21

From: Mike Christie <michael.christie(a)oracle.com> stable inclusion from linux-4.19.198 commit bf20d85a88384574fabb3d53ad62a8af57e7ab11 -------------------------------- If we haven't done a unbind target call we can race where iscsi_conn_teardown wakes up the EH thread and then frees the conn while those threads are still accessing the conn ehwait. We can only do one TMF per session so this just moves the TMF fields from the conn to the session. We can then rely on the iscsi_session_teardown->iscsi_remove_session->__iscsi_unbind_session call to remove the target and it's devices, and know after that point there is no device or scsi-ml callout trying to access the session. Link: https://lore.kernel.org/r/20210525181821.7617-14-michael.christie@oracle.com Reviewed-by: Lee Duncan <lduncan(a)suse.com> Signed-off-by: Mike Christie <michael.christie(a)oracle.com> Signed-off-by: Martin K. Petersen <martin.petersen(a)oracle.com> conflcits: drivers/scsi/libiscsi.c Signed-off-by: Ye Bin <yebin10(a)huawei.com> Reviewed-by: Jason Yan <yanaijie(a)huawei.com> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> --- drivers/scsi/libiscsi.c | 116 +++++++++++++++++++--------------------- include/scsi/libiscsi.h | 11 ++-- 2 files changed, 61 insertions(+), 66 deletions(-) diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c index 8ea441fe8aba3..75096f1565425 100644 --- a/drivers/scsi/libiscsi.c +++ b/drivers/scsi/libiscsi.c @@ -265,11 +265,11 @@ static int iscsi_prep_bidi_ahs(struct iscsi_task *task) */ static int iscsi_check_tmf_restrictions(struct iscsi_task *task, int opcode) { - struct iscsi_conn *conn = task->conn; - struct iscsi_tm *tmf = &conn->tmhdr; + struct iscsi_session *session = task->conn->session; + struct iscsi_tm *tmf = &session->tmhdr; u64 hdr_lun; - if (conn->tmf_state == TMF_INITIAL) + if (session->tmf_state == TMF_INITIAL) return 0; if ((tmf->opcode & ISCSI_OPCODE_MASK) != ISCSI_OP_SCSI_TMFUNC) @@ -289,24 +289,19 @@ static int iscsi_check_tmf_restrictions(struct iscsi_task *task, int opcode) * Fail all SCSI cmd PDUs */ if (opcode != ISCSI_OP_SCSI_DATA_OUT) { - iscsi_conn_printk(KERN_INFO, conn, - "task [op %x itt " - "0x%x/0x%x] " - "rejected.\n", - opcode, task->itt, - task->hdr_itt); + iscsi_session_printk(KERN_INFO, session, + "task [op %x itt 0x%x/0x%x] rejected.\n", + opcode, task->itt, task->hdr_itt); return -EACCES; } /* * And also all data-out PDUs in response to R2T * if fast_abort is set. */ - if (conn->session->fast_abort) { - iscsi_conn_printk(KERN_INFO, conn, - "task [op %x itt " - "0x%x/0x%x] fast abort.\n", - opcode, task->itt, - task->hdr_itt); + if (session->fast_abort) { + iscsi_session_printk(KERN_INFO, session, + "task [op %x itt 0x%x/0x%x] fast abort.\n", + opcode, task->itt, task->hdr_itt); return -EACCES; } break; @@ -319,7 +314,7 @@ static int iscsi_check_tmf_restrictions(struct iscsi_task *task, int opcode) */ if (opcode == ISCSI_OP_SCSI_DATA_OUT && task->hdr_itt == tmf->rtt) { - ISCSI_DBG_SESSION(conn->session, + ISCSI_DBG_SESSION(session, "Preventing task %x/%x from sending " "data-out due to abort task in " "progress\n", task->itt, @@ -993,20 +988,21 @@ iscsi_data_in_rsp(struct iscsi_conn *conn, struct iscsi_hdr *hdr, static void iscsi_tmf_rsp(struct iscsi_conn *conn, struct iscsi_hdr *hdr) { struct iscsi_tm_rsp *tmf = (struct iscsi_tm_rsp *)hdr; + struct iscsi_session *session = conn->session; conn->exp_statsn = be32_to_cpu(hdr->statsn) + 1; conn->tmfrsp_pdus_cnt++; - if (conn->tmf_state != TMF_QUEUED) + if (session->tmf_state != TMF_QUEUED) return; if (tmf->response == ISCSI_TMF_RSP_COMPLETE) - conn->tmf_state = TMF_SUCCESS; + session->tmf_state = TMF_SUCCESS; else if (tmf->response == ISCSI_TMF_RSP_NO_TASK) - conn->tmf_state = TMF_NOT_FOUND; + session->tmf_state = TMF_NOT_FOUND; else - conn->tmf_state = TMF_FAILED; - wake_up(&conn->ehwait); + session->tmf_state = TMF_FAILED; + wake_up(&session->ehwait); } static int iscsi_send_nopout(struct iscsi_conn *conn, struct iscsi_nopin *rhdr) @@ -1879,15 +1875,14 @@ EXPORT_SYMBOL_GPL(iscsi_target_alloc); static void iscsi_tmf_timedout(struct timer_list *t) { - struct iscsi_conn *conn = from_timer(conn, t, tmf_timer); - struct iscsi_session *session = conn->session; + struct iscsi_session *session = from_timer(session, t, tmf_timer); spin_lock(&session->frwd_lock); - if (conn->tmf_state == TMF_QUEUED) { - conn->tmf_state = TMF_TIMEDOUT; + if (session->tmf_state == TMF_QUEUED) { + session->tmf_state = TMF_TIMEDOUT; ISCSI_DBG_EH(session, "tmf timedout\n"); /* unblock eh_abort() */ - wake_up(&conn->ehwait); + wake_up(&session->ehwait); } spin_unlock(&session->frwd_lock); } @@ -1910,8 +1905,8 @@ static int iscsi_exec_task_mgmt_fn(struct iscsi_conn *conn, return -EPERM; } conn->tmfcmd_pdus_cnt++; - conn->tmf_timer.expires = timeout * HZ + jiffies; - add_timer(&conn->tmf_timer); + session->tmf_timer.expires = timeout * HZ + jiffies; + add_timer(&session->tmf_timer); ISCSI_DBG_EH(session, "tmf set timeout\n"); spin_unlock_bh(&session->frwd_lock); @@ -1925,12 +1920,12 @@ static int iscsi_exec_task_mgmt_fn(struct iscsi_conn *conn, * 3) session is terminated or restarted or userspace has * given up on recovery */ - wait_event_interruptible(conn->ehwait, age != session->age || + wait_event_interruptible(session->ehwait, age != session->age || session->state != ISCSI_STATE_LOGGED_IN || - conn->tmf_state != TMF_QUEUED); + session->tmf_state != TMF_QUEUED); if (signal_pending(current)) flush_signals(current); - del_timer_sync(&conn->tmf_timer); + del_timer_sync(&session->tmf_timer); mutex_lock(&session->eh_mutex); spin_lock_bh(&session->frwd_lock); @@ -2320,17 +2315,17 @@ int iscsi_eh_abort(struct scsi_cmnd *sc) } /* only have one tmf outstanding at a time */ - if (conn->tmf_state != TMF_INITIAL) + if (session->tmf_state != TMF_INITIAL) goto failed; - conn->tmf_state = TMF_QUEUED; + session->tmf_state = TMF_QUEUED; - hdr = &conn->tmhdr; + hdr = &session->tmhdr; iscsi_prep_abort_task_pdu(task, hdr); if (iscsi_exec_task_mgmt_fn(conn, hdr, age, session->abort_timeout)) goto failed; - switch (conn->tmf_state) { + switch (session->tmf_state) { case TMF_SUCCESS: spin_unlock_bh(&session->frwd_lock); /* @@ -2345,7 +2340,7 @@ int iscsi_eh_abort(struct scsi_cmnd *sc) */ spin_lock_bh(&session->frwd_lock); fail_scsi_task(task, DID_ABORT); - conn->tmf_state = TMF_INITIAL; + session->tmf_state = TMF_INITIAL; memset(hdr, 0, sizeof(*hdr)); spin_unlock_bh(&session->frwd_lock); iscsi_start_tx(conn); @@ -2356,7 +2351,7 @@ int iscsi_eh_abort(struct scsi_cmnd *sc) goto failed_unlocked; case TMF_NOT_FOUND: if (!sc->SCp.ptr) { - conn->tmf_state = TMF_INITIAL; + session->tmf_state = TMF_INITIAL; memset(hdr, 0, sizeof(*hdr)); /* task completed before tmf abort response */ ISCSI_DBG_EH(session, "sc completed while abort in " @@ -2365,7 +2360,7 @@ int iscsi_eh_abort(struct scsi_cmnd *sc) } /* fall through */ default: - conn->tmf_state = TMF_INITIAL; + session->tmf_state = TMF_INITIAL; goto failed; } @@ -2424,11 +2419,11 @@ int iscsi_eh_device_reset(struct scsi_cmnd *sc) conn = session->leadconn; /* only have one tmf outstanding at a time */ - if (conn->tmf_state != TMF_INITIAL) + if (session->tmf_state != TMF_INITIAL) goto unlock; - conn->tmf_state = TMF_QUEUED; + session->tmf_state = TMF_QUEUED; - hdr = &conn->tmhdr; + hdr = &session->tmhdr; iscsi_prep_lun_reset_pdu(sc, hdr); if (iscsi_exec_task_mgmt_fn(conn, hdr, session->age, @@ -2437,7 +2432,7 @@ int iscsi_eh_device_reset(struct scsi_cmnd *sc) goto unlock; } - switch (conn->tmf_state) { + switch (session->tmf_state) { case TMF_SUCCESS: break; case TMF_TIMEDOUT: @@ -2445,7 +2440,7 @@ int iscsi_eh_device_reset(struct scsi_cmnd *sc) iscsi_conn_failure(conn, ISCSI_ERR_SCSI_EH_SESSION_RST); goto done; default: - conn->tmf_state = TMF_INITIAL; + session->tmf_state = TMF_INITIAL; goto unlock; } @@ -2457,7 +2452,7 @@ int iscsi_eh_device_reset(struct scsi_cmnd *sc) spin_lock_bh(&session->frwd_lock); memset(hdr, 0, sizeof(*hdr)); fail_scsi_tasks(conn, sc->device->lun, DID_ERROR); - conn->tmf_state = TMF_INITIAL; + session->tmf_state = TMF_INITIAL; spin_unlock_bh(&session->frwd_lock); iscsi_start_tx(conn); @@ -2480,8 +2475,7 @@ void iscsi_session_recovery_timedout(struct iscsi_cls_session *cls_session) spin_lock_bh(&session->frwd_lock); if (session->state != ISCSI_STATE_LOGGED_IN) { session->state = ISCSI_STATE_RECOVERY_FAILED; - if (session->leadconn) - wake_up(&session->leadconn->ehwait); + wake_up(&session->ehwait); } spin_unlock_bh(&session->frwd_lock); } @@ -2536,7 +2530,7 @@ int iscsi_eh_session_reset(struct scsi_cmnd *sc) iscsi_conn_failure(conn, ISCSI_ERR_SCSI_EH_SESSION_RST); ISCSI_DBG_EH(session, "wait for relogin\n"); - wait_event_interruptible_timeout(conn->ehwait, + wait_event_interruptible_timeout(session->ehwait, session->state == ISCSI_STATE_TERMINATE || session->state == ISCSI_STATE_LOGGED_IN || session->state == ISCSI_STATE_RECOVERY_FAILED, @@ -2598,11 +2592,11 @@ static int iscsi_eh_target_reset(struct scsi_cmnd *sc) conn = session->leadconn; /* only have one tmf outstanding at a time */ - if (conn->tmf_state != TMF_INITIAL) + if (session->tmf_state != TMF_INITIAL) goto unlock; - conn->tmf_state = TMF_QUEUED; + session->tmf_state = TMF_QUEUED; - hdr = &conn->tmhdr; + hdr = &session->tmhdr; iscsi_prep_tgt_reset_pdu(sc, hdr); if (iscsi_exec_task_mgmt_fn(conn, hdr, session->age, @@ -2611,7 +2605,7 @@ static int iscsi_eh_target_reset(struct scsi_cmnd *sc) goto unlock; } - switch (conn->tmf_state) { + switch (session->tmf_state) { case TMF_SUCCESS: break; case TMF_TIMEDOUT: @@ -2619,7 +2613,7 @@ static int iscsi_eh_target_reset(struct scsi_cmnd *sc) iscsi_conn_failure(conn, ISCSI_ERR_SCSI_EH_SESSION_RST); goto done; default: - conn->tmf_state = TMF_INITIAL; + session->tmf_state = TMF_INITIAL; goto unlock; } @@ -2631,7 +2625,7 @@ static int iscsi_eh_target_reset(struct scsi_cmnd *sc) spin_lock_bh(&session->frwd_lock); memset(hdr, 0, sizeof(*hdr)); fail_scsi_tasks(conn, -1, DID_ERROR); - conn->tmf_state = TMF_INITIAL; + session->tmf_state = TMF_INITIAL; spin_unlock_bh(&session->frwd_lock); iscsi_start_tx(conn); @@ -2961,7 +2955,10 @@ iscsi_session_setup(struct iscsi_transport *iscsit, struct Scsi_Host *shost, session->tt = iscsit; session->dd_data = cls_session->dd_data + sizeof(*session); + session->tmf_state = TMF_INITIAL; + timer_setup(&session->tmf_timer, iscsi_tmf_timedout, 0); mutex_init(&session->eh_mutex); + spin_lock_init(&session->frwd_lock); spin_lock_init(&session->back_lock); @@ -3065,7 +3062,7 @@ iscsi_conn_setup(struct iscsi_cls_session *cls_session, int dd_size, conn->c_stage = ISCSI_CONN_INITIAL_STAGE; conn->id = conn_idx; conn->exp_statsn = 0; - conn->tmf_state = TMF_INITIAL; + session->tmf_state = TMF_INITIAL; conn->intimate_cpu = -1; timer_setup(&conn->transport_timer, iscsi_check_transport_timeouts, 0); @@ -3091,8 +3088,7 @@ iscsi_conn_setup(struct iscsi_cls_session *cls_session, int dd_size, goto login_task_data_alloc_fail; conn->login_task->data = conn->data = data; - timer_setup(&conn->tmf_timer, iscsi_tmf_timedout, 0); - init_waitqueue_head(&conn->ehwait); + init_waitqueue_head(&session->ehwait); return cls_conn; @@ -3127,7 +3123,7 @@ void iscsi_conn_teardown(struct iscsi_cls_conn *cls_conn) * leading connection? then give up on recovery. */ session->state = ISCSI_STATE_TERMINATE; - wake_up(&conn->ehwait); + wake_up(&session->ehwait); } spin_unlock_bh(&session->frwd_lock); @@ -3202,7 +3198,7 @@ int iscsi_conn_start(struct iscsi_cls_conn *cls_conn) * commands after successful recovery */ conn->stop_stage = 0; - conn->tmf_state = TMF_INITIAL; + session->tmf_state = TMF_INITIAL; session->age++; if (session->age == 16) session->age = 0; @@ -3216,7 +3212,7 @@ int iscsi_conn_start(struct iscsi_cls_conn *cls_conn) spin_unlock_bh(&session->frwd_lock); iscsi_unblock_session(session->cls_session); - wake_up(&conn->ehwait); + wake_up(&session->ehwait); return 0; } EXPORT_SYMBOL_GPL(iscsi_conn_start); @@ -3309,7 +3305,7 @@ static void iscsi_start_session_recovery(struct iscsi_session *session, spin_lock_bh(&session->frwd_lock); fail_scsi_tasks(conn, -1, DID_TRANSPORT_DISRUPTED); fail_mgmt_tasks(session, conn); - memset(&conn->tmhdr, 0, sizeof(conn->tmhdr)); + memset(&session->tmhdr, 0, sizeof(session->tmhdr)); spin_unlock_bh(&session->frwd_lock); mutex_unlock(&session->eh_mutex); } diff --git a/include/scsi/libiscsi.h b/include/scsi/libiscsi.h index c14d739c88873..156232a9e48b2 100644 --- a/include/scsi/libiscsi.h +++ b/include/scsi/libiscsi.h @@ -208,12 +208,6 @@ struct iscsi_conn { unsigned long suspend_tx; /* suspend Tx */ unsigned long suspend_rx; /* suspend Rx */ - /* abort */ - wait_queue_head_t ehwait; /* used in eh_abort() */ - struct iscsi_tm tmhdr; - struct timer_list tmf_timer; - int tmf_state; /* see TMF_INITIAL, etc.*/ - /* negotiated params */ unsigned max_recv_dlength; /* initiator_max_recv_dsl*/ unsigned max_xmit_dlength; /* target_max_recv_dsl */ @@ -284,6 +278,11 @@ struct iscsi_session { * and recv lock. */ struct mutex eh_mutex; + /* abort */ + wait_queue_head_t ehwait; /* used in eh_abort() */ + struct iscsi_tm tmhdr; + struct timer_list tmf_timer; + int tmf_state; /* see TMF_INITIAL, etc.*/ /* iSCSI session-wide sequencing */ uint32_t cmdsn; -- 2.25.1

1 3

[PATCH openEuler-21.09] once: Fix panic when module unload
by Zheng Zengkai 16 Aug '21

16 Aug '21

From: Kefeng Wang <wangkefeng.wang(a)huawei.com> mainline inclusion from mainline-5.14-rc6 commit 1027b96ec9d34f9abab69bc1a4dc5b1ad8ab1349 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I45V8P CVE: NA ------------------------------------------------- DO_ONCE DEFINE_STATIC_KEY_TRUE(___once_key); __do_once_done once_disable_jump(once_key); INIT_WORK(&w->work, once_deferred); struct once_work *w; w->key = key; schedule_work(&w->work); module unload //*the key is destroy* process_one_work once_deferred BUG_ON(!static_key_enabled(work->key)); static_key_count((struct static_key *)x) //*access key, crash* When module uses DO_ONCE mechanism, it could crash due to the above concurrency problem, we could reproduce it with link[1]. Fix it by add/put module refcount in the once work process. [1] https://lore.kernel.org/netdev/eaa6c371-465e-57eb-6be9-f4b16b9d7cbf@huawei.… Cc: Hannes Frederic Sowa <hannes(a)stressinduktion.org> Cc: Daniel Borkmann <daniel(a)iogearbox.net> Cc: David S. Miller <davem(a)davemloft.net> Cc: Eric Dumazet <edumazet(a)google.com> Reported-by: Minmin chen <chenmingmin(a)huawei.com> Signed-off-by: Kefeng Wang <wangkefeng.wang(a)huawei.com> Acked-by: Hannes Frederic Sowa <hannes(a)stressinduktion.org> Signed-off-by: David S. Miller <davem(a)davemloft.net> (cherry picked from commit 1027b96ec9d34f9abab69bc1a4dc5b1ad8ab1349) Signed-off-by: Kefeng Wang <wangkefeng.wang(a)huawei.com> Reviewed-by: Xie XiuQi <xiexiuqi(a)huawei.com> Signed-off-by: Zheng Zengkai <zhengzengkai(a)huawei.com> --- include/linux/once.h | 4 ++-- lib/once.c | 11 ++++++++--- 2 files changed, 10 insertions(+), 5 deletions(-) diff --git a/include/linux/once.h b/include/linux/once.h index 9225ee6d96c7..ae6f4eb41cbe 100644 --- a/include/linux/once.h +++ b/include/linux/once.h @@ -7,7 +7,7 @@ bool __do_once_start(bool *done, unsigned long *flags); void __do_once_done(bool *done, struct static_key_true *once_key, - unsigned long *flags); + unsigned long *flags, struct module *mod); /* Call a function exactly once. The idea of DO_ONCE() is to perform * a function call such as initialization of random seeds, etc, only @@ -46,7 +46,7 @@ void __do_once_done(bool *done, struct static_key_true *once_key, if (unlikely(___ret)) { \ func(__VA_ARGS__); \ __do_once_done(&___done, &___once_key, \ - &___flags); \ + &___flags, THIS_MODULE); \ } \ } \ ___ret; \ diff --git a/lib/once.c b/lib/once.c index 8b7d6235217e..59149bf3bfb4 100644 --- a/lib/once.c +++ b/lib/once.c @@ -3,10 +3,12 @@ #include <linux/spinlock.h> #include <linux/once.h> #include <linux/random.h> +#include <linux/module.h> struct once_work { struct work_struct work; struct static_key_true *key; + struct module *module; }; static void once_deferred(struct work_struct *w) @@ -16,10 +18,11 @@ static void once_deferred(struct work_struct *w) work = container_of(w, struct once_work, work); BUG_ON(!static_key_enabled(work->key)); static_branch_disable(work->key); + module_put(work->module); kfree(work); } -static void once_disable_jump(struct static_key_true *key) +static void once_disable_jump(struct static_key_true *key, struct module *mod) { struct once_work *w; @@ -29,6 +32,8 @@ static void once_disable_jump(struct static_key_true *key) INIT_WORK(&w->work, once_deferred); w->key = key; + w->module = mod; + __module_get(mod); schedule_work(&w->work); } @@ -53,11 +58,11 @@ bool __do_once_start(bool *done, unsigned long *flags) EXPORT_SYMBOL(__do_once_start); void __do_once_done(bool *done, struct static_key_true *once_key, - unsigned long *flags) + unsigned long *flags, struct module *mod) __releases(once_lock) { *done = true; spin_unlock_irqrestore(&once_lock, *flags); - once_disable_jump(once_key); + once_disable_jump(once_key, mod); } EXPORT_SYMBOL(__do_once_done); -- 2.20.1

1 0

[PATCH openEuler-1.0-LTS] scsi: sr: Return correct event when media event code is 3
by Yang Yingliang 16 Aug '21

16 Aug '21

From: Li Manyi <limanyi(a)uniontech.com> stable inclusion from linux-4.19.203 commit 489492b5a81f0f6de1ffa246e4183e479298fd2b -------------------------------- [ Upstream commit 5c04243a56a7977185b00400e59ca7e108004faf ] Media event code 3 is defined in the MMC-6 spec as follows: "MediaRemoval: The media has been removed from the specified slot, and the Drive is unable to access the media without user intervention. This applies to media changers only." This indicated that treating the condition as an EJECT_REQUEST was appropriate. However, doing so had the unfortunate side-effect of causing the drive tray to be physically ejected on resume. Instead treat the event as a MEDIA_CHANGE request. Fixes: 7dd753ca59d6 ("scsi: sr: Return appropriate error code when disk is ejected") Link: https://bugzilla.kernel.org/show_bug.cgi?id=213759 Link: https://lore.kernel.org/r/20210726114913.6760-1-limanyi@uniontech.com Signed-off-by: Li Manyi <limanyi(a)uniontech.com> Signed-off-by: Martin K. Petersen <martin.petersen(a)oracle.com> Signed-off-by: Sasha Levin <sashal(a)kernel.org> Reviewed-by: Jason Yan <yanaijie(a)huawei.com> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> --- drivers/scsi/sr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c index acf0c244141f4..84dd776d36c33 100644 --- a/drivers/scsi/sr.c +++ b/drivers/scsi/sr.c @@ -217,7 +217,7 @@ static unsigned int sr_get_events(struct scsi_device *sdev) else if (med->media_event_code == 2) return DISK_EVENT_MEDIA_CHANGE; else if (med->media_event_code == 3) - return DISK_EVENT_EJECT_REQUEST; + return DISK_EVENT_MEDIA_CHANGE; return 0; } -- 2.25.1

1 0

[PATCH openEuler-1.0-LTS 1/2] sctp: move the active_key update after sh_keys is added
by Yang Yingliang 16 Aug '21

16 Aug '21

From: Xin Long <lucien.xin(a)gmail.com> stable inclusion from linux-4.19.203 commit f91e7bd934c705f25dc6651e29e9c857d48a51f4 -------------------------------- [ Upstream commit ae954bbc451d267f7d60d7b49db811d5a68ebd7b ] In commit 58acd1009226 ("sctp: update active_key for asoc when old key is being replaced"), sctp_auth_asoc_init_active_key() is called to update the active_key right after the old key is deleted and before the new key is added, and it caused that the active_key could be found with the key_id. In Ying Xu's testing, the BUG_ON in sctp_auth_asoc_init_active_key() was triggered: [ ] kernel BUG at net/sctp/auth.c:416! [ ] RIP: 0010:sctp_auth_asoc_init_active_key.part.8+0xe7/0xf0 [sctp] [ ] Call Trace: [ ] sctp_auth_set_key+0x16d/0x1b0 [sctp] [ ] sctp_setsockopt.part.33+0x1ba9/0x2bd0 [sctp] [ ] __sys_setsockopt+0xd6/0x1d0 [ ] __x64_sys_setsockopt+0x20/0x30 [ ] do_syscall_64+0x5b/0x1a0 So fix it by moving the active_key update after sh_keys is added. Fixes: 58acd1009226 ("sctp: update active_key for asoc when old key is being replaced") Reported-by: Ying Xu <yinxu(a)redhat.com> Signed-off-by: Xin Long <lucien.xin(a)gmail.com> Signed-off-by: David S. Miller <davem(a)davemloft.net> Signed-off-by: Sasha Levin <sashal(a)kernel.org> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> Reviewed-by: Yue Haibing <yuehaibing(a)huawei.com> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> --- net/sctp/auth.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/net/sctp/auth.c b/net/sctp/auth.c index b2ca66c4a21d2..9e0c98df20daf 100644 --- a/net/sctp/auth.c +++ b/net/sctp/auth.c @@ -880,14 +880,18 @@ int sctp_auth_set_key(struct sctp_endpoint *ep, memcpy(key->data, &auth_key->sca_key[0], auth_key->sca_keylength); cur_key->key = key; - if (replace) { - list_del_init(&shkey->key_list); - sctp_auth_shkey_release(shkey); - if (asoc && asoc->active_key_id == auth_key->sca_keynumber) - sctp_auth_asoc_init_active_key(asoc, GFP_KERNEL); + if (!replace) { + list_add(&cur_key->key_list, sh_keys); + return 0; } + + list_del_init(&shkey->key_list); + sctp_auth_shkey_release(shkey); list_add(&cur_key->key_list, sh_keys); + if (asoc && asoc->active_key_id == auth_key->sca_keynumber) + sctp_auth_asoc_init_active_key(asoc, GFP_KERNEL); + return 0; } -- 2.25.1

1 1

[PATCH 0/9] Transplantation of KFENCE
by Xie XiuQi 16 Aug '21

16 Aug '21

Hi shang, Thanks for your patchset. Please subscribe the kernel(a)openeuler.org mailing list first, and then resend this patchset again, or your patchset would be blocked. Others who in the mailing list could not receive the emails. Click this link for subscribe mailing list: https://openeuler.org/zh/community/mailing-list/ --- Xie XiuQi On 2021/8/16 20:27, kernel-owner(a)openeuler.org wrote: > As list administrator, your authorization is requested for the > following mailing list posting: > > List: kernel(a)openeuler.org > From: 1415317271(a)qq.com > Subject: [PATCH 0/9] > > The message is being held because: > > The message is not from a list member > > At your convenience, visit your dashboard to approve or deny the > request. >

1 0

[PATCH openEuler-1.0-LTS] usb: max-3421: Prevent corruption of freed memory
by Yang Yingliang 16 Aug '21

16 Aug '21

From: Mark Tomlinson <mark.tomlinson(a)alliedtelesis.co.nz> stable inclusion from linux-4.19.199 commit 51fc12f4d37622fa0c481604833f98f11b1cac4f CVE: CVE-2021-38204 -------------------------------- commit b5fdf5c6e6bee35837e160c00ac89327bdad031b upstream. The MAX-3421 USB driver remembers the state of the USB toggles for a device/endpoint. To save SPI writes, this was only done when a new device/endpoint was being used. Unfortunately, if the old device was removed, this would cause writes to freed memory. To fix this, a simpler scheme is used. The toggles are read from hardware when a URB is completed, and the toggles are always written to hardware when any URB transaction is started. This will cause a few more SPI transactions, but no causes kernel panics. Fixes: 2d53139f3162 ("Add support for using a MAX3421E chip as a host driver.") Cc: stable <stable(a)vger.kernel.org> Signed-off-by: Mark Tomlinson <mark.tomlinson(a)alliedtelesis.co.nz> Link: https://lore.kernel.org/r/20210625031456.8632-1-mark.tomlinson@alliedtelesi… Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> Reviewed-by: Xiu Jianfeng <xiujianfeng(a)huawei.com> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> --- drivers/usb/host/max3421-hcd.c | 44 +++++++++++----------------------- 1 file changed, 14 insertions(+), 30 deletions(-) diff --git a/drivers/usb/host/max3421-hcd.c b/drivers/usb/host/max3421-hcd.c index afa321ab55fcf..4a33a18dc0b31 100644 --- a/drivers/usb/host/max3421-hcd.c +++ b/drivers/usb/host/max3421-hcd.c @@ -153,8 +153,6 @@ struct max3421_hcd { */ struct urb *curr_urb; enum scheduling_pass sched_pass; - struct usb_device *loaded_dev; /* dev that's loaded into the chip */ - int loaded_epnum; /* epnum whose toggles are loaded */ int urb_done; /* > 0 -> no errors, < 0: errno */ size_t curr_len; u8 hien; @@ -492,39 +490,17 @@ max3421_set_speed(struct usb_hcd *hcd, struct usb_device *dev) * Caller must NOT hold HCD spinlock. */ static void -max3421_set_address(struct usb_hcd *hcd, struct usb_device *dev, int epnum, - int force_toggles) +max3421_set_address(struct usb_hcd *hcd, struct usb_device *dev, int epnum) { - struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd); - int old_epnum, same_ep, rcvtog, sndtog; - struct usb_device *old_dev; + int rcvtog, sndtog; u8 hctl; - old_dev = max3421_hcd->loaded_dev; - old_epnum = max3421_hcd->loaded_epnum; - - same_ep = (dev == old_dev && epnum == old_epnum); - if (same_ep && !force_toggles) - return; - - if (old_dev && !same_ep) { - /* save the old end-points toggles: */ - u8 hrsl = spi_rd8(hcd, MAX3421_REG_HRSL); - - rcvtog = (hrsl >> MAX3421_HRSL_RCVTOGRD_BIT) & 1; - sndtog = (hrsl >> MAX3421_HRSL_SNDTOGRD_BIT) & 1; - - /* no locking: HCD (i.e., we) own toggles, don't we? */ - usb_settoggle(old_dev, old_epnum, 0, rcvtog); - usb_settoggle(old_dev, old_epnum, 1, sndtog); - } /* setup new endpoint's toggle bits: */ rcvtog = usb_gettoggle(dev, epnum, 0); sndtog = usb_gettoggle(dev, epnum, 1); hctl = (BIT(rcvtog + MAX3421_HCTL_RCVTOG0_BIT) | BIT(sndtog + MAX3421_HCTL_SNDTOG0_BIT)); - max3421_hcd->loaded_epnum = epnum; spi_wr8(hcd, MAX3421_REG_HCTL, hctl); /* @@ -532,7 +508,6 @@ max3421_set_address(struct usb_hcd *hcd, struct usb_device *dev, int epnum, * address-assignment so it's best to just always load the * address whenever the end-point changed/was forced. */ - max3421_hcd->loaded_dev = dev; spi_wr8(hcd, MAX3421_REG_PERADDR, dev->devnum); } @@ -667,7 +642,7 @@ max3421_select_and_start_urb(struct usb_hcd *hcd) struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd); struct urb *urb, *curr_urb = NULL; struct max3421_ep *max3421_ep; - int epnum, force_toggles = 0; + int epnum; struct usb_host_endpoint *ep; struct list_head *pos; unsigned long flags; @@ -777,7 +752,6 @@ max3421_select_and_start_urb(struct usb_hcd *hcd) usb_settoggle(urb->dev, epnum, 0, 1); usb_settoggle(urb->dev, epnum, 1, 1); max3421_ep->pkt_state = PKT_STATE_SETUP; - force_toggles = 1; } else max3421_ep->pkt_state = PKT_STATE_TRANSFER; } @@ -785,7 +759,7 @@ max3421_select_and_start_urb(struct usb_hcd *hcd) spin_unlock_irqrestore(&max3421_hcd->lock, flags); max3421_ep->last_active = max3421_hcd->frame_number; - max3421_set_address(hcd, urb->dev, epnum, force_toggles); + max3421_set_address(hcd, urb->dev, epnum); max3421_set_speed(hcd, urb->dev); max3421_next_transfer(hcd, 0); return 1; @@ -1380,6 +1354,16 @@ max3421_urb_done(struct usb_hcd *hcd) status = 0; urb = max3421_hcd->curr_urb; if (urb) { + /* save the old end-points toggles: */ + u8 hrsl = spi_rd8(hcd, MAX3421_REG_HRSL); + int rcvtog = (hrsl >> MAX3421_HRSL_RCVTOGRD_BIT) & 1; + int sndtog = (hrsl >> MAX3421_HRSL_SNDTOGRD_BIT) & 1; + int epnum = usb_endpoint_num(&urb->ep->desc); + + /* no locking: HCD (i.e., we) own toggles, don't we? */ + usb_settoggle(urb->dev, epnum, 0, rcvtog); + usb_settoggle(urb->dev, epnum, 1, sndtog); + max3421_hcd->curr_urb = NULL; spin_lock_irqsave(&max3421_hcd->lock, flags); usb_hcd_unlink_urb_from_ep(hcd, urb); -- 2.25.1

1 0

[PATCH kernel-4.19] net: ll_temac: Fix bug causing buffer descriptor overrun
by Yang Yingliang 16 Aug '21

16 Aug '21

From: Esben Haabendal <esben(a)geanix.com> mainline inclusion from mainline-v5.2-rc1 commit 2c9938e738a273ba315679781a9990c7d3b1831b category: bugfix bugzilla: NA CVE: CVE-2021-38207 --------------------------- As we are actually using a BD for both the skb and each frag contained in it, the oldest TX BD would be overwritten when there was exactly one BD less than needed. Signed-off-by: Esben Haabendal <esben(a)geanix.com> Signed-off-by: David S. Miller <davem(a)davemloft.net> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> Reviewed-by: Yue Haibing <yuehaibing(a)huawei.com> Reviewed-by: Xiu Jianfeng <xiujianfeng(a)huawei.com> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> --- drivers/net/ethernet/xilinx/ll_temac_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/ethernet/xilinx/ll_temac_main.c b/drivers/net/ethernet/xilinx/ll_temac_main.c index 939de185bc6b8..2caff1a5585e7 100644 --- a/drivers/net/ethernet/xilinx/ll_temac_main.c +++ b/drivers/net/ethernet/xilinx/ll_temac_main.c @@ -689,7 +689,7 @@ temac_start_xmit(struct sk_buff *skb, struct net_device *ndev) start_p = lp->tx_bd_p + sizeof(*lp->tx_bd_v) * lp->tx_bd_tail; cur_p = &lp->tx_bd_v[lp->tx_bd_tail]; - if (temac_check_tx_bd_space(lp, num_frag)) { + if (temac_check_tx_bd_space(lp, num_frag + 1)) { if (!netif_queue_stopped(ndev)) netif_stop_queue(ndev); return NETDEV_TX_BUSY; -- 2.25.1

1 0

[PATCH kernel-4.19] tcp_comp: Avoiding the null pointer problem of ctx in comp_stream_read
by Yang Yingliang 16 Aug '21

16 Aug '21

From: Wang Yufen <wangyufen(a)huawei.com> hulk inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I45UYC?from=project-issue CVE: NA ------------------------------------------------- In comp_stream_read ctx might be null, add null check to avoid oops. And delete unnecessary tcp_comp_err_abort. Signed-off-by: Wang Yufen <wangyufen(a)huawei.com> Reviewed-by: Yue Haibing <yuehaibing(a)huawei.com> Reviewed-by: Wei Yongjun <weiyongjun1(a)huawei.com> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> --- net/ipv4/tcp_comp.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/net/ipv4/tcp_comp.c b/net/ipv4/tcp_comp.c index e7f6094b5aeec..f6ebe52f3f7f7 100644 --- a/net/ipv4/tcp_comp.c +++ b/net/ipv4/tcp_comp.c @@ -723,8 +723,6 @@ static int tcp_comp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, if (!ctx->rx.decompressed) { err = tcp_comp_decompress(sk, skb); if (err < 0) { - if (err != -ENOSPC) - tcp_comp_err_abort(sk, EBADMSG); goto recv_end; } ctx->rx.decompressed = true; @@ -758,6 +756,9 @@ bool comp_stream_read(const struct sock *sk) { struct tcp_comp_context *ctx = comp_get_ctx(sk); + if (!ctx) + return false; + if (ctx->rx.pkt) return true; -- 2.25.1

1 0

[PATCH kernel-4.19 1/2] ext4: fix potential uninitialized access to retval in kmmpd
by Yang Yingliang 16 Aug '21

16 Aug '21

From: Ye Bin <yebin10(a)huawei.com> mainline inclusion from mainline-5.14-rc5 commit b66541422824cf6cf20e9a35112e9cb5d82cdf62 category: bugfix bugzilla: 175849 CVE: NA ------------------------------------------------- if (!ext4_has_feature_mmp(sb)) then retval can be unitialized before we jump to the wait_to_exit label. Fixes: 61bb4a1c417e ("ext4: fix possible UAF when remounting r/o a mmp-protected file system") Signed-off-by: Ye Bin <yebin10(a)huawei.com> Link: https://lore.kernel.org/r/20210713022728.2533770-1-yebin10@huawei.com Signed-off-by: Theodore Ts'o <tytso(a)mit.edu> Signed-off-by: Baokun Li <libaokun1(a)huawei.com> Reviewed-by: Zhang Yi <yi.zhang(a)huawei.com> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> --- fs/ext4/mmp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/ext4/mmp.c b/fs/ext4/mmp.c index 5af24925ffa83..0e9569dc02da2 100644 --- a/fs/ext4/mmp.c +++ b/fs/ext4/mmp.c @@ -138,7 +138,7 @@ static int kmmpd(void *data) unsigned mmp_check_interval; unsigned long last_update_time; unsigned long diff; - int retval; + int retval = 0; mmp_block = le64_to_cpu(es->s_mmp_block); mmp = (struct mmp_struct *)(bh->b_data); -- 2.25.1

1 1

[PATCH openEuler-1.0-LTS 1/2] blk-mq: fix hang caused by freeze/unfreeze sequence
by Yang Yingliang 16 Aug '21

16 Aug '21

From: Bob Liu <bob.liu(a)oracle.com> mainline inclusion from mainline-v5.2-rc2 commit 7996a8b5511a72465b0b286763c2d8f412b8874a category: bugfix bugzilla: 173119 CVE: NA ----------------------------------------------- The following is a description of a hang in blk_mq_freeze_queue_wait(). The hang happens on attempt to freeze a queue while another task does queue unfreeze. The root cause is an incorrect sequence of percpu_ref_resurrect() and percpu_ref_kill() and as a result those two can be swapped: CPU#0 CPU#1 ---------------- ----------------- q1 = blk_mq_init_queue(shared_tags) q2 = blk_mq_init_queue(shared_tags): blk_mq_add_queue_tag_set(shared_tags): blk_mq_update_tag_set_depth(shared_tags): list_for_each_entry() blk_mq_freeze_queue(q1) > percpu_ref_kill() > blk_mq_freeze_queue_wait() blk_cleanup_queue(q1) blk_mq_freeze_queue(q1) > percpu_ref_kill() ^^^^^^ freeze_depth can't guarantee the order blk_mq_unfreeze_queue() > percpu_ref_resurrect() > blk_mq_freeze_queue_wait() ^^^^^^ Hang here!!!! This wrong sequence raises kernel warning: percpu_ref_kill_and_confirm called more than once on blk_queue_usage_counter_release! WARNING: CPU: 0 PID: 11854 at lib/percpu-refcount.c:336 percpu_ref_kill_and_confirm+0x99/0xb0 But the most unpleasant effect is a hang of a blk_mq_freeze_queue_wait(), which waits for a zero of a q_usage_counter, which never happens because percpu-ref was reinited (instead of being killed) and stays in PERCPU state forever. How to reproduce: - "insmod null_blk.ko shared_tags=1 nr_devices=0 queue_mode=2" - cpu0: python Script.py 0; taskset the corresponding process running on cpu0 - cpu1: python Script.py 1; taskset the corresponding process running on cpu1 Script.py: ------ #!/usr/bin/python3 import os import sys while True: on = "echo 1 > /sys/kernel/config/nullb/%s/power" % sys.argv[1] off = "echo 0 > /sys/kernel/config/nullb/%s/power" % sys.argv[1] os.system(on) os.system(off) ------ This bug was first reported and fixed by Roman, previous discussion: [1] Message id: 1443287365-4244-7-git-send-email-akinobu.mita(a)gmail.com [2] Message id: 1443563240-29306-6-git-send-email-tj(a)kernel.org [3] https://patchwork.kernel.org/patch/9268199/ Reviewed-by: Hannes Reinecke <hare(a)suse.com> Reviewed-by: Ming Lei <ming.lei(a)redhat.com> Reviewed-by: Bart Van Assche <bvanassche(a)acm.org> Reviewed-by: Christoph Hellwig <hch(a)lst.de> Signed-off-by: Roman Pen <roman.penyaev(a)profitbricks.com> Signed-off-by: Bob Liu <bob.liu(a)oracle.com> Signed-off-by: Jens Axboe <axboe(a)kernel.dk> Signed-off-by: Yu Kuai <yukuai3(a)huawei.com> Reviewed-by: Hou Tao <houtao1(a)huawei.com> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> --- block/blk-core.c | 3 ++- block/blk-mq.c | 19 ++++++++++--------- include/linux/blkdev.h | 7 ++++++- 3 files changed, 18 insertions(+), 11 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index 2f66d43c476f3..b67cb175b9737 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -955,7 +955,7 @@ int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags) smp_rmb(); wait_event(q->mq_freeze_wq, - (atomic_read(&q->mq_freeze_depth) == 0 && + (!q->mq_freeze_depth && (pm || !blk_queue_pm_only(q))) || blk_queue_dying(q)); if (blk_queue_dying(q)) @@ -1071,6 +1071,7 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id, queue_flag_set_unlocked(QUEUE_FLAG_BYPASS, q); init_waitqueue_head(&q->mq_freeze_wq); + mutex_init(&q->mq_freeze_lock); /* * Init percpu_ref in atomic mode so that it's faster to shutdown. diff --git a/block/blk-mq.c b/block/blk-mq.c index 607ee5dafa2e9..0de720aa544fa 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -136,13 +136,14 @@ void blk_mq_in_flight_rw(struct request_queue *q, struct hd_struct *part, void blk_freeze_queue_start(struct request_queue *q) { - int freeze_depth; - - freeze_depth = atomic_inc_return(&q->mq_freeze_depth); - if (freeze_depth == 1) { + mutex_lock(&q->mq_freeze_lock); + if (++q->mq_freeze_depth == 1) { percpu_ref_kill(&q->q_usage_counter); + mutex_unlock(&q->mq_freeze_lock); if (q->mq_ops) blk_mq_run_hw_queues(q, false); + } else { + mutex_unlock(&q->mq_freeze_lock); } } EXPORT_SYMBOL_GPL(blk_freeze_queue_start); @@ -193,14 +194,14 @@ EXPORT_SYMBOL_GPL(blk_mq_freeze_queue); void blk_mq_unfreeze_queue(struct request_queue *q) { - int freeze_depth; - - freeze_depth = atomic_dec_return(&q->mq_freeze_depth); - WARN_ON_ONCE(freeze_depth < 0); - if (!freeze_depth) { + mutex_lock(&q->mq_freeze_lock); + q->mq_freeze_depth--; + WARN_ON_ONCE(q->mq_freeze_depth < 0); + if (!q->mq_freeze_depth) { percpu_ref_reinit(&q->q_usage_counter); wake_up_all(&q->mq_freeze_wq); } + mutex_unlock(&q->mq_freeze_lock); } EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue); diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index ad2b10c4a0797..bb0ac8cbbb4c0 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -655,7 +655,7 @@ struct request_queue { spinlock_t unused_hctx_lock; int bypass_depth; - atomic_t mq_freeze_depth; + int mq_freeze_depth; #if defined(CONFIG_BLK_DEV_BSG) bsg_job_fn *bsg_job_fn; @@ -668,6 +668,11 @@ struct request_queue { #endif struct rcu_head rcu_head; wait_queue_head_t mq_freeze_wq; + /* + * Protect concurrent access to q_usage_counter by + * percpu_ref_kill() and percpu_ref_reinit(). + */ + struct mutex mq_freeze_lock; struct percpu_ref q_usage_counter; struct list_head all_q_node; -- 2.25.1

1 1

[PATCH kernel-4.19] blk-mq: fix hang caused by freeze/unfreeze sequence
by Yang Yingliang 16 Aug '21

16 Aug '21

From: Bob Liu <bob.liu(a)oracle.com> mainline inclusion from mainline-v5.2-rc2 commit 7996a8b5511a72465b0b286763c2d8f412b8874a category: bugfix bugzilla: 173119 CVE: NA ----------------------------------------------- The following is a description of a hang in blk_mq_freeze_queue_wait(). The hang happens on attempt to freeze a queue while another task does queue unfreeze. The root cause is an incorrect sequence of percpu_ref_resurrect() and percpu_ref_kill() and as a result those two can be swapped: CPU#0 CPU#1 ---------------- ----------------- q1 = blk_mq_init_queue(shared_tags) q2 = blk_mq_init_queue(shared_tags): blk_mq_add_queue_tag_set(shared_tags): blk_mq_update_tag_set_depth(shared_tags): list_for_each_entry() blk_mq_freeze_queue(q1) > percpu_ref_kill() > blk_mq_freeze_queue_wait() blk_cleanup_queue(q1) blk_mq_freeze_queue(q1) > percpu_ref_kill() ^^^^^^ freeze_depth can't guarantee the order blk_mq_unfreeze_queue() > percpu_ref_resurrect() > blk_mq_freeze_queue_wait() ^^^^^^ Hang here!!!! This wrong sequence raises kernel warning: percpu_ref_kill_and_confirm called more than once on blk_queue_usage_counter_release! WARNING: CPU: 0 PID: 11854 at lib/percpu-refcount.c:336 percpu_ref_kill_and_confirm+0x99/0xb0 But the most unpleasant effect is a hang of a blk_mq_freeze_queue_wait(), which waits for a zero of a q_usage_counter, which never happens because percpu-ref was reinited (instead of being killed) and stays in PERCPU state forever. How to reproduce: - "insmod null_blk.ko shared_tags=1 nr_devices=0 queue_mode=2" - cpu0: python Script.py 0; taskset the corresponding process running on cpu0 - cpu1: python Script.py 1; taskset the corresponding process running on cpu1 Script.py: ------ #!/usr/bin/python3 import os import sys while True: on = "echo 1 > /sys/kernel/config/nullb/%s/power" % sys.argv[1] off = "echo 0 > /sys/kernel/config/nullb/%s/power" % sys.argv[1] os.system(on) os.system(off) ------ This bug was first reported and fixed by Roman, previous discussion: [1] Message id: 1443287365-4244-7-git-send-email-akinobu.mita(a)gmail.com [2] Message id: 1443563240-29306-6-git-send-email-tj(a)kernel.org [3] https://patchwork.kernel.org/patch/9268199/ Reviewed-by: Hannes Reinecke <hare(a)suse.com> Reviewed-by: Ming Lei <ming.lei(a)redhat.com> Reviewed-by: Bart Van Assche <bvanassche(a)acm.org> Reviewed-by: Christoph Hellwig <hch(a)lst.de> Signed-off-by: Roman Pen <roman.penyaev(a)profitbricks.com> Signed-off-by: Bob Liu <bob.liu(a)oracle.com> Signed-off-by: Jens Axboe <axboe(a)kernel.dk> Signed-off-by: Yu Kuai <yukuai3(a)huawei.com> Reviewed-by: Hou Tao <houtao1(a)huawei.com> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> --- block/blk-core.c | 3 ++- block/blk-mq.c | 19 ++++++++++--------- include/linux/blkdev.h | 7 ++++++- 3 files changed, 18 insertions(+), 11 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index 4b63336465306..34456f2bf45c3 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -955,7 +955,7 @@ int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags) smp_rmb(); wait_event(q->mq_freeze_wq, - (atomic_read(&q->mq_freeze_depth) == 0 && + (!q->mq_freeze_depth && (pm || !blk_queue_pm_only(q))) || blk_queue_dying(q)); if (blk_queue_dying(q)) @@ -1072,6 +1072,7 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id, queue_flag_set_unlocked(QUEUE_FLAG_BYPASS, q); init_waitqueue_head(&q->mq_freeze_wq); + mutex_init(&q->mq_freeze_lock); /* * Init percpu_ref in atomic mode so that it's faster to shutdown. diff --git a/block/blk-mq.c b/block/blk-mq.c index f684053ecd51f..dc96754abc2cd 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -136,13 +136,14 @@ void blk_mq_in_flight_rw(struct request_queue *q, struct hd_struct *part, void blk_freeze_queue_start(struct request_queue *q) { - int freeze_depth; - - freeze_depth = atomic_inc_return(&q->mq_freeze_depth); - if (freeze_depth == 1) { + mutex_lock(&q->mq_freeze_lock); + if (++q->mq_freeze_depth == 1) { percpu_ref_kill(&q->q_usage_counter); + mutex_unlock(&q->mq_freeze_lock); if (q->mq_ops) blk_mq_run_hw_queues(q, false); + } else { + mutex_unlock(&q->mq_freeze_lock); } } EXPORT_SYMBOL_GPL(blk_freeze_queue_start); @@ -193,14 +194,14 @@ EXPORT_SYMBOL_GPL(blk_mq_freeze_queue); void blk_mq_unfreeze_queue(struct request_queue *q) { - int freeze_depth; - - freeze_depth = atomic_dec_return(&q->mq_freeze_depth); - WARN_ON_ONCE(freeze_depth < 0); - if (!freeze_depth) { + mutex_lock(&q->mq_freeze_lock); + q->mq_freeze_depth--; + WARN_ON_ONCE(q->mq_freeze_depth < 0); + if (!q->mq_freeze_depth) { percpu_ref_reinit(&q->q_usage_counter); wake_up_all(&q->mq_freeze_wq); } + mutex_unlock(&q->mq_freeze_lock); } EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue); diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 1ce80e23eeab1..376f5dee46fce 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -660,7 +660,7 @@ struct request_queue { spinlock_t unused_hctx_lock; int bypass_depth; - atomic_t mq_freeze_depth; + int mq_freeze_depth; #if defined(CONFIG_BLK_DEV_BSG) bsg_job_fn *bsg_job_fn; @@ -673,6 +673,11 @@ struct request_queue { #endif struct rcu_head rcu_head; wait_queue_head_t mq_freeze_wq; + /* + * Protect concurrent access to q_usage_counter by + * percpu_ref_kill() and percpu_ref_reinit(). + */ + struct mutex mq_freeze_lock; struct percpu_ref q_usage_counter; struct list_head all_q_node; -- 2.25.1

1 0

[PATCH kernel-4.19 00/14] backport linux-4.19.202
by Yang Yingliang 16 Aug '21

16 Aug '21

Axel Lin (1): regulator: rt5033: Fix n_voltages settings for BUCK and LDO Daniel Jordan (2): padata: validate cpumask without removed CPU during offline padata: add separate cpuhp node for CPUHP_PADATA_DEAD Goldwyn Rodrigues (1): btrfs: mark compressed range uptodate only if all bio succeed Greg Kroah-Hartman (3): Revert "Bluetooth: Shutdown controller after workqueues are flushed or cancelled" Revert "watchdog: iTCO_wdt: Account for rebooting on second timeout" Linux 4.19.202 Guenter Roeck (1): spi: mediatek: Fix fifo transfer Jani Nikula (1): drm/i915: Ensure intel_engine_init_execlist() builds with Clang Jia He (1): qed: fix possible unpaired spin_{un}lock_bh in _qed_mcp_cmd_and_union() Kyle Russell (1): ASoC: tlv320aic31xx: fix reversed bclk/wclk master bits Pravin B Shelar (1): net: Fix zero-copy head len calculation. Sudeep Holla (1): firmware: arm_scmi: Ensure drivers provide a probe function Takashi Iwai (1): r8152: Fix potential PM refcount imbalance Makefile | 2 +- drivers/firmware/arm_scmi/bus.c | 3 +++ drivers/gpu/drm/i915/intel_engine_cs.c | 2 +- drivers/net/ethernet/qlogic/qed/qed_mcp.c | 23 ++++++++++++++----- drivers/net/usb/r8152.c | 3 ++- drivers/spi/spi-mt65xx.c | 19 ++++----------- drivers/watchdog/iTCO_wdt.c | 12 +++------- fs/btrfs/compression.c | 3 +-- include/linux/cpuhotplug.h | 1 + include/linux/mfd/rt5033-private.h | 4 ++-- include/linux/padata.h | 6 +++-- kernel/padata.c | 28 ++++++++++++++++------- net/bluetooth/hci_core.c | 16 ++++++------- net/core/skbuff.c | 5 +++- sound/soc/codecs/tlv320aic31xx.h | 4 ++-- 15 files changed, 74 insertions(+), 57 deletions(-) -- 2.25.1

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[PATCH openEuler-1.0-LTS v2 0/5] Introduce default passthrough mode for some SoCs
by Hanjun Guo 16 Aug '21

16 Aug '21

Extended the SMMU_BYPASS_DEV to support SMMU default bypass for some CPU SoCs which the SMMU is not functional well in address translation mode. This patch set based on openEuler kernel LTS 1.0. v2: Adding another patch which other four patches based on. Thanks! Cc: Guo Hui <guohui(a)uniontech.com> Cc: Cheng Jian <cj.chengjian(a)huawei.com> Cc: Zhen Lei <thunder.leizhen(a)huawei.com> Cc: Xiuqi Xie <xiexiuqi(a)huawei.com> Guo Hui (1): arm64: Add MIDR encoding for PHYTIUM CPUs Hanjun Guo (3): arm64: phytium: using MIDR_PHYTIUM_FT2000PLUS instead of ARM_CPU_IMP_PHYTIUM iommu: dev_bypass: cleanup dev bypass code iommu: smmuv2: Using the SMMU_BYPASS_DEV to bypass SMMU for some SoCs Weilong Chen (1): arm64: Add MIDR encoding for HiSilicon Taishan CPUs arch/arm64/include/asm/cputype.h | 7 +++++++ arch/arm64/kernel/topology.c | 6 +++--- drivers/iommu/Kconfig | 14 +++++++++++--- drivers/iommu/arm-smmu-v3.c | 2 +- drivers/iommu/arm-smmu.c | 28 ++++++++++++++++++++++++++++ drivers/iommu/iommu.c | 13 ++++--------- drivers/usb/host/xhci-pci.c | 4 +++- 7 files changed, 57 insertions(+), 17 deletions(-) -- 1.7.12.4

1 5

[PATCH kernel-4.19 0/4] Introduce default passthrough mode for some SoCs
by Hanjun Guo 16 Aug '21

16 Aug '21

Extended the SMMU_BYPASS_DEV to support SMMU default bypass for some CPU SoCs which the SMMU is not functional well in address translation mode. This is the version for 4.19 kernel. Guo Hui, if you didn't test patchset based on 1.0 LTS kernel, you can just apply this patch set instead. Thanks! Cc: Guo Hui <guohui(a)uniontech.com> Cc: Cheng Jian <cj.chengjian(a)huawei.com> Cc: Zhen Lei <thunder.leizhen(a)huawei.com> Cc: Xiuqi Xie <xiexiuqi(a)huawei.com> Guo Hui (1): arm64: Add MIDR encoding for PHYTIUM CPUs Hanjun Guo (3): arm64: phytium: using MIDR_PHYTIUM_FT2000PLUS instead of ARM_CPU_IMP_PHYTIUM iommu: dev_bypass: cleanup dev bypass code iommu: smmuv2: Using the SMMU_BYPASS_DEV to bypass SMMU for some SoCs arch/arm64/include/asm/cputype.h | 5 +++++ arch/arm64/kernel/topology.c | 6 +++--- drivers/iommu/Kconfig | 14 +++++++++++--- drivers/iommu/arm-smmu-v3.c | 2 +- drivers/iommu/arm-smmu.c | 28 ++++++++++++++++++++++++++++ drivers/iommu/iommu.c | 13 ++++--------- drivers/usb/host/xhci-pci.c | 4 +++- 7 files changed, 55 insertions(+), 17 deletions(-) -- 1.7.12.4

1 4

[PATCH openEuler-1.0-LTS 0/4] Introduce default passthrough mode for some SoCs
by Hanjun Guo 16 Aug '21

16 Aug '21

Extended the SMMU_BYPASS_DEV to support SMMU default bypass for some CPU SoCs which the SMMU is not functional well in address translation mode. This patch set based on openEuler kernel LTS 1.0 Guo Hui, could you please test this patch set? as it's based on openEuler kernel LTS 1.0, you can apply patches 2~4/4 for 4.19 kernel. Thanks! Cc: Guo Hui <guohui(a)uniontech.com> Cc: Cheng Jian <cj.chengjian(a)huawei.com> Cc: Zhen Lei <thunder.leizhen(a)huawei.com> Cc: Xiuqi Xie <xiexiuqi(a)huawei.com> Guo Hui (1): arm64: Add MIDR encoding for PHYTIUM CPUs Hanjun Guo (3): arm64: phytium: using MIDR_PHYTIUM_FT2000PLUS instead of ARM_CPU_IMP_PHYTIUM iommu: dev_bypass: cleanup dev bypass code iommu: smmuv2: Using the SMMU_BYPASS_DEV to bypass SMMU for some SoCs arch/arm64/include/asm/cputype.h | 5 +++++ arch/arm64/kernel/topology.c | 6 +++--- drivers/iommu/Kconfig | 14 +++++++++++--- drivers/iommu/arm-smmu-v3.c | 2 +- drivers/iommu/arm-smmu.c | 28 ++++++++++++++++++++++++++++ drivers/iommu/iommu.c | 13 ++++--------- drivers/usb/host/xhci-pci.c | 4 +++- 7 files changed, 55 insertions(+), 17 deletions(-) -- 1.7.12.4

1 5

[PATCH kernel-4.19] config: Enable CONFIG_UCE_KERNEL_RECOVERY by default
by Yang Yingliang 16 Aug '21

16 Aug '21

hulk inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I44REB CVE: NA -------------------------------- Enable CONFIG_UCE_KERNEL_RECOVERY by default. Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> --- arch/arm64/configs/hulk_defconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/configs/hulk_defconfig b/arch/arm64/configs/hulk_defconfig index 19cb619927129..c340b5408e9d3 100644 --- a/arch/arm64/configs/hulk_defconfig +++ b/arch/arm64/configs/hulk_defconfig @@ -548,6 +548,7 @@ CONFIG_CPU_PM=y CONFIG_ARCH_HIBERNATION_POSSIBLE=y CONFIG_ARCH_HIBERNATION_HEADER=y CONFIG_ARCH_SUSPEND_POSSIBLE=y +CONFIG_UCE_KERNEL_RECOVERY=y # # CPU Power Management -- 2.25.1

1 0

[PATCH kernel-4.19] EDAC/ghes: Remove intermediate buffer pvt->detail_location
by Yang Yingliang 16 Aug '21

16 Aug '21

From: Robert Richter <rrichter(a)marvell.com> mainline inclusion from mainline-v5.4-rc1 commit 501eb40 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I45QJK?from=project-issue CVE: NA -------------------------------- detail_location[] is used to collect two location strings so they can be passed as one to trace_mc_event(). Instead of having an extra copy step, assemble the location string in other_detail[] from the beginning. Using other_detail[] to call trace_mc_event() is now the same as in edac_mc.c and code can be unified. Signed-off-by: Robert Richter <rrichter(a)marvell.com> Signed-off-by: Borislav Petkov <bp(a)suse.de> Reviewed-by: James Morse <james.morse(a)arm.com> Reviewed-by: Mauro Carvalho Chehab <mchehab+samsung(a)kernel.org> Cc: "linux-edac(a)vger.kernel.org" <linux-edac(a)vger.kernel.org> Cc: Tony Luck <tony.luck(a)intel.com> Link: https://lkml.kernel.org/r/20191106093239.25517-12-rrichter@marvell.com Signed-off-by: Xiongfeng Wang <wangxiongfeng2(a)huawei.com> Reviewed-by: Hanjun Guo <guohanjun(a)huawei.com> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> --- drivers/edac/ghes_edac.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/drivers/edac/ghes_edac.c b/drivers/edac/ghes_edac.c index 78c339da19b56..f7f8feb4498bc 100644 --- a/drivers/edac/ghes_edac.c +++ b/drivers/edac/ghes_edac.c @@ -23,8 +23,7 @@ struct ghes_edac_pvt { struct mem_ctl_info *mci; /* Buffers for the error handling routine */ - char detail_location[240]; - char other_detail[160]; + char other_detail[400]; char msg[80]; }; @@ -340,6 +339,8 @@ void ghes_edac_report_mem_error(int sev, struct cper_sec_mem_err *mem_err) /* All other fields are mapped on e->other_detail */ p = pvt->other_detail; + p += snprintf(p, sizeof(pvt->other_detail), + "APEI location: %s ", e->location); if (mem_err->validation_bits & CPER_MEM_VALID_ERROR_STATUS) { u64 status = mem_err->error_status; @@ -420,12 +421,10 @@ void ghes_edac_report_mem_error(int sev, struct cper_sec_mem_err *mem_err) grain_bits = fls_long(e->grain - 1); /* Generate the trace event */ - snprintf(pvt->detail_location, sizeof(pvt->detail_location), - "APEI location: %s %s", e->location, e->other_detail); trace_mc_event(type, e->msg, e->label, e->error_count, mci->mc_idx, e->top_layer, e->mid_layer, e->low_layer, (e->page_frame_number << PAGE_SHIFT) | e->offset_in_page, - grain_bits, e->syndrome, pvt->detail_location); + grain_bits, e->syndrome, e->other_detail); edac_raw_mc_handle_error(type, mci, e); spin_unlock_irqrestore(&ghes_lock, flags); -- 2.25.1

1 0

[PATCH openEuler-21.09 1/3] USB: Fix some clerical mistakes
by Zheng Zengkai 13 Aug '21

13 Aug '21

From: LeoLiu-oc <LeoLiu-oc(a)zhaoxin.com> zhaoxin inclusion category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I40QDN CVE: NA ---------------------------------------------------------------- Fix some clerical mistakes in previous patch. Fixes: 4d79e0478e4d ("USB:Fix kernel NULL pointer when unbind UHCI form vfio-pci") Signed-off-by: LeoLiu-oc <LeoLiu-oc(a)zhaoxin.com> Signed-off-by: Zheng Zengkai <zhengzengkai(a)huawei.com> Reviewed-by: Xie XiuQi <xiexiuqi(a)huawei.com> --- drivers/usb/core/hcd-pci.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c index 000ee7a6731f..bbf9bd2d4b08 100644 --- a/drivers/usb/core/hcd-pci.c +++ b/drivers/usb/core/hcd-pci.c @@ -67,8 +67,8 @@ static void for_each_companion(struct pci_dev *pdev, struct usb_hcd *hcd, continue; if (strncmp(drv->name, "uhci_hcd", sizeof("uhci_hcd") - 1) && - strncmp(drv->name, "ooci_hcd", sizeof("uhci_hcd") - 1) && - strncmp(drv->name, "ehci_hcd", sizeof("uhci_hcd") - 1)) + strncmp(drv->name, "ohci-pci", sizeof("ohci-pci") - 1) && + strncmp(drv->name, "ehci-pci", sizeof("ehci-pci") - 1)) continue; /* -- 2.20.1

1 2

回复：Re: [PATCH kernel-4.19] init/main.c:add cputype phytium FT2500 and add iommu.passthrough-on
by guohui＠uniontech.com 13 Aug '21

13 Aug '21

1 0

[PATCH kernel-4.19] init/main.c:add cputype phytium FT2500 and add iommu.passthrough-on
by Guo Hui 13 Aug '21

13 Aug '21

uniontech inclusion category: bugfix bugzilla: NA CVE: NA Due to a problem with the IOMMU hardware of Phytium S2500/FT-2500, running the following commands on a Phytium S2500/FT-2500 machine will cause the system to hang "dd if=/dev/zero of=tmp.img bs=1M count=409600" and "I/O error" will be printed in the console. This patch can solve the problem on Phytium S2500/FT-2500 by passthrough IOMMU.After installing the kernel using this patch, use the following command to check the parameter "iommu.passthrough=on": "cat /proc/cmdline" Signed-off-by: Guo Hui <guohui(a)uniontech.com> --- arch/arm64/include/asm/cputype.h | 4 ++++ init/main.c | 16 ++++++++++++++++ 2 files changed, 20 insertions(+) diff --git a/arch/arm64/include/asm/cputype.h b/arch/arm64/include/asm/cputype.h index f33947af79d9..32687e4316fb 100644 --- a/arch/arm64/include/asm/cputype.h +++ b/arch/arm64/include/asm/cputype.h @@ -85,6 +85,8 @@ #define APM_CPU_PART_POTENZA 0x000 +#define PHYTIUM_CPU_PART_2500 0X663 + #define CAVIUM_CPU_PART_THUNDERX 0x0A1 #define CAVIUM_CPU_PART_THUNDERX_81XX 0x0A2 #define CAVIUM_CPU_PART_THUNDERX_83XX 0x0A3 @@ -123,6 +125,8 @@ #define MIDR_NVIDIA_CARMEL MIDR_CPU_MODEL(ARM_CPU_IMP_NVIDIA, NVIDIA_CPU_PART_CARMEL) #define MIDR_HISI_TSV110 MIDR_CPU_MODEL(ARM_CPU_IMP_HISI, HISI_CPU_PART_TSV110) #define MIDR_HISI_TSV200 MIDR_CPU_MODEL(ARM_CPU_IMP_HISI, HISI_CPU_PART_TSV200) +#define MIDR_FT_2500 MIDR_CPU_MODEL(ARM_CPU_IMP_PHYTIUM, \ + PHYTIUM_CPU_PART_2500) #ifndef __ASSEMBLY__ diff --git a/init/main.c b/init/main.c index c149972b46ad..388d6bd3b5b3 100644 --- a/init/main.c +++ b/init/main.c @@ -473,6 +473,22 @@ void __init parse_early_param(void) static int done __initdata; static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata; +#ifdef CONFIG_ARM_GIC_PHYTIUM_2500 + if ((read_cpuid_id() & MIDR_CPU_MODEL_MASK) == MIDR_FT_2500) { + char *iommu_cmd = " iommu.passthrough=on"; + int iommu_cmd_len = strlen(iommu_cmd); + int boot_cmd_line_len = strlen(boot_command_line); + int last_args_len = COMMAND_LINE_SIZE - boot_cmd_line_len; + + if (last_args_len >= (iommu_cmd_len + 1)) { + pr_info("FT S2500 iommu type: IOMMU_DOMAIN_IDENTITY"); + strncat(boot_command_line, iommu_cmd, iommu_cmd_len); + } else { + pr_err("FT S2500 boot_cmd_line is too long, add 'iommu.passthrough=on' failed."); + } + } +#endif + if (done) return; -- 2.20.1

2 1

[PATCH openEuler-1.0-LTS] USB: fix some clerical mistakes
by Cheng Jian 12 Aug '21

12 Aug '21

From: LeoLiu-oc <LeoLiu-oc(a)zhaoxin.com> zhaoxin inclusion category: feature bugzilla: https://bugzilla.openeuler.org/show_bug.cgi?id=19 CVE: NA ---------------------------------------------------------------- Fix some clerical mistakes in previous Signed-off-by: LeoLiu-oc <LeoLiu-oc(a)zhaoxin.com> Reviewed-by: Xie XiuQi <xiexiuqi(a)huawei.com> --- drivers/usb/core/hcd-pci.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c index c3cddaab708d..d4234f81b791 100644 --- a/drivers/usb/core/hcd-pci.c +++ b/drivers/usb/core/hcd-pci.c @@ -67,8 +67,8 @@ static void for_each_companion(struct pci_dev *pdev, struct usb_hcd *hcd, continue; if (strncmp(drv->name, "uhci_hcd", sizeof("uhci_hcd") - 1) && - strncmp(drv->name, "ooci_hcd", sizeof("uhci_hcd") - 1) && - strncmp(drv->name, "ehci_hcd", sizeof("uhci_hcd") - 1)) + strncmp(drv->name, "ohci-pci", sizeof("ohci-pci") - 1) && + strncmp(drv->name, "ehci-pci", sizeof("ehci-pci") - 1)) continue; /* -- 2.25.1

1 0

[PATCH kernel-4.19] USB: fix some clerical mistakes
by Cheng Jian 12 Aug '21

12 Aug '21

From: LeoLiu-oc <LeoLiu-oc(a)zhaoxin.com> zhaoxin inclusion category: feature bugzilla: https://bugzilla.openeuler.org/show_bug.cgi?id=19 CVE: NA ---------------------------------------------------------------- Fix some clerical mistakes in previous Signed-off-by: LeoLiu-oc <LeoLiu-oc(a)zhaoxin.com> Reviewed-by: Xie XiuQi <xiexiuqi(a)huawei.com> --- drivers/usb/core/hcd-pci.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c index c3cddaab708d..d4234f81b791 100644 --- a/drivers/usb/core/hcd-pci.c +++ b/drivers/usb/core/hcd-pci.c @@ -67,8 +67,8 @@ static void for_each_companion(struct pci_dev *pdev, struct usb_hcd *hcd, continue; if (strncmp(drv->name, "uhci_hcd", sizeof("uhci_hcd") - 1) && - strncmp(drv->name, "ooci_hcd", sizeof("uhci_hcd") - 1) && - strncmp(drv->name, "ehci_hcd", sizeof("uhci_hcd") - 1)) + strncmp(drv->name, "ohci-pci", sizeof("ohci-pci") - 1) && + strncmp(drv->name, "ehci-pci", sizeof("ehci-pci") - 1)) continue; /* -- 2.25.1

1 0

[PATCH openEuler-21.03] usb: cdns3: Fix runtime PM imbalance on error
by Xu Zehui 12 Aug '21

12 Aug '21

From: Dinghao Liu <dinghao.liu(a)zju.edu.cn> stable inclusion from stable-v5.10.44 commit 2f523cd4a9311cba629facc7d353eabbd492bd5b bugzilla: https://bugzilla.openeuler.org/show_bug.cgi?id=345 CVE: NA -------------------------------- [ Upstream commit 07adc0225484fc199e3dc15ec889f75f498c4fca ] When cdns3_gadget_start() fails, a pairing PM usage counter decrement is needed to keep the counter balanced. Signed-off-by: Dinghao Liu <dinghao.liu(a)zju.edu.cn> Link: https://lore.kernel.org/r/20210412054908.7975-1-dinghao.liu@zju.edu.cn Signed-off-by: Peter Chen <peter.chen(a)kernel.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> Signed-off-by: Xu Zehui <zehuixu(a)whu.edu.cn> --- drivers/usb/cdns3/gadget.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/usb/cdns3/gadget.c b/drivers/usb/cdns3/gadget.c index 0aa85cc07ff1..c24c0e3440e3 100644 --- a/drivers/usb/cdns3/gadget.c +++ b/drivers/usb/cdns3/gadget.c @@ -3255,8 +3255,10 @@ static int __cdns3_gadget_init(struct cdns3 *cdns) pm_runtime_get_sync(cdns->dev); ret = cdns3_gadget_start(cdns); - if (ret) + if (ret) { + pm_runtime_put_sync(cdns->dev); return ret; + } /* * Because interrupt line can be shared with other components in -- 2.25.1

2 1

[kernel-4.19 v2 0/2] uce feature support
by Tong Tiangen 12 Aug '21

12 Aug '21

v2->v1: fix typo. Tong Tiangen (2): uce: cow scenario support kernel recovery uce: pagecache reading scenario support kernel recovery arch/arm64/Kconfig | 10 + arch/arm64/include/asm/exception.h | 12 ++ arch/arm64/include/asm/page.h | 8 + arch/arm64/include/asm/thread_info.h | 8 + arch/arm64/include/asm/uaccess.h | 8 + arch/arm64/kernel/ras.c | 7 + arch/arm64/lib/copy_page.S | 78 ++++++++ arch/arm64/lib/copy_template_generic_read.S | 193 ++++++++++++++++++++ arch/arm64/lib/copy_to_user.S | 19 ++ arch/arm64/mm/copypage.c | 14 ++ arch/arm64/mm/fault.c | 160 ++++++++++++++++ include/linux/highmem.h | 17 ++ include/linux/kernel.h | 4 + include/linux/mm.h | 3 + include/linux/uio.h | 5 + kernel/sysctl.c | 13 ++ lib/iov_iter.c | 132 +++++++++++++ mm/filemap.c | 8 +- mm/internal.h | 6 + mm/memory-failure.c | 7 + mm/memory.c | 8 + 21 files changed, 719 insertions(+), 1 deletion(-) create mode 100644 arch/arm64/lib/copy_template_generic_read.S -- 2.18.0.huawei.25

2 3

[openEuler-1.0-LTS v2 0/2] uce feature support
by Tong Tiangen 12 Aug '21

12 Aug '21

2 3

[PATCH openEuler-1.0-LTS] kernel/hung_task.c: introduce sysctl to print all traces when a hung task is detected
by Bixuan Cui 12 Aug '21

12 Aug '21

From: "Guilherme G. Piccoli" <gpiccoli(a)canonical.com> Commit 401c636a0eeb ("kernel/hung_task.c: show all hung tasks before panic") introduced a change in that we started to show all CPUs backtraces when a hung task is detected _and_ the sysctl/kernel parameter "hung_task_panic" is set. The idea is good, because usually when observing deadlocks (that may lead to hung tasks), the culprit is another task holding a lock and not necessarily the task detected as hung. The problem with this approach is that dumping backtraces is a slightly expensive task, specially printing that on console (and specially in many CPU machines, as servers commonly found nowadays). So, users that plan to collect a kdump to investigate the hung tasks and narrow down the deadlock definitely don't need the CPUs backtrace on dmesg/console, which will delay the panic and pollute the log (crash tool would easily grab all CPUs traces with 'bt -a' command). Also, there's the reciprocal scenario: some users may be interested in seeing the CPUs backtraces but not have the system panic when a hung task is detected. The current approach hence is almost as embedding a policy in the kernel, by forcing the CPUs backtraces' dump (only) on hung_task_panic. This patch decouples the panic event on hung task from the CPUs backtraces dump, by creating (and documenting) a new sysctl called "hung_task_all_cpu_backtrace", analog to the approach taken on soft/hard lockups, that have both a panic and an "all_cpu_backtrace" sysctl to allow individual control. The new mechanism for dumping the CPUs backtraces on hung task detection respects "hung_task_warnings" by not dumping the traces in case there's no warnings left. Signed-off-by: Guilherme G. Piccoli <gpiccoli(a)canonical.com> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Reviewed-by: Kees Cook <keescook(a)chromium.org> Cc: Tetsuo Handa <penguin-kernel(a)I-love.SAKURA.ne.jp> Link: http://lkml.kernel.org/r/20200327223646.20779-1-gpiccoli@canonical.com Signed-off-by: Linus Torvalds <torvalds(a)linux-foundation.org> Signed-off-by: Bixuan Cui <cuibixuan(a)huawei.com> --- Documentation/sysctl/kernel.txt | 14 ++++++++++++++ include/linux/sched/sysctl.h | 7 +++++++ kernel/hung_task.c | 20 ++++++++++++++++++-- kernel/sysctl.c | 11 +++++++++++ 4 files changed, 50 insertions(+), 2 deletions(-) diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt index f41ae5a3cc8d..7e33d039ea17 100644 --- a/Documentation/sysctl/kernel.txt +++ b/Documentation/sysctl/kernel.txt @@ -337,6 +337,20 @@ Default value is "/sbin/hotplug". ============================================================== +hung_task_all_cpu_backtrace: + +If this option is set, the kernel will send an NMI to all CPUs to dump +their backtraces when a hung task is detected. This file shows up if +CONFIG_DETECT_HUNG_TASK and CONFIG_SMP are enabled. + +0: Won't show all CPUs backtraces when a hung task is detected. +This is the default behavior. + +1: Will non-maskably interrupt all CPUs and dump their backtraces when +a hung task is detected. + +============================================================== + hung_task_panic: Controls the kernel's behavior when a hung task is detected. diff --git a/include/linux/sched/sysctl.h b/include/linux/sched/sysctl.h index 4993c00824a3..cabdc1ed134a 100644 --- a/include/linux/sched/sysctl.h +++ b/include/linux/sched/sysctl.h @@ -7,6 +7,13 @@ struct ctl_table; #ifdef CONFIG_DETECT_HUNG_TASK + +#ifdef CONFIG_SMP +extern unsigned int sysctl_hung_task_all_cpu_backtrace; +#else +#define sysctl_hung_task_all_cpu_backtrace 2 +#endif /* CONFIG_SMP */ + extern int sysctl_hung_task_check_count; extern unsigned int sysctl_hung_task_panic; extern unsigned long sysctl_hung_task_timeout_secs; diff --git a/kernel/hung_task.c b/kernel/hung_task.c index 4a9191617076..8a2842bfa4e1 100644 --- a/kernel/hung_task.c +++ b/kernel/hung_task.c @@ -51,9 +51,18 @@ int __read_mostly sysctl_hung_task_warnings = 10; static int __read_mostly did_panic; static bool hung_task_show_lock; static bool hung_task_call_panic; +static bool hung_task_show_all_bt; static struct task_struct *watchdog_task; +#ifdef CONFIG_SMP +/* + * Should we dump all CPUs backtraces in a hung task event? + * Defaults to 0, can be changed via sysctl. + */ +unsigned int __read_mostly sysctl_hung_task_all_cpu_backtrace; +#endif /* CONFIG_SMP */ + /* * Should we panic (and reboot, if panic_timeout= is set) when a * hung task is detected: @@ -135,6 +144,9 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout) " disables this message.\n"); sched_show_task(t); hung_task_show_lock = true; + + if (sysctl_hung_task_all_cpu_backtrace) + hung_task_show_all_bt = true; } touch_nmi_watchdog(); @@ -199,10 +211,14 @@ static void check_hung_uninterruptible_tasks(unsigned long timeout) rcu_read_unlock(); if (hung_task_show_lock) debug_show_all_locks(); - if (hung_task_call_panic) { + + if (hung_task_show_all_bt) { + hung_task_show_all_bt = false; trigger_all_cpu_backtrace(); - panic("hung_task: blocked tasks"); } + + if (hung_task_call_panic) + panic("hung_task: blocked tasks"); } static long hung_timeout_jiffies(unsigned long last_checked, diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 1733b8c71b11..dbd8ef22a48b 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -1070,6 +1070,17 @@ static struct ctl_table kern_table[] = { }, #endif #ifdef CONFIG_DETECT_HUNG_TASK +#ifdef CONFIG_SMP + { + .procname = "hung_task_all_cpu_backtrace", + .data = &sysctl_hung_task_all_cpu_backtrace, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = &zero, + .extra2 = &one, + }, +#endif /* CONFIG_SMP */ { .procname = "hung_task_panic", .data = &sysctl_hung_task_panic, -- 2.17.1

1 0

[PATCH OLK-5.10] kernel/hung_task.c: introduce sysctl to print all traces when a hung task is detected
by Bixuan Cui 12 Aug '21

12 Aug '21

From: "Guilherme G. Piccoli" <gpiccoli(a)canonical.com> Commit 401c636a0eeb ("kernel/hung_task.c: show all hung tasks before panic") introduced a change in that we started to show all CPUs backtraces when a hung task is detected _and_ the sysctl/kernel parameter "hung_task_panic" is set. The idea is good, because usually when observing deadlocks (that may lead to hung tasks), the culprit is another task holding a lock and not necessarily the task detected as hung. The problem with this approach is that dumping backtraces is a slightly expensive task, specially printing that on console (and specially in many CPU machines, as servers commonly found nowadays). So, users that plan to collect a kdump to investigate the hung tasks and narrow down the deadlock definitely don't need the CPUs backtrace on dmesg/console, which will delay the panic and pollute the log (crash tool would easily grab all CPUs traces with 'bt -a' command). Also, there's the reciprocal scenario: some users may be interested in seeing the CPUs backtraces but not have the system panic when a hung task is detected. The current approach hence is almost as embedding a policy in the kernel, by forcing the CPUs backtraces' dump (only) on hung_task_panic. This patch decouples the panic event on hung task from the CPUs backtraces dump, by creating (and documenting) a new sysctl called "hung_task_all_cpu_backtrace", analog to the approach taken on soft/hard lockups, that have both a panic and an "all_cpu_backtrace" sysctl to allow individual control. The new mechanism for dumping the CPUs backtraces on hung task detection respects "hung_task_warnings" by not dumping the traces in case there's no warnings left. Signed-off-by: Guilherme G. Piccoli <gpiccoli(a)canonical.com> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Reviewed-by: Kees Cook <keescook(a)chromium.org> Cc: Tetsuo Handa <penguin-kernel(a)I-love.SAKURA.ne.jp> Link: http://lkml.kernel.org/r/20200327223646.20779-1-gpiccoli@canonical.com Signed-off-by: Linus Torvalds <torvalds(a)linux-foundation.org> Signed-off-by: Bixuan Cui <cuibixuan(a)huawei.com> --- Documentation/sysctl/kernel.txt | 14 ++++++++++++++ include/linux/sched/sysctl.h | 7 +++++++ kernel/hung_task.c | 20 ++++++++++++++++++-- kernel/sysctl.c | 11 +++++++++++ 4 files changed, 50 insertions(+), 2 deletions(-) diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt index f41ae5a3cc8d..7e33d039ea17 100644 --- a/Documentation/sysctl/kernel.txt +++ b/Documentation/sysctl/kernel.txt @@ -337,6 +337,20 @@ Default value is "/sbin/hotplug". ============================================================== +hung_task_all_cpu_backtrace: + +If this option is set, the kernel will send an NMI to all CPUs to dump +their backtraces when a hung task is detected. This file shows up if +CONFIG_DETECT_HUNG_TASK and CONFIG_SMP are enabled. + +0: Won't show all CPUs backtraces when a hung task is detected. +This is the default behavior. + +1: Will non-maskably interrupt all CPUs and dump their backtraces when +a hung task is detected. + +============================================================== + hung_task_panic: Controls the kernel's behavior when a hung task is detected. diff --git a/include/linux/sched/sysctl.h b/include/linux/sched/sysctl.h index 4993c00824a3..cabdc1ed134a 100644 --- a/include/linux/sched/sysctl.h +++ b/include/linux/sched/sysctl.h @@ -7,6 +7,13 @@ struct ctl_table; #ifdef CONFIG_DETECT_HUNG_TASK + +#ifdef CONFIG_SMP +extern unsigned int sysctl_hung_task_all_cpu_backtrace; +#else +#define sysctl_hung_task_all_cpu_backtrace 2 +#endif /* CONFIG_SMP */ + extern int sysctl_hung_task_check_count; extern unsigned int sysctl_hung_task_panic; extern unsigned long sysctl_hung_task_timeout_secs; diff --git a/kernel/hung_task.c b/kernel/hung_task.c index 4a9191617076..8a2842bfa4e1 100644 --- a/kernel/hung_task.c +++ b/kernel/hung_task.c @@ -51,9 +51,18 @@ int __read_mostly sysctl_hung_task_warnings = 10; static int __read_mostly did_panic; static bool hung_task_show_lock; static bool hung_task_call_panic; +static bool hung_task_show_all_bt; static struct task_struct *watchdog_task; +#ifdef CONFIG_SMP +/* + * Should we dump all CPUs backtraces in a hung task event? + * Defaults to 0, can be changed via sysctl. + */ +unsigned int __read_mostly sysctl_hung_task_all_cpu_backtrace; +#endif /* CONFIG_SMP */ + /* * Should we panic (and reboot, if panic_timeout= is set) when a * hung task is detected: @@ -135,6 +144,9 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout) " disables this message.\n"); sched_show_task(t); hung_task_show_lock = true; + + if (sysctl_hung_task_all_cpu_backtrace) + hung_task_show_all_bt = true; } touch_nmi_watchdog(); @@ -199,10 +211,14 @@ static void check_hung_uninterruptible_tasks(unsigned long timeout) rcu_read_unlock(); if (hung_task_show_lock) debug_show_all_locks(); - if (hung_task_call_panic) { + + if (hung_task_show_all_bt) { + hung_task_show_all_bt = false; trigger_all_cpu_backtrace(); - panic("hung_task: blocked tasks"); } + + if (hung_task_call_panic) + panic("hung_task: blocked tasks"); } static long hung_timeout_jiffies(unsigned long last_checked, diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 1733b8c71b11..dbd8ef22a48b 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -1070,6 +1070,17 @@ static struct ctl_table kern_table[] = { }, #endif #ifdef CONFIG_DETECT_HUNG_TASK +#ifdef CONFIG_SMP + { + .procname = "hung_task_all_cpu_backtrace", + .data = &sysctl_hung_task_all_cpu_backtrace, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = &zero, + .extra2 = &one, + }, +#endif /* CONFIG_SMP */ { .procname = "hung_task_panic", .data = &sysctl_hung_task_panic, -- 2.17.1

1 0

[PATCH kernel-4.19] selinux: fix NULL dereference in policydb_destroy()
by Yang Yingliang 12 Aug '21

12 Aug '21

From: Ondrej Mosnacek <omosnace(a)redhat.com> mainline inclusion from master commit 6a1afffb08ce5f9fb9ccc20f7ab24846c0142984 category: bugfix bugzilla: 120851 CVE: NA --------------------------- The conversion to kvmalloc() forgot to account for the possibility that p->type_attr_map_array might be null in policydb_destroy(). Fix this by destroying its contents only if it is not NULL. Also make sure ebitmap_init() is called on all entries before policydb_destroy() can be called. Right now this is a no-op, because both kvcalloc() and ebitmap_init() just zero out the whole struct, but let's rather not rely on a specific implementation. Reported-by: syzbot+a57b2aff60832666fc28(a)syzkaller.appspotmail.com Fixes: acdf52d97f82 ("selinux: convert to kvmalloc") Signed-off-by: Ondrej Mosnacek <omosnace(a)redhat.com> Acked-by: Stephen Smalley <sds(a)tycho.nsa.gov> Signed-off-by: Paul Moore <paul(a)paul-moore.com> Signed-off-by: Wang Weiyang <wangweiyang2(a)huawei.com> Conflicts: security/selinux/ss/policydb.c [ acdf52d97f82 is not applied so only half of this commit is used ] Reviewed-by: Xiu Jianfeng <xiujianfeng(a)huawei.com> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> --- security/selinux/ss/policydb.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c index 91d259c87d10c..7fae43da8a647 100644 --- a/security/selinux/ss/policydb.c +++ b/security/selinux/ss/policydb.c @@ -2552,11 +2552,17 @@ int policydb_read(struct policydb *p, void *fp) if (rc) goto bad; + /* just in case ebitmap_init() becomes more than just a memset(0): */ for (i = 0; i < p->p_types.nprim; i++) { struct ebitmap *e = flex_array_get(p->type_attr_map_array, i); BUG_ON(!e); ebitmap_init(e); + } + + for (i = 0; i < p->p_types.nprim; i++) { + struct ebitmap *e = flex_array_get(p->type_attr_map_array, i); + if (p->policyvers >= POLICYDB_VERSION_AVTAB) { rc = ebitmap_read(e, fp); if (rc) -- 2.25.1

1 0

Re: [kernel-4.19 2/2] uce: pagecache reading scenario support kernel recovery
by Xie XiuQi 11 Aug '21

11 Aug '21

Hi, Thanks for your patches. Overall it looks good to me, but it also needs committer's reviewed-by from memory and fs subsystem. Reviewed-by: Xie XiuQi <xiexiuqi(a)huawei.com> On 2021/8/11 11:37, Tong Tiangen wrote: > hulk inclusion > category: feature > bugzilla: https://gitee.com/openeuler/kernel/issues/I44REB > CVE: NA > > --------------------------- > > Support pagecache reading triggered by user-mode file access scenario > to kernel recovery. > > At the same time, in this patch, we solved the problem of process D > state caused by waiting for PG_writeback in memory_failure() (the > background writeback thread timed out while writing back to the disk on > the page with hardware error). In this case, our processing method is > panic system to avoid the business interruption for a long time caused > by the business process in D state. > > Signed-off-by: Tong Tiangen <tongtiangen(a)huawei.com> > Signed-off-by: Chen Huang <chenhuang5(a)huawei.com> > --- > arch/arm64/include/asm/exception.h | 1 + > arch/arm64/include/asm/thread_info.h | 8 + > arch/arm64/include/asm/uaccess.h | 8 + > arch/arm64/kernel/ras.c | 7 + > arch/arm64/lib/copy_template_generic_read.S | 193 ++++++++++++++++++++ > arch/arm64/lib/copy_to_user.S | 19 ++ > arch/arm64/mm/fault.c | 7 + > include/linux/mm.h | 3 + > include/linux/uio.h | 5 + > lib/iov_iter.c | 132 +++++++++++++ > mm/filemap.c | 8 +- > mm/internal.h | 1 + > mm/memory-failure.c | 7 + > 13 files changed, 398 insertions(+), 1 deletion(-) > create mode 100644 arch/arm64/lib/copy_template_generic_read.S > > diff --git a/arch/arm64/include/asm/exception.h b/arch/arm64/include/asm/exception.h > index f938690c5ad6..559d86ad9e5d 100644 > --- a/arch/arm64/include/asm/exception.h > +++ b/arch/arm64/include/asm/exception.h > @@ -50,6 +50,7 @@ struct uce_kernel_recovery_info { > }; > > extern int copy_page_cow_sea_fallback(void); > +extern int copy_generic_read_sea_fallback(void); > #endif > > #endif /* __ASM_EXCEPTION_H */ > diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h > index 802a7d10ab82..b91fb7d6c18d 100644 > --- a/arch/arm64/include/asm/thread_info.h > +++ b/arch/arm64/include/asm/thread_info.h > @@ -93,6 +93,10 @@ void arch_release_task_struct(struct task_struct *tsk); > #define TIF_SVE_VL_INHERIT 24 /* Inherit sve_vl_onexec across exec */ > #define TIF_SSBD 25 /* Wants SSB mitigation */ > > +#ifdef CONFIG_UCE_KERNEL_RECOVERY > +#define TIF_UCE_KERNEL_RECOVERY 26 > +#endif > + > #define _TIF_SIGPENDING (1 << TIF_SIGPENDING) > #define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED) > #define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME) > @@ -110,6 +114,10 @@ void arch_release_task_struct(struct task_struct *tsk); > #define _TIF_SVE (1 << TIF_SVE) > #define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG) > > +#ifdef CONFIG_UCE_KERNEL_RECOVERY > +#define _TIF_UCE_KERNEL_RECOVERY (1 << TIF_UCE_KERNEL_RECOVERY) > +#endif > + > #define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_SIGPENDING | \ > _TIF_NOTIFY_RESUME | _TIF_FOREIGN_FPSTATE | \ > _TIF_UPROBE | _TIF_FSCHECK | _TIF_SEA_NOTIFY) > diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h > index 35482c9076db..52d3c8c64849 100644 > --- a/arch/arm64/include/asm/uaccess.h > +++ b/arch/arm64/include/asm/uaccess.h > @@ -407,6 +407,14 @@ extern unsigned long __must_check __arch_copy_from_user(void *to, const void __u > __arch_copy_from_user((to), __uaccess_mask_ptr(from), (n)); \ > }) > > +#ifdef CONFIG_UCE_KERNEL_RECOVERY > +extern unsigned long __must_check __arch_copy_to_user_generic_read(void __user *to, const void *from, unsigned long n); > +#define raw_copy_to_user_generic_read(to, from, n) \ > +({ \ > + __arch_copy_to_user_generic_read(__uaccess_mask_ptr(to), (from), (n)); \ > +}) > +#endif > + > extern unsigned long __must_check __arch_copy_to_user(void __user *to, const void *from, unsigned long n); > #define raw_copy_to_user(to, from, n) \ > ({ \ > diff --git a/arch/arm64/kernel/ras.c b/arch/arm64/kernel/ras.c > index 181e609e1cd4..b57041f9e6e7 100644 > --- a/arch/arm64/kernel/ras.c > +++ b/arch/arm64/kernel/ras.c > @@ -92,6 +92,13 @@ void sea_notify_process(void) > if (!si) > panic("Lost physical address for consumed uncorrectable error"); > > +#ifdef CONFIG_UCE_KERNEL_RECOVERY > + if (test_thread_flag(TIF_UCE_KERNEL_RECOVERY)) { > + flags |= MF_UCE_KERNEL_RECOVERY; > + clear_thread_flag(TIF_UCE_KERNEL_RECOVERY); > + } > +#endif > + > clear_thread_flag(TIF_SEA_NOTIFY); > do { > pfn = si->paddr >> PAGE_SHIFT; > diff --git a/arch/arm64/lib/copy_template_generic_read.S b/arch/arm64/lib/copy_template_generic_read.S > new file mode 100644 > index 000000000000..287193527260 > --- /dev/null > +++ b/arch/arm64/lib/copy_template_generic_read.S > @@ -0,0 +1,193 @@ > +/* > + * Copyright (C) 2013 ARM Ltd. > + * Copyright (C) 2013 Linaro. > + * > + * This code is based on glibc cortex strings work originally authored by Linaro > + * and re-licensed under GPLv2 for the Linux kernel. The original code can > + * be found @ > + * > + * http://bazaar.launchpad.net/~linaro-toolchain-dev/cortex-strings/trunk/ > + * files/head:/src/aarch64/ > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License version 2 as > + * published by the Free Software Foundation. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + * > + * You should have received a copy of the GNU General Public License > + * along with this program. If not, see <http://www.gnu.org/licenses/>. > + */ > + > + > +/* > + * Copy a buffer from src to dest (alignment handled by the hardware) > + * > + * Parameters: > + * x0 - dest > + * x1 - src > + * x2 - n > + * Returns: > + * x0 - dest > + */ > +dstin .req x0 > +src .req x1 > +count .req x2 > +tmp1 .req x3 > +tmp1w .req w3 > +tmp2 .req x4 > +tmp2w .req w4 > +dst .req x6 > + > +A_l .req x7 > +A_h .req x8 > +B_l .req x9 > +B_h .req x10 > +C_l .req x11 > +C_h .req x12 > +D_l .req x13 > +D_h .req x14 > + > + mov dst, dstin > + cmp count, #16 > + /*When memory length is less than 16, the accessed are not aligned.*/ > + b.lo .Ltiny15_gr > + > + neg tmp2, src > + ands tmp2, tmp2, #15/* Bytes to reach alignment. */ > + b.eq .LSrcAligned_gr > + sub count, count, tmp2 > + /* > + * Copy the leading memory data from src to dst in an increasing > + * address order.By this way,the risk of overwriting the source > + * memory data is eliminated when the distance between src and > + * dst is less than 16. The memory accesses here are alignment. > + */ > + tbz tmp2, #0, 1f > + ldrb1 tmp1w, src, #1 > + strb1 tmp1w, dst, #1 > +1: > + tbz tmp2, #1, 2f > + ldrh1 tmp1w, src, #2 > + strh1 tmp1w, dst, #2 > +2: > + tbz tmp2, #2, 3f > + ldr1 tmp1w, src, #4 > + str1 tmp1w, dst, #4 > +3: > + tbz tmp2, #3, .LSrcAligned_gr > + ldr1 tmp1, src, #8 > + str1 tmp1, dst, #8 > + > +.LSrcAligned_gr: > + cmp count, #64 > + b.ge .Lcpy_over64_gr > + /* > + * Deal with small copies quickly by dropping straight into the > + * exit block. > + */ > +.Ltail63_gr: > + /* > + * Copy up to 48 bytes of data. At this point we only need the > + * bottom 6 bits of count to be accurate. > + */ > + ands tmp1, count, #0x30 > + b.eq .Ltiny15_gr > + cmp tmp1w, #0x20 > + b.eq 1f > + b.lt 2f > + ldp1 A_l, A_h, src, #16 > + stp1 A_l, A_h, dst, #16 > +1: > + ldp1 A_l, A_h, src, #16 > + stp1 A_l, A_h, dst, #16 > +2: > + ldp1 A_l, A_h, src, #16 > + stp1 A_l, A_h, dst, #16 > +.Ltiny15_gr: > + /* > + * Prefer to break one ldp/stp into several load/store to access > + * memory in an increasing address order,rather than to load/store 16 > + * bytes from (src-16) to (dst-16) and to backward the src to aligned > + * address,which way is used in original cortex memcpy. If keeping > + * the original memcpy process here, memmove need to satisfy the > + * precondition that src address is at least 16 bytes bigger than dst > + * address,otherwise some source data will be overwritten when memove > + * call memcpy directly. To make memmove simpler and decouple the > + * memcpy's dependency on memmove, withdrew the original process. > + */ > + tbz count, #3, 1f > + ldr1 tmp1, src, #8 > + str1 tmp1, dst, #8 > +1: > + tbz count, #2, 2f > + ldr1 tmp1w, src, #4 > + str1 tmp1w, dst, #4 > +2: > + tbz count, #1, 3f > + ldrh1 tmp1w, src, #2 > + strh1 tmp1w, dst, #2 > +3: > + tbz count, #0, .Lexitfunc_gr > + ldrb1 tmp1w, src, #1 > + strb1 tmp1w, dst, #1 > + > + b .Lexitfunc_gr > + > +.Lcpy_over64_gr: > + subs count, count, #128 > + b.ge .Lcpy_body_large_gr > + /* > + * Less than 128 bytes to copy, so handle 64 here and then jump > + * to the tail. > + */ > + ldp1 A_l, A_h, src, #16 > + stp1 A_l, A_h, dst, #16 > + ldp1 B_l, B_h, src, #16 > + ldp1 C_l, C_h, src, #16 > + stp1 B_l, B_h, dst, #16 > + stp1 C_l, C_h, dst, #16 > + ldp1 D_l, D_h, src, #16 > + stp1 D_l, D_h, dst, #16 > + > + tst count, #0x3f > + b.ne .Ltail63_gr > + b .Lexitfunc_gr > + > + /* > + * Critical loop. Start at a new cache line boundary. Assuming > + * 64 bytes per line this ensures the entire loop is in one line. > + */ > + .p2align L1_CACHE_SHIFT > +.Lcpy_body_large_gr: > + /* pre-get 64 bytes data. */ > + ldp1 A_l, A_h, src, #16 > + ldp1 B_l, B_h, src, #16 > + ldp1 C_l, C_h, src, #16 > + ldp1 D_l, D_h, src, #16 > +1: > + /* > + * interlace the load of next 64 bytes data block with store of the last > + * loaded 64 bytes data. > + */ > + stp1 A_l, A_h, dst, #16 > + ldp1 A_l, A_h, src, #16 > + stp1 B_l, B_h, dst, #16 > + ldp1 B_l, B_h, src, #16 > + stp1 C_l, C_h, dst, #16 > + ldp1 C_l, C_h, src, #16 > + stp1 D_l, D_h, dst, #16 > + ldp1 D_l, D_h, src, #16 > + subs count, count, #64 > + b.ge 1b > + stp1 A_l, A_h, dst, #16 > + stp1 B_l, B_h, dst, #16 > + stp1 C_l, C_h, dst, #16 > + stp1 D_l, D_h, dst, #16 > + > + tst count, #0x3f > + b.ne .Ltail63_gr > +.Lexitfunc_gr: > diff --git a/arch/arm64/lib/copy_to_user.S b/arch/arm64/lib/copy_to_user.S > index 6b99b939c50f..769133236f4a 100644 > --- a/arch/arm64/lib/copy_to_user.S > +++ b/arch/arm64/lib/copy_to_user.S > @@ -71,6 +71,25 @@ ENTRY(__arch_copy_to_user) > ret > ENDPROC(__arch_copy_to_user) > > +#ifdef CONFIG_UCE_KERNEL_RECOVERY > +ENTRY(__arch_copy_to_user_generic_read) > + uaccess_enable_not_uao x3, x4, x5 > + add end, x0, x2 > +#include "copy_template_generic_read.S" > + uaccess_disable_not_uao x3, x4 > + > + mov x0, #0 > + ret > + > + .global copy_generic_read_sea_fallback > +copy_generic_read_sea_fallback: > + uaccess_disable_not_uao x3, x4 > + > + mov x0, #-1 > + ret > +ENDPROC(__arch_copy_to_user_generic_read) > +#endif > + > .section .fixup,"ax" > .align 2 > 9998: sub x0, end, dst // bytes not copied > diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c > index 039802b047af..08040fe73199 100644 > --- a/arch/arm64/mm/fault.c > +++ b/arch/arm64/mm/fault.c > @@ -662,6 +662,7 @@ int kernel_access_sea_recovery; > #define UCE_KER_REC_NUM ARRAY_SIZE(reco_info) > static struct uce_kernel_recovery_info reco_info[] = { > {copy_page_cow_sea_fallback, "copy_page_cow", (unsigned long)copy_page_cow, 0}, > + {copy_generic_read_sea_fallback, "__arch_copy_to_user_generic_read", (unsigned long)__arch_copy_to_user_generic_read, 0}, > }; > > static int __init kernel_access_sea_recovery_init(void) > @@ -708,6 +709,11 @@ int is_cow_kernel_recovery_enable(void) > return kernel_access_sea_recovery & 0x1; > } > > +int is_pagecache_reading_kernel_recovery_enable(void) > +{ > + return kernel_access_sea_recovery & 0x2; > +} > + > /* > * what is kernel recovery? > * If the process's private data is accessed in the kernel mode to trigger > @@ -827,6 +833,7 @@ static int do_sea(unsigned long addr, unsigned int esr, struct pt_regs *regs) > > idx = is_in_kernel_recovery(esr, regs); > if (idx >= 0 && idx < UCE_KER_REC_NUM) { > + set_thread_flag(TIF_UCE_KERNEL_RECOVERY); > clear_siginfo(&info); > info.si_signo = inf->sig; > info.si_errno = 0; > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 8b5f9b8fb1a3..5bd84fa48a44 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -2837,6 +2837,9 @@ enum mf_flags { > MF_ACTION_REQUIRED = 1 << 1, > MF_MUST_KILL = 1 << 2, > MF_SOFT_OFFLINE = 1 << 3, > +#ifdef CONFIG_UCE_KERNEL_RECOVERY > + MF_UCE_KERNEL_RECOVERY = 1 << 4 > +#endif > }; > extern int memory_failure(unsigned long pfn, int flags); > extern void memory_failure_queue(unsigned long pfn, int flags); > diff --git a/include/linux/uio.h b/include/linux/uio.h > index 422b1c01ee0d..13c48b13f21e 100644 > --- a/include/linux/uio.h > +++ b/include/linux/uio.h > @@ -97,6 +97,11 @@ bool _copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i); > size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i); > bool _copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i); > > +#ifdef CONFIG_UCE_KERNEL_RECOVERY > +size_t copy_page_to_iter_generic_read(struct page *page, size_t offset, > + size_t bytes, struct iov_iter *i); > +#endif > + > static __always_inline __must_check > size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) > { > diff --git a/lib/iov_iter.c b/lib/iov_iter.c > index dd8385a20325..66c0a4afbc74 100644 > --- a/lib/iov_iter.c > +++ b/lib/iov_iter.c > @@ -130,6 +130,17 @@ > } \ > } > > +#ifdef CONFIG_UCE_KERNEL_RECOVERY > +static int copyout_generic_read(void __user *to, const void *from, size_t n) > +{ > + if (access_ok(to, n)) { > + kasan_check_read(from, n); > + n = raw_copy_to_user_generic_read(to, from, n); > + } > + return n; > +} > +#endif > + > static int copyout(void __user *to, const void *from, size_t n) > { > if (access_ok(to, n)) { > @@ -148,6 +159,108 @@ static int copyin(void *to, const void __user *from, size_t n) > return n; > } > > +#ifdef CONFIG_UCE_KERNEL_RECOVERY > +static size_t copy_page_to_iter_iovec_generic_read(struct page *page, size_t offset, size_t bytes, > + struct iov_iter *i) > +{ > + size_t skip, copy, left, wanted; > + const struct iovec *iov; > + char __user *buf; > + void *kaddr, *from; > + > + if (unlikely(bytes > i->count)) > + bytes = i->count; > + > + if (unlikely(!bytes)) > + return 0; > + > + might_fault(); > + wanted = bytes; > + iov = i->iov; > + skip = i->iov_offset; > + buf = iov->iov_base + skip; > + copy = min(bytes, iov->iov_len - skip); > + > + if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_writeable(buf, copy)) { > + kaddr = kmap_atomic(page); > + from = kaddr + offset; > + > + /* first chunk, usually the only one */ > + left = copyout_generic_read(buf, from, copy); > + if (left == -1) { > + kunmap_atomic(kaddr); > + goto done; > + } > + copy -= left; > + skip += copy; > + from += copy; > + bytes -= copy; > + > + while (unlikely(!left && bytes)) { > + iov++; > + buf = iov->iov_base; > + copy = min(bytes, iov->iov_len); > + left = copyout_generic_read(buf, from, copy); > + if (left == -1) { > + kunmap_atomic(kaddr); > + goto done; > + } > + copy -= left; > + skip = copy; > + from += copy; > + bytes -= copy; > + } > + if (likely(!bytes)) { > + kunmap_atomic(kaddr); > + goto done; > + } > + offset = from - kaddr; > + buf += copy; > + kunmap_atomic(kaddr); > + copy = min(bytes, iov->iov_len - skip); > + } > + /* Too bad - revert to non-atomic kmap */ > + > + kaddr = kmap(page); > + from = kaddr + offset; > + left = copyout_generic_read(buf, from, copy); > + if (left == -1) { > + kunmap(page); > + goto done; > + } > + copy -= left; > + skip += copy; > + from += copy; > + bytes -= copy; > + while (unlikely(!left && bytes)) { > + iov++; > + buf = iov->iov_base; > + copy = min(bytes, iov->iov_len); > + left = copyout_generic_read(buf, from, copy); > + if (left == -1) { > + kunmap(page); > + goto done; > + } > + copy -= left; > + skip = copy; > + from += copy; > + bytes -= copy; > + } > + kunmap(page); > + > +done: > + if (skip == iov->iov_len) { > + iov++; > + skip = 0; > + } > + i->count -= wanted - bytes; > + i->nr_segs -= iov - i->iov; > + i->iov = iov; > + i->iov_offset = skip; > + return wanted - bytes; > +} > +#endif > + > static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes, > struct iov_iter *i) > { > @@ -839,6 +952,25 @@ static inline bool page_copy_sane(struct page *page, size_t offset, size_t n) > return false; > } > > +#ifdef CONFIG_UCE_KERNEL_RECOVERY > +size_t copy_page_to_iter_generic_read(struct page *page, size_t offset, size_t bytes, > + struct iov_iter *i) > +{ > + if (unlikely(!page_copy_sane(page, offset, bytes))) > + return 0; > + if (i->type & (ITER_BVEC|ITER_KVEC)) { > + void *kaddr = kmap_atomic(page); > + size_t wanted = copy_to_iter(kaddr + offset, bytes, i); > + kunmap_atomic(kaddr); > + return wanted; > + } else if (likely(!(i->type & ITER_PIPE))) > + return copy_page_to_iter_iovec_generic_read(page, offset, bytes, i); > + else > + return copy_page_to_iter_pipe(page, offset, bytes, i); > +} > +EXPORT_SYMBOL(copy_page_to_iter_generic_read); > +#endif > + > size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, > struct iov_iter *i) > { > diff --git a/mm/filemap.c b/mm/filemap.c > index 6a212192e1b7..5c33c40e8019 100644 > --- a/mm/filemap.c > +++ b/mm/filemap.c > @@ -2290,8 +2290,14 @@ static ssize_t generic_file_buffered_read(struct kiocb *iocb, > * Ok, we have the page, and it's up-to-date, so > * now we can copy it to user space... > */ > - > +#ifdef CONFIG_UCE_KERNEL_RECOVERY > + if (is_pagecache_reading_kernel_recovery_enable()) > + ret = copy_page_to_iter_generic_read(page, offset, nr, iter); > + else > + ret = copy_page_to_iter(page, offset, nr, iter); > +#else > ret = copy_page_to_iter(page, offset, nr, iter); > +#endif > offset += ret; > index += offset >> PAGE_SHIFT; > offset &= ~PAGE_MASK; > diff --git a/mm/internal.h b/mm/internal.h > index b6d3b3660782..3bb7ca86e84e 100644 > --- a/mm/internal.h > +++ b/mm/internal.h > @@ -591,6 +591,7 @@ extern struct page *alloc_new_node_page(struct page *page, unsigned long node); > > #ifdef CONFIG_UCE_KERNEL_RECOVERY > extern int is_cow_kernel_recovery_enable(void); > +extern int is_pagecache_reading_kernel_recovery_enable(void); > #endif > > #endif /* __MM_INTERNAL_H */ > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > index 145262227bb0..1316e86e0a16 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -1395,6 +1395,13 @@ int memory_failure(unsigned long pfn, int flags) > if (!PageTransTail(p) && !PageLRU(p) && !PageWriteback(p)) > goto identify_page_state; > > +#ifdef CONFIG_UCE_KERNEL_RECOVERY > + if ((flags & MF_UCE_KERNEL_RECOVERY) && PageWriteback(p)) { > + panic("UCE in memory failure while Page writeback, panic on page %lx, flags %x", > + pfn, flags); > + } > +#endif > + > /* > * It's very difficult to mess with pages currently under IO > * and in many cases impossible, so we just avoid it here. >

1 0

Re: [kernel-4.19 1/2] uce: cow scenario support kernel recovery
by Xie XiuQi 11 Aug '21

11 Aug '21

Hi, Thanks for your patches. There are trinval typo, otherwice, looks good to me. Reviewed-by: Xie XiuQi <xiexiuqi(a)huawei.com> On 2021/8/11 11:37, Tong Tiangen wrote: > hulk inclusion > category: feature > bugzilla: https://gitee.com/openeuler/kernel/issues/I44R9D > CVE: NA > > --------------------------- > > During kernel COW processing, the kernel triggers a RAS exception when reading > pages. In this solution, we identify this scenario in the kernel do_sea processing > process, send SIGBUS signals to the process that triggers COW and isolate memory > pages, preventing kernel panic. > > At the same time, we use both cmdline(uce_kernel_recovery) and proc(/proc/sys/ > kernel/uce_kernel_recovery) to control this feature on/off. > > We use customized functions to distinguish scenarios that need kernel recovery, > specifically copy_page_cow(). When hardware error occurs in this function, we > killing the process that triggers the hardware error to replace the kernel die. > > Signed-off-by: Tong Tiangen <tongtiangen(a)huawei.com> > Signed-off-by: Chen Huang <chenhuang5(a)huawei.com> > --- > arch/arm64/Kconfig | 10 ++ > arch/arm64/include/asm/exception.h | 11 +++ > arch/arm64/include/asm/page.h | 8 ++ > arch/arm64/lib/copy_page.S | 78 +++++++++++++++ > arch/arm64/mm/copypage.c | 14 +++ > arch/arm64/mm/fault.c | 153 +++++++++++++++++++++++++++++ > include/linux/highmem.h | 17 ++++ > include/linux/kernel.h | 4 + > kernel/sysctl.c | 13 +++ > mm/internal.h | 5 + > mm/memory.c | 8 ++ > 11 files changed, 321 insertions(+) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 99905ee64625..e968df599e31 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -1755,6 +1755,16 @@ config ARCH_HIBERNATION_HEADER > config ARCH_SUSPEND_POSSIBLE > def_bool y > > +config UCE_KERNEL_RECOVERY > + bool "uce kernel recovery from special scenario" > + def_bool y > + depends on ARM64_ERR_RECOV > + help > + With ARM v8.2 RAS Extension, SEA are usually triggered when memory errors > + are consumed. In some cases, if the error address is in a user page there > + is a chance to recover. Such as error occurs in COW and pagecache reading > + cenario, we can isolate this page and killing process instead of die. s/cenario/scenario/ > + > endmenu > > menu "CPU Power Management" > diff --git a/arch/arm64/include/asm/exception.h b/arch/arm64/include/asm/exception.h > index bc30429d8e91..f938690c5ad6 100644 > --- a/arch/arm64/include/asm/exception.h > +++ b/arch/arm64/include/asm/exception.h > @@ -41,4 +41,15 @@ static inline u32 disr_to_esr(u64 disr) > return esr; > } > > +#ifdef CONFIG_UCE_KERNEL_RECOVERY > +struct uce_kernel_recovery_info { > + int (*fn)(void); > + const char *name; > + unsigned long addr; > + unsigned long size; > +}; > + > +extern int copy_page_cow_sea_fallback(void); > +#endif > + > #endif /* __ASM_EXCEPTION_H */ > diff --git a/arch/arm64/include/asm/page.h b/arch/arm64/include/asm/page.h > index 60d02c81a3a2..725bff5bc0ad 100644 > --- a/arch/arm64/include/asm/page.h > +++ b/arch/arm64/include/asm/page.h > @@ -35,6 +35,14 @@ extern void clear_page(void *to); > #define clear_user_page(addr,vaddr,pg) __cpu_clear_user_page(addr, vaddr) > #define copy_user_page(to,from,vaddr,pg) __cpu_copy_user_page(to, from, vaddr) > > +#ifdef CONFIG_UCE_KERNEL_RECOVERY > +extern int copy_page_cow(void *to, const void *from); > +extern int __cpu_copy_user_page_cow(void *to, const void *from, > + unsigned long user); > +#define copy_user_page_cow(to, from, vaddr, pg) \ > + __cpu_copy_user_page_cow(to, from, vaddr) > +#endif > + > typedef struct page *pgtable_t; > > #ifdef CONFIG_HAVE_ARCH_PFN_VALID > diff --git a/arch/arm64/lib/copy_page.S b/arch/arm64/lib/copy_page.S > index 076c43715e64..649cf4eb96bf 100644 > --- a/arch/arm64/lib/copy_page.S > +++ b/arch/arm64/lib/copy_page.S > @@ -87,3 +87,81 @@ alternative_else_nop_endif > > ret > ENDPROC(copy_page) > + > +#ifdef CONFIG_UCE_KERNEL_RECOVERY > +#The difference between copy_page_cow and copy_page: > +# 1) copy_page_cow adds the recovery path of sea fault(copy_page_cow_sea_fallback). > +# 2) copy_page_cow with return value: 0 - copy success 1 - copy fail. > +/* > + * COW copy a page from src to dest (both are page aligned) > + * > + * Parameters: > + * x0 - dest > + * x1 - src > + */ > +ENTRY(copy_page_cow) > +alternative_if ARM64_HAS_NO_HW_PREFETCH > + // Prefetch three cache lines ahead. > + prfm pldl1strm, [x1, #128] > + prfm pldl1strm, [x1, #256] > + prfm pldl1strm, [x1, #384] > +alternative_else_nop_endif > + > + ldp x2, x3, [x1] > + ldp x4, x5, [x1, #16] > + ldp x6, x7, [x1, #32] > + ldp x8, x9, [x1, #48] > + ldp x10, x11, [x1, #64] > + ldp x12, x13, [x1, #80] > + ldp x14, x15, [x1, #96] > + ldp x16, x17, [x1, #112] > + > + mov x18, #(PAGE_SIZE - 128) > + add x1, x1, #128 > +1: > + subs x18, x18, #128 > + > +alternative_if ARM64_HAS_NO_HW_PREFETCH > + prfm pldl1strm, [x1, #384] > +alternative_else_nop_endif > + > + stnp x2, x3, [x0] > + ldp x2, x3, [x1] > + stnp x4, x5, [x0, #16] > + ldp x4, x5, [x1, #16] > + stnp x6, x7, [x0, #32] > + ldp x6, x7, [x1, #32] > + stnp x8, x9, [x0, #48] > + ldp x8, x9, [x1, #48] > + stnp x10, x11, [x0, #64] > + ldp x10, x11, [x1, #64] > + stnp x12, x13, [x0, #80] > + ldp x12, x13, [x1, #80] > + stnp x14, x15, [x0, #96] > + ldp x14, x15, [x1, #96] > + stnp x16, x17, [x0, #112] > + ldp x16, x17, [x1, #112] > + > + add x0, x0, #128 > + add x1, x1, #128 > + > + b.gt 1b > + > + stnp x2, x3, [x0] > + stnp x4, x5, [x0, #16] > + stnp x6, x7, [x0, #32] > + stnp x8, x9, [x0, #48] > + stnp x10, x11, [x0, #64] > + stnp x12, x13, [x0, #80] > + stnp x14, x15, [x0, #96] > + stnp x16, x17, [x0, #112] > + > + mov x0, #0 > + ret > + > + .global copy_page_cow_sea_fallback > +copy_page_cow_sea_fallback: > + mov x0, #1 > + ret > +ENDPROC(copy_page_cow) > +#endif > diff --git a/arch/arm64/mm/copypage.c b/arch/arm64/mm/copypage.c > index 22e4cb4d6f53..506d166d1dec 100644 > --- a/arch/arm64/mm/copypage.c > +++ b/arch/arm64/mm/copypage.c > @@ -30,6 +30,20 @@ void __cpu_copy_user_page(void *kto, const void *kfrom, unsigned long vaddr) > } > EXPORT_SYMBOL_GPL(__cpu_copy_user_page); > > +#ifdef CONFIG_UCE_KERNEL_RECOVERY > +int __cpu_copy_user_page_cow(void *kto, const void *kfrom, unsigned long vaddr) > +{ > + int ret; > + > + struct page *page = virt_to_page(kto); > + ret = copy_page_cow(kto, kfrom); > + flush_dcache_page(page); > + > + return ret; > +} > +EXPORT_SYMBOL_GPL(__cpu_copy_user_page_cow); > +#endif > + > void __cpu_clear_user_page(void *kaddr, unsigned long vaddr) > { > clear_page(kaddr); > diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c > index 6cd448d9835c..039802b047af 100644 > --- a/arch/arm64/mm/fault.c > +++ b/arch/arm64/mm/fault.c > @@ -656,6 +656,126 @@ static int do_bad(unsigned long addr, unsigned int esr, struct pt_regs *regs) > return 1; /* "fault" */ > } > > +#ifdef CONFIG_UCE_KERNEL_RECOVERY > +int kernel_access_sea_recovery; > + > +#define UCE_KER_REC_NUM ARRAY_SIZE(reco_info) > +static struct uce_kernel_recovery_info reco_info[] = { > + {copy_page_cow_sea_fallback, "copy_page_cow", (unsigned long)copy_page_cow, 0}, > +}; > + > +static int __init kernel_access_sea_recovery_init(void) > +{ > + unsigned long addr, size, offset; > + unsigned int i; > + > + for (i = 0; i < UCE_KER_REC_NUM; i++) { > + addr = reco_info[i].addr; > + if (!kallsyms_lookup_size_offset(addr, &size, &offset)) { > + pr_info("UCE: symbol %s lookup addr fail.\n", > + reco_info[i].name); > + size = 0; > + } > + > + reco_info[i].size = size; > + } > + > + return 1; > +} > +fs_initcall(kernel_access_sea_recovery_init); > + > +static int __init enable_kernel_access_sea_recovery(char *str) > +{ > + int max = (1 << UCE_KER_REC_NUM) - 1; > + int val; > + > + if (kstrtoint(str, 0, &val)) > + return -EINVAL; > + > + if (val < 0 || val > max) { > + pr_info("UCE: invalid uce_kernel_recovery value %d", val); > + return -EINVAL; > + } > + > + kernel_access_sea_recovery = val; > + > + return 1; > +} > +__setup("uce_kernel_recovery=", enable_kernel_access_sea_recovery); > + > +int is_cow_kernel_recovery_enable(void) > +{ > + return kernel_access_sea_recovery & 0x1; > +} > + > +/* > + * what is kernel recovery? > + * If the process's private data is accessed in the kernel mode to trigger > + * special sea fault, it can controlled by killing the process and isolating > + * the failure pages instead of die. > + */ > +static int is_in_kernel_recovery(unsigned int esr, struct pt_regs *regs) > +{ > + /* > + * target insn: ldp-pre, ldp-post, ldp-offset, > + * ldr-64bit-pre/pose, ldr-32bit-pre/post, ldrb-pre/post, ldrh-pre/post > + */ > + u32 target_insn[] = {0xa8c, 0xa9c, 0xa94, 0xf84, 0x784, 0x384, 0xb84}; > + void *pc = (void *)instruction_pointer(regs); > + struct uce_kernel_recovery_info *info; > + bool insn_match = false; > + u32 insn; > + int i; > + > + pr_emerg("UCE: %s-%d, kernel recovery: 0x%x, esr: 0x%08x -- %s, %pS\n", > + current->comm, current->pid, kernel_access_sea_recovery, esr, > + esr_get_class_string(esr), pc); > + > + if (aarch64_insn_read((void *)pc, &insn)) { > + pr_emerg("UCE: insn read fail.\n"); > + return -EFAULT; > + } > + > + /* > + * We process special ESR: > + * EC : 0b100101 Data Abort taken without a change in Exception level. > + * DFSC : 0b010000 Synchronous External abort, not on translation table > + * walk or hardware update of translation table. > + * eg: 0x96000610 > + */ > + if (ESR_ELx_EC(esr) != ESR_ELx_EC_DABT_CUR || > + (esr & ESR_ELx_FSC) != ESR_ELx_FSC_EXTABT) { > + pr_emerg("UCE: esr not match.\n"); > + return -EINVAL; > + } > + > + insn = (insn >> 20) & 0xffc; > + for (i = 0; i < ARRAY_SIZE(target_insn); i++) { > + if (insn == target_insn[i]) { > + insn_match = true; > + break; > + } > + } > + > + if (!insn_match) { > + pr_emerg("UCE: insn 0x%x is not match.\n", insn); > + return -EINVAL; > + } > + > + for (i = 0; i < UCE_KER_REC_NUM; i++) { > + info = &reco_info[i]; > + if (info->fn && regs->pc >= info->addr && > + regs->pc < (info->addr + info->size)) { > + pr_emerg("UCE: total match %s success.\n", info->name); > + return i; > + } > + } > + > + pr_emerg("UCE: symbol is not match.\n"); > + return -EINVAL; > +} > +#endif > + > static int do_sea(unsigned long addr, unsigned int esr, struct pt_regs *regs) > { > struct siginfo info; > @@ -693,8 +813,41 @@ static int do_sea(unsigned long addr, unsigned int esr, struct pt_regs *regs) > > arm64_notify_die(inf->name, regs, &info, esr); > } else { > +#ifdef CONFIG_UCE_KERNEL_RECOVERY > + int idx; > + > + if (!current->mm || !kernel_access_sea_recovery) { > + pr_emerg("UCE: kernel recovery %d, %s-%d is %s-thread.\n", > + kernel_access_sea_recovery, > + current->comm, current->pid, > + (current->mm) ? "user" : "kernel"); > + die("Uncorrected hardware memory error in kernel-access\n", > + regs, esr); > + } > + > + idx = is_in_kernel_recovery(esr, regs); > + if (idx >= 0 && idx < UCE_KER_REC_NUM) { > + clear_siginfo(&info); > + info.si_signo = inf->sig; > + info.si_errno = 0; > + info.si_code = inf->code; > + info.si_addr = NULL; > + > + current->thread.fault_address = regs->pc; > + current->thread.fault_code = esr; > + regs->pc = (unsigned long)reco_info[idx].fn; > + arm64_force_sig_info(&info, > + "Uncorrected hardware memory use with kernel recovery in kernel-access\n", > + current); > + } else { > + die("Uncorrected hardware memory error (kernel recovery on but not match idx) in kernel-access\n", > + regs, esr); Do you mean "kernel recovery is enabled, but not match the idx" ? This path is the common case if in-kernel access uce. So we could just use the default message, or "Uncorrected hardware memory error without kernel recovery in kernel-access" ? > + } > + > +#else > die("Uncorrected hardware memory error in kernel-access\n", > regs, esr); > +#endif > } > > return 0; > diff --git a/include/linux/highmem.h b/include/linux/highmem.h > index 0690679832d4..1fed918bb1e5 100644 > --- a/include/linux/highmem.h > +++ b/include/linux/highmem.h > @@ -235,6 +235,23 @@ static inline void copy_user_highpage(struct page *to, struct page *from, > kunmap_atomic(vfrom); > } > > +#ifdef CONFIG_UCE_KERNEL_RECOVERY > +static inline int copy_user_highpage_cow(struct page *to, struct page *from, > + unsigned long vaddr, struct vm_area_struct *vma) > +{ > + char *vfrom, *vto; > + int ret; > + > + vfrom = kmap_atomic(from); > + vto = kmap_atomic(to); > + ret = copy_user_page_cow(vto, vfrom, vaddr, to); > + kunmap_atomic(vto); > + kunmap_atomic(vfrom); > + > + return ret; > +} > +#endif > + > #endif > > #ifndef __HAVE_ARCH_COPY_HIGHPAGE > diff --git a/include/linux/kernel.h b/include/linux/kernel.h > index f24fd248b3ac..122f77b8b0ea 100644 > --- a/include/linux/kernel.h > +++ b/include/linux/kernel.h > @@ -531,6 +531,10 @@ extern int sysctl_panic_on_stackoverflow; > > extern bool crash_kexec_post_notifiers; > > +#ifdef CONFIG_UCE_KERNEL_RECOVERY > +extern int kernel_access_sea_recovery; > +#endif > + > /* > * panic_cpu is used for synchronizing panic() and crash_kexec() execution. It > * holds a CPU number which is executing panic() currently. A value of > diff --git a/kernel/sysctl.c b/kernel/sysctl.c > index 116fe8a13236..53ddcd74b5c3 100644 > --- a/kernel/sysctl.c > +++ b/kernel/sysctl.c > @@ -127,6 +127,7 @@ static int __maybe_unused neg_one = -1; > static int zero; > static int __maybe_unused one = 1; > static int __maybe_unused two = 2; > +static int __maybe_unused three = 3; > static int __maybe_unused four = 4; > static unsigned long zero_ul; > static unsigned long one_ul = 1; > @@ -1254,6 +1255,18 @@ static struct ctl_table kern_table[] = { > .extra1 = &zero, > .extra2 = &one, > }, > +#if defined(CONFIG_UCE_KERNEL_RECOVERY) > + { > + .procname = "uce_kernel_recovery", > + .data = &kernel_access_sea_recovery, > + .maxlen = sizeof(kernel_access_sea_recovery), > + .mode = 0644, > + .proc_handler = proc_dointvec_minmax, > + .extra1 = &zero, > + .extra2 = &three, > + }, > + > +#endif > { } > }; > > diff --git a/mm/internal.h b/mm/internal.h > index bfa97c43a3fc..b6d3b3660782 100644 > --- a/mm/internal.h > +++ b/mm/internal.h > @@ -588,4 +588,9 @@ static inline bool is_migrate_highatomic_page(struct page *page) > > void setup_zone_pageset(struct zone *zone); > extern struct page *alloc_new_node_page(struct page *page, unsigned long node); > + > +#ifdef CONFIG_UCE_KERNEL_RECOVERY > +extern int is_cow_kernel_recovery_enable(void); > +#endif > + > #endif /* __MM_INTERNAL_H */ > diff --git a/mm/memory.c b/mm/memory.c > index d9f4e7dd17a6..174b0baf197e 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -2212,7 +2212,15 @@ static inline bool cow_user_page(struct page *dst, struct page *src, > debug_dma_assert_idle(src); > > if (likely(src)) { > +#ifdef CONFIG_UCE_KERNEL_RECOVERY > + if (is_cow_kernel_recovery_enable()) { > + if (copy_user_highpage_cow(dst, src, addr, vma)) > + return false; > + } else > + copy_user_highpage(dst, src, addr, vma); > +#else > copy_user_highpage(dst, src, addr, vma); > +#endif > return true; > } > >

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[PATCH OLK-5.10] USB: fix some clerical mistakes
by LeoLiuoc 11 Aug '21

11 Aug '21

Fix some clerical mistakes in previous patch<71fb26516dc8bb3050fa96a4290db64fc9d6c54b>. Signed-off-by: LeoLiu-oc <LeoLiu-oc(a)zhaoxin.com> --- drivers/usb/core/hcd-pci.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c index 000ee7a6731f..bbf9bd2d4b08 100644 --- a/drivers/usb/core/hcd-pci.c +++ b/drivers/usb/core/hcd-pci.c @@ -67,8 +67,8 @@ static void for_each_companion(struct pci_dev *pdev, struct usb_hcd *hcd, continue; if (strncmp(drv->name, "uhci_hcd", sizeof("uhci_hcd") - 1) && - strncmp(drv->name, "ooci_hcd", sizeof("uhci_hcd") - 1) && - strncmp(drv->name, "ehci_hcd", sizeof("uhci_hcd") - 1)) + strncmp(drv->name, "ohci-pci", sizeof("ohci-pci") - 1) && + strncmp(drv->name, "ehci-pci", sizeof("ehci-pci") - 1)) continue; /* -- 2.20.1

2 1

[PATCH kernel-4.19] USB: fix some clerical mistakes
by LeoLiuoc 11 Aug '21

11 Aug '21

Fix some clerical mistakes in previous patch<4d6c910e0825f397ea3b7cdfd639bdc12d878d27> Signed-off-by: LeoLiu-oc <LeoLiu-oc(a)zhaoxin.com> --- drivers/usb/core/hcd-pci.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c index c3cddaab708d..d4234f81b791 100644 --- a/drivers/usb/core/hcd-pci.c +++ b/drivers/usb/core/hcd-pci.c @@ -67,8 +67,8 @@ static void for_each_companion(struct pci_dev *pdev, struct usb_hcd *hcd, continue; if (strncmp(drv->name, "uhci_hcd", sizeof("uhci_hcd") - 1) && - strncmp(drv->name, "ooci_hcd", sizeof("uhci_hcd") - 1) && - strncmp(drv->name, "ehci_hcd", sizeof("uhci_hcd") - 1)) + strncmp(drv->name, "ohci-pci", sizeof("ohci-pci") - 1) && + strncmp(drv->name, "ehci-pci", sizeof("ehci-pci") - 1)) continue; /* -- 2.20.1

2 1

[PATCH kernel-4.19] livepatch/x86: Ignore return code of save_stack_trace_tsk_reliable()
by Yang Yingliang 10 Aug '21

10 Aug '21

From: Wang ShaoBo <bobo.shaobowang(a)huawei.com> hulk inclusion category: bugfix bugzilla: 175666 CVE: NA --------------------------- Checking return code of save_stack_trace_tsk_reliable() can be relaxed for safety validation when appling livepatch, so we ignore it's return code in klp_check_stack(). Signed-off-by: Wang ShaoBo <bobo.shaobowang(a)huawei.com> Reviewed-by: Jian Cheng <cj.chengjian(a)huawei.com> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> --- arch/x86/kernel/livepatch.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/arch/x86/kernel/livepatch.c b/arch/x86/kernel/livepatch.c index e927624d5016f..4d5599e443884 100644 --- a/arch/x86/kernel/livepatch.c +++ b/arch/x86/kernel/livepatch.c @@ -210,9 +210,8 @@ static int klp_check_stack(struct task_struct *task, ret = save_stack_trace_tsk_reliable(task, &trace); WARN_ON_ONCE(ret == -ENOSYS); if (ret) { - pr_info("%s: %s:%d has an unreliable stack\n", + pr_debug("%s: %s:%d has an unreliable stack\n", __func__, task->comm, task->pid); - return ret; } klp_for_each_object(patch, obj) { -- 2.25.1

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