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[PATCH OLK-5.10] x86/efi: defer freeing of boot services memory
by Jinjie Ruan 28 Mar '26

28 Mar '26

From: "Mike Rapoport (Microsoft)" <rppt(a)kernel.org> stable inclusion from stable-v6.6.130 commit 6a25e25279282c5c8ade554c04c6ab9dc7902c64 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/13929 CVE: CVE-2026-23352 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- commit a4b0bf6a40f3c107c67a24fbc614510ef5719980 upstream. efi_free_boot_services() frees memory occupied by EFI_BOOT_SERVICES_CODE and EFI_BOOT_SERVICES_DATA using memblock_free_late(). There are two issue with that: memblock_free_late() should be used for memory allocated with memblock_alloc() while the memory reserved with memblock_reserve() should be freed with free_reserved_area(). More acutely, with CONFIG_DEFERRED_STRUCT_PAGE_INIT=y efi_free_boot_services() is called before deferred initialization of the memory map is complete. Benjamin Herrenschmidt reports that this causes a leak of ~140MB of RAM on EC2 t3a.nano instances which only have 512MB or RAM. If the freed memory resides in the areas that memory map for them is still uninitialized, they won't be actually freed because memblock_free_late() calls memblock_free_pages() and the latter skips uninitialized pages. Using free_reserved_area() at this point is also problematic because __free_page() accesses the buddy of the freed page and that again might end up in uninitialized part of the memory map. Delaying the entire efi_free_boot_services() could be problematic because in addition to freeing boot services memory it updates efi.memmap without any synchronization and that's undesirable late in boot when there is concurrency. More robust approach is to only defer freeing of the EFI boot services memory. Split efi_free_boot_services() in two. First efi_unmap_boot_services() collects ranges that should be freed into an array then efi_free_boot_services() later frees them after deferred init is complete. Link: https://lore.kernel.org/all/ec2aaef14783869b3be6e3c253b2dcbf67dbc12a.camel@… Fixes: 916f676f8dc0 ("x86, efi: Retain boot service code until after switching to virtual mode") Cc: <stable(a)vger.kernel.org> Signed-off-by: Mike Rapoport (Microsoft) <rppt(a)kernel.org> Reviewed-by: Benjamin Herrenschmidt <benh(a)kernel.crashing.org> Signed-off-by: Ard Biesheuvel <ardb(a)kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Conflicts: arch/x86/include/asm/efi.h arch/x86/platform/efi/quirks.c [ context conflict. ] Signed-off-by: Jinjie Ruan <ruanjinjie(a)huawei.com> --- arch/x86/include/asm/efi.h | 2 +- arch/x86/platform/efi/efi.c | 2 +- arch/x86/platform/efi/quirks.c | 55 +++++++++++++++++++++++++++-- drivers/firmware/efi/mokvar-table.c | 2 +- 4 files changed, 55 insertions(+), 6 deletions(-) diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h index 2de20f6a765b..fb1c8fded78b 100644 --- a/arch/x86/include/asm/efi.h +++ b/arch/x86/include/asm/efi.h @@ -149,7 +149,7 @@ extern int __init efi_reuse_config(u64 tables, int nr_tables); extern void efi_delete_dummy_variable(void); extern void efi_switch_mm(struct mm_struct *mm); extern void efi_recover_from_page_fault(unsigned long phys_addr); -extern void efi_free_boot_services(void); +extern void efi_unmap_boot_services(void); /* kexec external ABI */ struct efi_setup_data { diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index 91f8edd50dd7..9f18c5d2a812 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -793,7 +793,7 @@ static void __init __efi_enter_virtual_mode(void) } efi_check_for_embedded_firmwares(); - efi_free_boot_services(); + efi_unmap_boot_services(); if (!efi_is_mixed()) efi_native_runtime_setup(); diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c index c1eec019dcee..a152d5762400 100644 --- a/arch/x86/platform/efi/quirks.c +++ b/arch/x86/platform/efi/quirks.c @@ -333,7 +333,7 @@ void __init efi_reserve_boot_services(void) /* * Because the following memblock_reserve() is paired - * with memblock_free_late() for this region in + * with free_reserved_area() for this region in * efi_free_boot_services(), we must be extremely * careful not to reserve, and subsequently free, * critical regions of memory (like the kernel image) or @@ -396,17 +396,33 @@ static void __init efi_unmap_pages(efi_memory_desc_t *md) pr_err("Failed to unmap VA mapping for 0x%llx\n", va); } -void __init efi_free_boot_services(void) +struct efi_freeable_range { + u64 start; + u64 end; +}; + +static struct efi_freeable_range *ranges_to_free; + +void __init efi_unmap_boot_services(void) { struct efi_memory_map_data data = { 0 }; efi_memory_desc_t *md; int num_entries = 0; + int idx = 0; + size_t sz; void *new, *new_md; /* Keep all regions for /sys/kernel/debug/efi */ if (efi_enabled(EFI_DBG)) return; + sz = sizeof(*ranges_to_free) * efi.memmap.nr_map + 1; + ranges_to_free = kzalloc(sz, GFP_KERNEL); + if (!ranges_to_free) { + pr_err("Failed to allocate storage for freeable EFI regions\n"); + return; + } + for_each_efi_memory_desc(md) { unsigned long long start = md->phys_addr; unsigned long long size = md->num_pages << EFI_PAGE_SHIFT; @@ -451,7 +467,15 @@ void __init efi_free_boot_services(void) size -= rm_size; } - memblock_free_late(start, size); + /* + * With CONFIG_DEFERRED_STRUCT_PAGE_INIT parts of the memory + * map are still not initialized and we can't reliably free + * memory here. + * Queue the ranges to free at a later point. + */ + ranges_to_free[idx].start = start; + ranges_to_free[idx].end = start + size; + idx++; } if (!num_entries) @@ -492,6 +516,31 @@ void __init efi_free_boot_services(void) } } +static int __init efi_free_boot_services(void) +{ + struct efi_freeable_range *range = ranges_to_free; + unsigned long freed = 0; + + if (!ranges_to_free) + return 0; + + while (range->start) { + void *start = phys_to_virt(range->start); + void *end = phys_to_virt(range->end); + + free_reserved_area(start, end, -1, NULL); + freed += (end - start); + range++; + } + kfree(ranges_to_free); + + if (freed) + pr_info("Freeing EFI boot services memory: %ldK\n", freed / SZ_1K); + + return 0; +} +arch_initcall(efi_free_boot_services); + /* * A number of config table entries get remapped to virtual addresses * after entering EFI virtual mode. However, the kexec kernel requires diff --git a/drivers/firmware/efi/mokvar-table.c b/drivers/firmware/efi/mokvar-table.c index 38722d2009e2..4a5c2f823788 100644 --- a/drivers/firmware/efi/mokvar-table.c +++ b/drivers/firmware/efi/mokvar-table.c @@ -85,7 +85,7 @@ static struct kobject *mokvar_kobj; * as an alternative to ordinary EFI variables, due to platform-dependent * limitations. The memory occupied by this table is marked as reserved. * - * This routine must be called before efi_free_boot_services() in order + * This routine must be called before efi_unmap_boot_services() in order * to guarantee that it can mark the table as reserved. * * Implicit inputs: -- 2.34.1

2 1

[PATCH OLK-6.6] x86/efi: defer freeing of boot services memory
by Jinjie Ruan 28 Mar '26

28 Mar '26

From: "Mike Rapoport (Microsoft)" <rppt(a)kernel.org> stable inclusion from stable-v6.6.130 commit 6a25e25279282c5c8ade554c04c6ab9dc7902c64 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/13929 CVE: CVE-2026-23352 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- commit a4b0bf6a40f3c107c67a24fbc614510ef5719980 upstream. efi_free_boot_services() frees memory occupied by EFI_BOOT_SERVICES_CODE and EFI_BOOT_SERVICES_DATA using memblock_free_late(). There are two issue with that: memblock_free_late() should be used for memory allocated with memblock_alloc() while the memory reserved with memblock_reserve() should be freed with free_reserved_area(). More acutely, with CONFIG_DEFERRED_STRUCT_PAGE_INIT=y efi_free_boot_services() is called before deferred initialization of the memory map is complete. Benjamin Herrenschmidt reports that this causes a leak of ~140MB of RAM on EC2 t3a.nano instances which only have 512MB or RAM. If the freed memory resides in the areas that memory map for them is still uninitialized, they won't be actually freed because memblock_free_late() calls memblock_free_pages() and the latter skips uninitialized pages. Using free_reserved_area() at this point is also problematic because __free_page() accesses the buddy of the freed page and that again might end up in uninitialized part of the memory map. Delaying the entire efi_free_boot_services() could be problematic because in addition to freeing boot services memory it updates efi.memmap without any synchronization and that's undesirable late in boot when there is concurrency. More robust approach is to only defer freeing of the EFI boot services memory. Split efi_free_boot_services() in two. First efi_unmap_boot_services() collects ranges that should be freed into an array then efi_free_boot_services() later frees them after deferred init is complete. Link: https://lore.kernel.org/all/ec2aaef14783869b3be6e3c253b2dcbf67dbc12a.camel@… Fixes: 916f676f8dc0 ("x86, efi: Retain boot service code until after switching to virtual mode") Cc: <stable(a)vger.kernel.org> Signed-off-by: Mike Rapoport (Microsoft) <rppt(a)kernel.org> Reviewed-by: Benjamin Herrenschmidt <benh(a)kernel.crashing.org> Signed-off-by: Ard Biesheuvel <ardb(a)kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Jinjie Ruan <ruanjinjie(a)huawei.com> --- arch/x86/include/asm/efi.h | 2 +- arch/x86/platform/efi/efi.c | 2 +- arch/x86/platform/efi/quirks.c | 55 +++++++++++++++++++++++++++-- drivers/firmware/efi/mokvar-table.c | 2 +- 4 files changed, 55 insertions(+), 6 deletions(-) diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h index a050d329e34b..aaf1e71b067a 100644 --- a/arch/x86/include/asm/efi.h +++ b/arch/x86/include/asm/efi.h @@ -138,7 +138,7 @@ extern void __init efi_apply_memmap_quirks(void); extern int __init efi_reuse_config(u64 tables, int nr_tables); extern void efi_delete_dummy_variable(void); extern void efi_crash_gracefully_on_page_fault(unsigned long phys_addr); -extern void efi_free_boot_services(void); +extern void efi_unmap_boot_services(void); void arch_efi_call_virt_setup(void); void arch_efi_call_virt_teardown(void); diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index e9f99c56f3ce..55a61aaa3303 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -860,7 +860,7 @@ static void __init __efi_enter_virtual_mode(void) } efi_check_for_embedded_firmwares(); - efi_free_boot_services(); + efi_unmap_boot_services(); if (!efi_is_mixed()) efi_native_runtime_setup(); diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c index f0cc00032751..df3b45ef1420 100644 --- a/arch/x86/platform/efi/quirks.c +++ b/arch/x86/platform/efi/quirks.c @@ -341,7 +341,7 @@ void __init efi_reserve_boot_services(void) /* * Because the following memblock_reserve() is paired - * with memblock_free_late() for this region in + * with free_reserved_area() for this region in * efi_free_boot_services(), we must be extremely * careful not to reserve, and subsequently free, * critical regions of memory (like the kernel image) or @@ -404,17 +404,33 @@ static void __init efi_unmap_pages(efi_memory_desc_t *md) pr_err("Failed to unmap VA mapping for 0x%llx\n", va); } -void __init efi_free_boot_services(void) +struct efi_freeable_range { + u64 start; + u64 end; +}; + +static struct efi_freeable_range *ranges_to_free; + +void __init efi_unmap_boot_services(void) { struct efi_memory_map_data data = { 0 }; efi_memory_desc_t *md; int num_entries = 0; + int idx = 0; + size_t sz; void *new, *new_md; /* Keep all regions for /sys/kernel/debug/efi */ if (efi_enabled(EFI_DBG)) return; + sz = sizeof(*ranges_to_free) * efi.memmap.nr_map + 1; + ranges_to_free = kzalloc(sz, GFP_KERNEL); + if (!ranges_to_free) { + pr_err("Failed to allocate storage for freeable EFI regions\n"); + return; + } + for_each_efi_memory_desc(md) { unsigned long long start = md->phys_addr; unsigned long long size = md->num_pages << EFI_PAGE_SHIFT; @@ -471,7 +487,15 @@ void __init efi_free_boot_services(void) start = SZ_1M; } - memblock_free_late(start, size); + /* + * With CONFIG_DEFERRED_STRUCT_PAGE_INIT parts of the memory + * map are still not initialized and we can't reliably free + * memory here. + * Queue the ranges to free at a later point. + */ + ranges_to_free[idx].start = start; + ranges_to_free[idx].end = start + size; + idx++; } if (!num_entries) @@ -512,6 +536,31 @@ void __init efi_free_boot_services(void) } } +static int __init efi_free_boot_services(void) +{ + struct efi_freeable_range *range = ranges_to_free; + unsigned long freed = 0; + + if (!ranges_to_free) + return 0; + + while (range->start) { + void *start = phys_to_virt(range->start); + void *end = phys_to_virt(range->end); + + free_reserved_area(start, end, -1, NULL); + freed += (end - start); + range++; + } + kfree(ranges_to_free); + + if (freed) + pr_info("Freeing EFI boot services memory: %ldK\n", freed / SZ_1K); + + return 0; +} +arch_initcall(efi_free_boot_services); + /* * A number of config table entries get remapped to virtual addresses * after entering EFI virtual mode. However, the kexec kernel requires diff --git a/drivers/firmware/efi/mokvar-table.c b/drivers/firmware/efi/mokvar-table.c index 4eb0dff4dfaf..bd84a22805b5 100644 --- a/drivers/firmware/efi/mokvar-table.c +++ b/drivers/firmware/efi/mokvar-table.c @@ -85,7 +85,7 @@ static struct kobject *mokvar_kobj; * as an alternative to ordinary EFI variables, due to platform-dependent * limitations. The memory occupied by this table is marked as reserved. * - * This routine must be called before efi_free_boot_services() in order + * This routine must be called before efi_unmap_boot_services() in order * to guarantee that it can mark the table as reserved. * * Implicit inputs: -- 2.34.1

2 1

[PATCH OLK-6.6] regmap: maple: free entry on mas_store_gfp() failure
by Lin Ruifeng 28 Mar '26

28 Mar '26

From: Kaushlendra Kumar <kaushlendra.kumar(a)intel.com> stable inclusion from stable-v6.6.124 commit d61171cf097156030142643942c217759a9cc806 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/13884 CVE: CVE-2026-23260 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- [ Upstream commit f3f380ce6b3d5c9805c7e0b3d5bc28d9ec41e2e8 ] regcache_maple_write() allocates a new block ('entry') to merge adjacent ranges and then stores it with mas_store_gfp(). When mas_store_gfp() fails, the new 'entry' remains allocated and is never freed, leaking memory. Free 'entry' on the failure path; on success continue freeing the replaced neighbor blocks ('lower', 'upper'). Signed-off-by: Kaushlendra Kumar <kaushlendra.kumar(a)intel.com> Link: https://patch.msgid.link/20260105031820.260119-1-kaushlendra.kumar@intel.com Signed-off-by: Mark Brown <broonie(a)kernel.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> Signed-off-by: Lin Ruifeng <linruifeng4(a)huawei.com> --- drivers/base/regmap/regcache-maple.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/drivers/base/regmap/regcache-maple.c b/drivers/base/regmap/regcache-maple.c index fb5761a5ef6e..86de71ce2c19 100644 --- a/drivers/base/regmap/regcache-maple.c +++ b/drivers/base/regmap/regcache-maple.c @@ -96,12 +96,13 @@ static int regcache_maple_write(struct regmap *map, unsigned int reg, mas_unlock(&mas); - if (ret == 0) { - kfree(lower); - kfree(upper); + if (ret) { + kfree(entry); + return ret; } - - return ret; + kfree(lower); + kfree(upper); + return 0; } static int regcache_maple_drop(struct regmap *map, unsigned int min, -- 2.43.0

2 1

[PATCH openEuler-1.0-LTS] bpf: Fix NULL event->prog pointer access in bpf_overflow_handler
by Pu Lehui 27 Mar '26

27 Mar '26

From: Yonghong Song <yhs(a)fb.com> mainline inclusion from mainline-v5.15-rc1 commit 594286b7574c6e8217b1c233cc0d0650f2268a77 category: bugfix bugzilla: https://atomgit.com/openeuler/kernel/issues/8819 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… -------------------------------- Andrii reported that libbpf CI hit the following oops when running selftest send_signal: [ 1243.160719] BUG: kernel NULL pointer dereference, address: 0000000000000030 [ 1243.161066] #PF: supervisor read access in kernel mode [ 1243.161066] #PF: error_code(0x0000) - not-present page [ 1243.161066] PGD 0 P4D 0 [ 1243.161066] Oops: 0000 [#1] PREEMPT SMP NOPTI [ 1243.161066] CPU: 1 PID: 882 Comm: new_name Tainted: G O 5.14.0-rc5 #1 [ 1243.161066] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 [ 1243.161066] RIP: 0010:bpf_overflow_handler+0x9a/0x1e0 [ 1243.161066] Code: 5a 84 c0 0f 84 06 01 00 00 be 66 02 00 00 48 c7 c7 6d 96 07 82 48 8b ab 18 05 00 00 e8 df 55 eb ff 66 90 48 8d 75 48 48 89 e7 <ff> 55 30 41 89 c4 e8 fb c1 f0 ff 84 c0 0f 84 94 00 00 00 e8 6e 0f [ 1243.161066] RSP: 0018:ffffc900000c0d80 EFLAGS: 00000046 [ 1243.161066] RAX: 0000000000000002 RBX: ffff8881002e0dd0 RCX: 00000000b4b47cf8 [ 1243.161066] RDX: ffffffff811dcb06 RSI: 0000000000000048 RDI: ffffc900000c0d80 [ 1243.161066] RBP: 0000000000000000 R08: 0000000000000000 R09: 1a9d56bb00000000 [ 1243.161066] R10: 0000000000000001 R11: 0000000000080000 R12: 0000000000000000 [ 1243.161066] R13: ffffc900000c0e00 R14: ffffc900001c3c68 R15: 0000000000000082 [ 1243.161066] FS: 00007fc0be2d3380(0000) GS:ffff88813bd00000(0000) knlGS:0000000000000000 [ 1243.161066] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1243.161066] CR2: 0000000000000030 CR3: 0000000104f8e000 CR4: 00000000000006e0 [ 1243.161066] Call Trace: [ 1243.161066] <IRQ> [ 1243.161066] __perf_event_overflow+0x4f/0xf0 [ 1243.161066] perf_swevent_hrtimer+0x116/0x130 [ 1243.161066] ? __lock_acquire+0x378/0x2730 [ 1243.161066] ? __lock_acquire+0x372/0x2730 [ 1243.161066] ? lock_is_held_type+0xd5/0x130 [ 1243.161066] ? find_held_lock+0x2b/0x80 [ 1243.161066] ? lock_is_held_type+0xd5/0x130 [ 1243.161066] ? perf_event_groups_first+0x80/0x80 [ 1243.161066] ? perf_event_groups_first+0x80/0x80 [ 1243.161066] __hrtimer_run_queues+0x1a3/0x460 [ 1243.161066] hrtimer_interrupt+0x110/0x220 [ 1243.161066] __sysvec_apic_timer_interrupt+0x8a/0x260 [ 1243.161066] sysvec_apic_timer_interrupt+0x89/0xc0 [ 1243.161066] </IRQ> [ 1243.161066] asm_sysvec_apic_timer_interrupt+0x12/0x20 [ 1243.161066] RIP: 0010:finish_task_switch+0xaf/0x250 [ 1243.161066] Code: 31 f6 68 90 2a 09 81 49 8d 7c 24 18 e8 aa d6 03 00 4c 89 e7 e8 12 ff ff ff 4c 89 e7 e8 ca 9c 80 00 e8 35 af 0d 00 fb 4d 85 f6 <58> 74 1d 65 48 8b 04 25 c0 6d 01 00 4c 3b b0 a0 04 00 00 74 37 f0 [ 1243.161066] RSP: 0018:ffffc900001c3d18 EFLAGS: 00000282 [ 1243.161066] RAX: 000000000000031f RBX: ffff888104cf4980 RCX: 0000000000000000 [ 1243.161066] RDX: 0000000000000000 RSI: ffffffff82095460 RDI: ffffffff820adc4e [ 1243.161066] RBP: ffffc900001c3d58 R08: 0000000000000001 R09: 0000000000000001 [ 1243.161066] R10: 0000000000000001 R11: 0000000000080000 R12: ffff88813bd2bc80 [ 1243.161066] R13: ffff8881002e8000 R14: ffff88810022ad80 R15: 0000000000000000 [ 1243.161066] ? finish_task_switch+0xab/0x250 [ 1243.161066] ? finish_task_switch+0x70/0x250 [ 1243.161066] __schedule+0x36b/0xbb0 [ 1243.161066] ? _raw_spin_unlock_irqrestore+0x2d/0x50 [ 1243.161066] ? lockdep_hardirqs_on+0x79/0x100 [ 1243.161066] schedule+0x43/0xe0 [ 1243.161066] pipe_read+0x30b/0x450 [ 1243.161066] ? wait_woken+0x80/0x80 [ 1243.161066] new_sync_read+0x164/0x170 [ 1243.161066] vfs_read+0x122/0x1b0 [ 1243.161066] ksys_read+0x93/0xd0 [ 1243.161066] do_syscall_64+0x35/0x80 [ 1243.161066] entry_SYSCALL_64_after_hwframe+0x44/0xae The oops can also be reproduced with the following steps: ./vmtest.sh -s # at qemu shell cd /root/bpf && while true; do ./test_progs -t send_signal Further analysis showed that the failure is introduced with commit b89fbfbb854c ("bpf: Implement minimal BPF perf link"). With the above commit, the following scenario becomes possible: cpu1 cpu2 hrtimer_interrupt -> bpf_overflow_handler (due to closing link_fd) bpf_perf_link_release -> perf_event_free_bpf_prog -> perf_event_free_bpf_handler -> WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler) event->prog = NULL bpf_prog_run(event->prog, &ctx) In the above case, the event->prog is NULL for bpf_prog_run, hence causing oops. To fix the issue, check whether event->prog is NULL or not. If it is, do not call bpf_prog_run. This seems working as the above reproducible step runs more than one hour and I didn't see any failures. Fixes: b89fbfbb854c ("bpf: Implement minimal BPF perf link") Signed-off-by: Yonghong Song <yhs(a)fb.com> Signed-off-by: Andrii Nakryiko <andrii(a)kernel.org> Link: https://lore.kernel.org/bpf/20210819155209.1927994-1-yhs@fb.com Conflicts: kernel/events/core.c [ctx conflicts] Signed-off-by: Pu Lehui <pulehui(a)huawei.com> --- kernel/events/core.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index ff875ddf4aeb..372450750559 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -8747,6 +8747,7 @@ static void bpf_overflow_handler(struct perf_event *event, .data = data, .event = event, }; + struct bpf_prog *prog; int ret = 0; ctx.regs = perf_arch_bpf_user_pt_regs(regs); @@ -8754,7 +8755,9 @@ static void bpf_overflow_handler(struct perf_event *event, if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) goto out; rcu_read_lock(); - ret = BPF_PROG_RUN(event->prog, &ctx); + prog = READ_ONCE(event->prog); + if (prog) + ret = BPF_PROG_RUN(prog, &ctx); rcu_read_unlock(); out: __this_cpu_dec(bpf_prog_active); -- 2.34.1

2 1

[PATCH OLK-5.10] bpf: Fix NULL event->prog pointer access in bpf_overflow_handler
by Pu Lehui 27 Mar '26

27 Mar '26

From: Yonghong Song <yhs(a)fb.com> mainline inclusion from mainline-v5.15-rc1 commit 594286b7574c6e8217b1c233cc0d0650f2268a77 category: bugfix bugzilla: https://atomgit.com/openeuler/kernel/issues/8819 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… -------------------------------- Andrii reported that libbpf CI hit the following oops when running selftest send_signal: [ 1243.160719] BUG: kernel NULL pointer dereference, address: 0000000000000030 [ 1243.161066] #PF: supervisor read access in kernel mode [ 1243.161066] #PF: error_code(0x0000) - not-present page [ 1243.161066] PGD 0 P4D 0 [ 1243.161066] Oops: 0000 [#1] PREEMPT SMP NOPTI [ 1243.161066] CPU: 1 PID: 882 Comm: new_name Tainted: G O 5.14.0-rc5 #1 [ 1243.161066] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 [ 1243.161066] RIP: 0010:bpf_overflow_handler+0x9a/0x1e0 [ 1243.161066] Code: 5a 84 c0 0f 84 06 01 00 00 be 66 02 00 00 48 c7 c7 6d 96 07 82 48 8b ab 18 05 00 00 e8 df 55 eb ff 66 90 48 8d 75 48 48 89 e7 <ff> 55 30 41 89 c4 e8 fb c1 f0 ff 84 c0 0f 84 94 00 00 00 e8 6e 0f [ 1243.161066] RSP: 0018:ffffc900000c0d80 EFLAGS: 00000046 [ 1243.161066] RAX: 0000000000000002 RBX: ffff8881002e0dd0 RCX: 00000000b4b47cf8 [ 1243.161066] RDX: ffffffff811dcb06 RSI: 0000000000000048 RDI: ffffc900000c0d80 [ 1243.161066] RBP: 0000000000000000 R08: 0000000000000000 R09: 1a9d56bb00000000 [ 1243.161066] R10: 0000000000000001 R11: 0000000000080000 R12: 0000000000000000 [ 1243.161066] R13: ffffc900000c0e00 R14: ffffc900001c3c68 R15: 0000000000000082 [ 1243.161066] FS: 00007fc0be2d3380(0000) GS:ffff88813bd00000(0000) knlGS:0000000000000000 [ 1243.161066] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1243.161066] CR2: 0000000000000030 CR3: 0000000104f8e000 CR4: 00000000000006e0 [ 1243.161066] Call Trace: [ 1243.161066] <IRQ> [ 1243.161066] __perf_event_overflow+0x4f/0xf0 [ 1243.161066] perf_swevent_hrtimer+0x116/0x130 [ 1243.161066] ? __lock_acquire+0x378/0x2730 [ 1243.161066] ? __lock_acquire+0x372/0x2730 [ 1243.161066] ? lock_is_held_type+0xd5/0x130 [ 1243.161066] ? find_held_lock+0x2b/0x80 [ 1243.161066] ? lock_is_held_type+0xd5/0x130 [ 1243.161066] ? perf_event_groups_first+0x80/0x80 [ 1243.161066] ? perf_event_groups_first+0x80/0x80 [ 1243.161066] __hrtimer_run_queues+0x1a3/0x460 [ 1243.161066] hrtimer_interrupt+0x110/0x220 [ 1243.161066] __sysvec_apic_timer_interrupt+0x8a/0x260 [ 1243.161066] sysvec_apic_timer_interrupt+0x89/0xc0 [ 1243.161066] </IRQ> [ 1243.161066] asm_sysvec_apic_timer_interrupt+0x12/0x20 [ 1243.161066] RIP: 0010:finish_task_switch+0xaf/0x250 [ 1243.161066] Code: 31 f6 68 90 2a 09 81 49 8d 7c 24 18 e8 aa d6 03 00 4c 89 e7 e8 12 ff ff ff 4c 89 e7 e8 ca 9c 80 00 e8 35 af 0d 00 fb 4d 85 f6 <58> 74 1d 65 48 8b 04 25 c0 6d 01 00 4c 3b b0 a0 04 00 00 74 37 f0 [ 1243.161066] RSP: 0018:ffffc900001c3d18 EFLAGS: 00000282 [ 1243.161066] RAX: 000000000000031f RBX: ffff888104cf4980 RCX: 0000000000000000 [ 1243.161066] RDX: 0000000000000000 RSI: ffffffff82095460 RDI: ffffffff820adc4e [ 1243.161066] RBP: ffffc900001c3d58 R08: 0000000000000001 R09: 0000000000000001 [ 1243.161066] R10: 0000000000000001 R11: 0000000000080000 R12: ffff88813bd2bc80 [ 1243.161066] R13: ffff8881002e8000 R14: ffff88810022ad80 R15: 0000000000000000 [ 1243.161066] ? finish_task_switch+0xab/0x250 [ 1243.161066] ? finish_task_switch+0x70/0x250 [ 1243.161066] __schedule+0x36b/0xbb0 [ 1243.161066] ? _raw_spin_unlock_irqrestore+0x2d/0x50 [ 1243.161066] ? lockdep_hardirqs_on+0x79/0x100 [ 1243.161066] schedule+0x43/0xe0 [ 1243.161066] pipe_read+0x30b/0x450 [ 1243.161066] ? wait_woken+0x80/0x80 [ 1243.161066] new_sync_read+0x164/0x170 [ 1243.161066] vfs_read+0x122/0x1b0 [ 1243.161066] ksys_read+0x93/0xd0 [ 1243.161066] do_syscall_64+0x35/0x80 [ 1243.161066] entry_SYSCALL_64_after_hwframe+0x44/0xae The oops can also be reproduced with the following steps: ./vmtest.sh -s # at qemu shell cd /root/bpf && while true; do ./test_progs -t send_signal Further analysis showed that the failure is introduced with commit b89fbfbb854c ("bpf: Implement minimal BPF perf link"). With the above commit, the following scenario becomes possible: cpu1 cpu2 hrtimer_interrupt -> bpf_overflow_handler (due to closing link_fd) bpf_perf_link_release -> perf_event_free_bpf_prog -> perf_event_free_bpf_handler -> WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler) event->prog = NULL bpf_prog_run(event->prog, &ctx) In the above case, the event->prog is NULL for bpf_prog_run, hence causing oops. To fix the issue, check whether event->prog is NULL or not. If it is, do not call bpf_prog_run. This seems working as the above reproducible step runs more than one hour and I didn't see any failures. Fixes: b89fbfbb854c ("bpf: Implement minimal BPF perf link") Signed-off-by: Yonghong Song <yhs(a)fb.com> Signed-off-by: Andrii Nakryiko <andrii(a)kernel.org> Link: https://lore.kernel.org/bpf/20210819155209.1927994-1-yhs@fb.com Conflicts: kernel/events/core.c [ctx conflicts] Signed-off-by: Pu Lehui <pulehui(a)huawei.com> --- kernel/events/core.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index d1ffd5fb9c6f..a46f2cefc031 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -9728,13 +9728,16 @@ static void bpf_overflow_handler(struct perf_event *event, .data = data, .event = event, }; + struct bpf_prog *prog; int ret = 0; ctx.regs = perf_arch_bpf_user_pt_regs(regs); if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) goto out; rcu_read_lock(); - ret = BPF_PROG_RUN(event->prog, &ctx); + prog = READ_ONCE(event->prog); + if (prog) + ret = BPF_PROG_RUN(prog, &ctx); rcu_read_unlock(); out: __this_cpu_dec(bpf_prog_active); -- 2.34.1

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[PATCH OLK-6.6 0/4] CVE-2026-23320
by Jinjie Ruan 27 Mar '26

27 Mar '26

CVE-2026-23320 Christian Brauner (1): file: add take_fd() cleanup helper Kuen-Han Tsai (1): usb: gadget: f_ncm: Fix net_device lifecycle with device_move Peter Zijlstra (1): cleanup: Make no_free_ptr() __must_check Thomas Gleixner (1): cleanup: Provide retain_and_null_ptr() drivers/usb/gadget/function/f_ncm.c | 35 ++++++++++----- drivers/usb/gadget/function/u_ether.c | 22 ++++++++++ drivers/usb/gadget/function/u_ether.h | 26 ++++++++++++ drivers/usb/gadget/function/u_ncm.h | 2 +- include/linux/cleanup.h | 61 +++++++++++++++++++++++++-- include/linux/file.h | 20 +++++++++ 6 files changed, 151 insertions(+), 15 deletions(-) -- 2.34.1

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[PATCH OLK-5.10 0/2] fix queue start/stop imbalance under race
by Zheng Qixing 27 Mar '26

27 Mar '26

Zheng Qixing (2): dm: fix queue start/stop imbalance under suspend/load/resume races dm: fix queue start/stop imbalance under remove/resume races drivers/md/dm-core.h | 1 + drivers/md/dm.c | 11 ++++++++--- 2 files changed, 9 insertions(+), 3 deletions(-) -- 2.39.2

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[PATCH OLK-6.6 0/2] fix queue start/stop imbalance under race
by Zheng Qixing 27 Mar '26

27 Mar '26

Zheng Qixing (2): dm: fix queue start/stop imbalance under suspend/load/resume races dm: fix queue start/stop imbalance under remove/resume races drivers/md/dm-core.h | 1 + drivers/md/dm.c | 11 ++++++++--- 2 files changed, 9 insertions(+), 3 deletions(-) -- 2.39.2

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[PATCH OLK-6.6 0/2] CVE-2026-23296
by Li Lingfeng 27 Mar '26

27 Mar '26

Junxiao Bi (2): scsi: core: Fix refcount leak for tagset_refcnt scsi: core: Fix error handling for scsi_alloc_sdev() drivers/scsi/scsi_scan.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) -- 2.52.0

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[PATCH OLK-6.6 0/2] fix queue start/stop imbalance under race
by Zheng Qixing 27 Mar '26

27 Mar '26

Zheng Qixing (2): dm: fix queue start/stop imbalance under suspend/load/resume races dm: fix queue start/stop imbalance under remove/resume races drivers/md/dm-core.h | 1 + drivers/md/dm.c | 11 ++++++++--- 2 files changed, 9 insertions(+), 3 deletions(-) -- 2.39.2

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