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[PATCH OLK-6.6] sched/fair: scale wake_wide() threshold by SMT width
by Zhang Qiao 07 Apr '26

07 Apr '26

hulk inclusion category: bugfix bugzilla: https://atomgit.com/openeuler/kernel/issues/8882 -------------------------------- wake_wide() uses sd_llc_size as the spreading threshold to detect wide waker/wakee relationships and to disable wake_affine() for those cases. On SMT systems, sd_llc_size counts logical CPUs rather than physical cores. This inflates the wake_wide() threshold, allowing wake_affine() to pack more tasks into one LLC domain than the actual compute capacity of its physical cores can sustain. The resulting SMT interference may cost more than the cache-locality benefit wake_affine() intends to gain. Scale the factor by the SMT width of the current CPU so that it approximates the number of independent physical cores in the LLC domain, making wake_wide() more likely to kick in before SMT interference becomes significant. On non-SMT systems the SMT width is 1 and behaviour is unchanged. Signed-off-by: Zhang Qiao <zhangqiao22(a)huawei.com> --- kernel/sched/fair.c | 5 +++++ kernel/sched/features.h | 2 ++ 2 files changed, 7 insertions(+) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index ad30bb800961..4100998e18cd 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -7850,6 +7850,11 @@ static int wake_wide(struct task_struct *p) unsigned int slave = p->wakee_flips; int factor = __this_cpu_read(sd_llc_size); + /* Scale factor to physical-core count to account for SMT interference. */ + if (sched_feat(WA_SMT)) + factor = DIV_ROUND_UP(factor, + cpumask_weight(cpu_smt_mask(smp_processor_id()))); + if (master < slave) swap(master, slave); if (slave < factor || master < slave * factor) diff --git a/kernel/sched/features.h b/kernel/sched/features.h index 24a0c853a8a0..c9ad8e72ecd0 100644 --- a/kernel/sched/features.h +++ b/kernel/sched/features.h @@ -128,3 +128,5 @@ SCHED_FEAT(SOFT_DOMAIN, false) #ifdef CONFIG_SCHED_SOFT_QUOTA SCHED_FEAT(SOFT_QUOTA, false) #endif + +SCHED_FEAT(WA_SMT, false) -- 2.18.0

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[PATCH OLK-6.6] sched/fair: scale wake_wide() threshold by SMT width
by Zhang Qiao 07 Apr '26

07 Apr '26

hulk inclusion category: perfermance bugzilla: https://atomgit.com/openeuler/kernel/issues/8882 -------------------------------- wake_wide() uses sd_llc_size as the spreading threshold to detect wide waker/wakee relationships and to disable wake_affine() for those cases. On SMT systems, sd_llc_size counts logical CPUs rather than physical cores. This inflates the wake_wide() threshold, allowing wake_affine() to pack more tasks into one LLC domain than the actual compute capacity of its physical cores can sustain. The resulting SMT interference may cost more than the cache-locality benefit wake_affine() intends to gain. Scale the factor by the SMT width of the current CPU so that it approximates the number of independent physical cores in the LLC domain, making wake_wide() more likely to kick in before SMT interference becomes significant. On non-SMT systems the SMT width is 1 and behaviour is unchanged. Signed-off-by: Zhang Qiao <zhangqiao22(a)huawei.com> --- kernel/sched/fair.c | 5 +++++ kernel/sched/features.h | 2 ++ 2 files changed, 7 insertions(+) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index ad30bb800961..4100998e18cd 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -7850,6 +7850,11 @@ static int wake_wide(struct task_struct *p) unsigned int slave = p->wakee_flips; int factor = __this_cpu_read(sd_llc_size); + /* Scale factor to physical-core count to account for SMT interference. */ + if (sched_feat(WA_SMT)) + factor = DIV_ROUND_UP(factor, + cpumask_weight(cpu_smt_mask(smp_processor_id()))); + if (master < slave) swap(master, slave); if (slave < factor || master < slave * factor) diff --git a/kernel/sched/features.h b/kernel/sched/features.h index 24a0c853a8a0..c9ad8e72ecd0 100644 --- a/kernel/sched/features.h +++ b/kernel/sched/features.h @@ -128,3 +128,5 @@ SCHED_FEAT(SOFT_DOMAIN, false) #ifdef CONFIG_SCHED_SOFT_QUOTA SCHED_FEAT(SOFT_QUOTA, false) #endif + +SCHED_FEAT(WA_SMT, false) -- 2.18.0

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[PATCH OLK-5.10] x86/uprobes: Fix XOL allocation failure for 32-bit tasks
by Pan Taixi 07 Apr '26

07 Apr '26

From: Oleg Nesterov <oleg(a)redhat.com> mainline inclusion from mainline-v7.0-rc1 commit d55c571e4333fac71826e8db3b9753fadfbead6a category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/14049/ Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… -------------------------------- This script #!/usr/bin/bash echo 0 > /proc/sys/kernel/randomize_va_space echo 'void main(void) {}' > TEST.c # -fcf-protection to ensure that the 1st endbr32 insn can't be emulated gcc -m32 -fcf-protection=branch TEST.c -o test bpftrace -e 'uprobe:./test:main {}' -c ./test "hangs", the probed ./test task enters an endless loop. The problem is that with randomize_va_space == 0 get_unmapped_area(TASK_SIZE - PAGE_SIZE) called by xol_add_vma() can not just return the "addr == TASK_SIZE - PAGE_SIZE" hint, this addr is used by the stack vma. arch_get_unmapped_area_topdown() doesn't take TIF_ADDR32 into account and in_32bit_syscall() is false, this leads to info.high_limit > TASK_SIZE. vm_unmapped_area() happily returns the high address > TASK_SIZE and then get_unmapped_area() returns -ENOMEM after the "if (addr > TASK_SIZE - len)" check. handle_swbp() doesn't report this failure (probably it should) and silently restarts the probed insn. Endless loop. I think that the right fix should change the x86 get_unmapped_area() paths to rely on TIF_ADDR32 rather than in_32bit_syscall(). Note also that if CONFIG_X86_X32_ABI=y, in_x32_syscall() falsely returns true in this case because ->orig_ax = -1. But we need a simple fix for -stable, so this patch just sets TS_COMPAT if the probed task is 32-bit to make in_ia32_syscall() true. Fixes: 1b028f784e8c ("x86/mm: Introduce mmap_compat_base() for 32-bit mmap()") Reported-by: Paulo Andrade <pandrade(a)redhat.com> Signed-off-by: Oleg Nesterov <oleg(a)redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org> Link: https://lore.kernel.org/all/aV5uldEvV7pb4RA8@redhat.com/ Cc: stable(a)vger.kernel.org Link: https://patch.msgid.link/aWO7Fdxn39piQnxu@redhat.com Conflicts: arch/x86/kernel/uprobes.c include/linux/uprobes.h kernel/events/uprobes.c [Context conflicts only] Signed-off-by: Pan Taixi <pantaixi1(a)huawei.com> --- arch/x86/kernel/uprobes.c | 24 ++++++++++++++++++++++++ include/linux/uprobes.h | 1 + kernel/events/uprobes.c | 10 +++++++--- 3 files changed, 32 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c index 9f948b2d26f6..099ca674e3de 100644 --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -1095,3 +1095,27 @@ bool arch_uretprobe_is_alive(struct return_instance *ret, enum rp_check ctx, else return regs->sp <= ret->stack; } + +#ifdef CONFIG_IA32_EMULATION +unsigned long arch_uprobe_get_xol_area(void) +{ + struct thread_info *ti = current_thread_info(); + unsigned long vaddr; + + /* + * HACK: we are not in a syscall, but x86 get_unmapped_area() paths + * ignore TIF_ADDR32 and rely on in_32bit_syscall() to calculate + * vm_unmapped_area_info.high_limit. + * + * The #ifdef above doesn't cover the CONFIG_X86_X32_ABI=y case, + * but in this case in_32bit_syscall() -> in_x32_syscall() always + * (falsely) returns true because ->orig_ax == -1. + */ + if (test_thread_flag(TIF_ADDR32)) + ti->status |= TS_COMPAT; + vaddr = get_unmapped_area(NULL, TASK_SIZE - PAGE_SIZE, PAGE_SIZE, 0, 0); + ti->status &= ~TS_COMPAT; + + return vaddr; +} +#endif diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h index 2c693d6eb9cb..568c211b617e 100644 --- a/include/linux/uprobes.h +++ b/include/linux/uprobes.h @@ -144,6 +144,7 @@ extern bool arch_uretprobe_is_alive(struct return_instance *ret, enum rp_check c extern bool arch_uprobe_ignore(struct arch_uprobe *aup, struct pt_regs *regs); extern void arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr, void *src, unsigned long len); +extern unsigned long arch_uprobe_get_xol_area(void); #else /* !CONFIG_UPROBES */ struct uprobes_state { }; diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index e51dbb0e8a56..fe518be0615f 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1443,6 +1443,12 @@ void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned lon set_bit(MMF_RECALC_UPROBES, &vma->vm_mm->flags); } +unsigned long __weak arch_uprobe_get_xol_area(void) +{ + /* Try to map as high as possible, this is only a hint. */ + return get_unmapped_area(NULL, TASK_SIZE - PAGE_SIZE, PAGE_SIZE, 0, 0); +} + /* Slot allocation for XOL */ static int xol_add_vma(struct mm_struct *mm, struct xol_area *area) { @@ -1458,9 +1464,7 @@ static int xol_add_vma(struct mm_struct *mm, struct xol_area *area) } if (!area->vaddr) { - /* Try to map as high as possible, this is only a hint. */ - area->vaddr = get_unmapped_area(NULL, TASK_SIZE - PAGE_SIZE, - PAGE_SIZE, 0, 0); + area->vaddr = arch_uprobe_get_xol_area(); if (IS_ERR_VALUE(area->vaddr)) { ret = area->vaddr; goto fail; -- 2.34.1

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[PATCH OLK-6.6 0/2] Fix riscv check-build warning
by Tengda Wu 07 Apr '26

07 Apr '26

Fix rsicv check-build warning. Björn Töpel (1): riscv: Replace function-like macro by static inline function Tengda Wu (1): Revert "riscv: stacktrace: Disable KASAN checks for non-current tasks" arch/riscv/include/asm/cacheflush.h | 15 ++++++++++----- arch/riscv/kernel/stacktrace.c | 16 ---------------- 2 files changed, 10 insertions(+), 21 deletions(-) -- 2.34.1

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[PATCH OLK-6.6 0/2] Fix riscv compiling error
by Tengda Wu 07 Apr '26

07 Apr '26

Fix riscv compiling error. Björn Töpel (1): riscv: Replace function-like macro by static inline function Tengda Wu (1): Revert "riscv: stacktrace: Disable KASAN checks for non-current tasks" arch/riscv/include/asm/cacheflush.h | 15 ++++++++++----- arch/riscv/kernel/stacktrace.c | 19 ++----------------- 2 files changed, 12 insertions(+), 22 deletions(-) -- 2.34.1

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[PATCH OLK-6.6] ice: Fix memory leak in ice_set_ringparam()
by Pan Taixi 07 Apr '26

07 Apr '26

From: Zilin Guan <zilin(a)seu.edu.cn> mainline inclusion from mainline-v7.0-rc3 commit fe868b499d16f55bbeea89992edb98043c9de416 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/14020/ CVE: CVE-2026-23389 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… -------------------------------- In ice_set_ringparam, tx_rings and xdp_rings are allocated before rx_rings. If the allocation of rx_rings fails, the code jumps to the done label leaking both tx_rings and xdp_rings. Furthermore, if the setup of an individual Rx ring fails during the loop, the code jumps to the free_tx label which releases tx_rings but leaks xdp_rings. Fix this by introducing a free_xdp label and updating the error paths to ensure both xdp_rings and tx_rings are properly freed if rx_rings allocation or setup fails. Compile tested only. Issue found using a prototype static analysis tool and code review. Fixes: fcea6f3da546 ("ice: Add stats and ethtool support") Fixes: efc2214b6047 ("ice: Add support for XDP") Signed-off-by: Zilin Guan <zilin(a)seu.edu.cn> Reviewed-by: Paul Menzel <pmenzel(a)molgen.mpg.de> Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov(a)intel.com> Tested-by: Rinitha S <sx.rinitha(a)intel.com> (A Contingent worker at Intel) Signed-off-by: Tony Nguyen <anthony.l.nguyen(a)intel.com> Conflicts: drivers/net/ethernet/intel/ice/ice_ethtool.c [Context conflicts due to different memory allocation function used] Signed-off-by: Pan Taixi <pantaixi1(a)huawei.com> --- drivers/net/ethernet/intel/ice/ice_ethtool.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/intel/ice/ice_ethtool.c b/drivers/net/ethernet/intel/ice/ice_ethtool.c index dd58b2372dc0..bab857a6dc18 100644 --- a/drivers/net/ethernet/intel/ice/ice_ethtool.c +++ b/drivers/net/ethernet/intel/ice/ice_ethtool.c @@ -2839,7 +2839,7 @@ ice_set_ringparam(struct net_device *netdev, struct ethtool_ringparam *ring, rx_rings = kcalloc(vsi->num_rxq, sizeof(*rx_rings), GFP_KERNEL); if (!rx_rings) { err = -ENOMEM; - goto done; + goto free_xdp; } ice_for_each_rxq(vsi, i) { @@ -2869,7 +2869,7 @@ ice_set_ringparam(struct net_device *netdev, struct ethtool_ringparam *ring, } kfree(rx_rings); err = -ENOMEM; - goto free_tx; + goto free_xdp; } } @@ -2920,6 +2920,13 @@ ice_set_ringparam(struct net_device *netdev, struct ethtool_ringparam *ring, } goto done; +free_xdp: + if (xdp_rings) { + ice_for_each_xdp_txq(vsi, i) + ice_free_tx_ring(&xdp_rings[i]); + kfree(xdp_rings); + } + free_tx: /* error cleanup if the Rx allocations failed after getting Tx */ if (tx_rings) { -- 2.34.1

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[PATCH OLK-5.10] ice: Fix memory leak in ice_set_ringparam()
by Pan Taixi 07 Apr '26

07 Apr '26

From: Zilin Guan <zilin(a)seu.edu.cn> mainline inclusion from mainline-v7.0-rc3 commit fe868b499d16f55bbeea89992edb98043c9de416 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/14020/ CVE: CVE-2026-23389 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… -------------------------------- In ice_set_ringparam, tx_rings and xdp_rings are allocated before rx_rings. If the allocation of rx_rings fails, the code jumps to the done label leaking both tx_rings and xdp_rings. Furthermore, if the setup of an individual Rx ring fails during the loop, the code jumps to the free_tx label which releases tx_rings but leaks xdp_rings. Fix this by introducing a free_xdp label and updating the error paths to ensure both xdp_rings and tx_rings are properly freed if rx_rings allocation or setup fails. Compile tested only. Issue found using a prototype static analysis tool and code review. Fixes: fcea6f3da546 ("ice: Add stats and ethtool support") Fixes: efc2214b6047 ("ice: Add support for XDP") Signed-off-by: Zilin Guan <zilin(a)seu.edu.cn> Reviewed-by: Paul Menzel <pmenzel(a)molgen.mpg.de> Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov(a)intel.com> Tested-by: Rinitha S <sx.rinitha(a)intel.com> (A Contingent worker at Intel) Signed-off-by: Tony Nguyen <anthony.l.nguyen(a)intel.com> Conflicts: drivers/net/ethernet/intel/ice/ice_ethtool.c [ Context conflicts due to different memory allocation function used. Also, ice_for_each_xdp_txq is introduced in unmmerged commit 2faf63b650bb ("ice: make use of ice_for_each_* macros"), use normal for loops here instead. ] Signed-off-by: Pan Taixi <pantaixi1(a)huawei.com> --- drivers/net/ethernet/intel/ice/ice_ethtool.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/intel/ice/ice_ethtool.c b/drivers/net/ethernet/intel/ice/ice_ethtool.c index 9659668279dc..585ae5e92558 100644 --- a/drivers/net/ethernet/intel/ice/ice_ethtool.c +++ b/drivers/net/ethernet/intel/ice/ice_ethtool.c @@ -2865,7 +2865,7 @@ ice_set_ringparam(struct net_device *netdev, struct ethtool_ringparam *ring, rx_rings = kcalloc(vsi->num_rxq, sizeof(*rx_rings), GFP_KERNEL); if (!rx_rings) { err = -ENOMEM; - goto done; + goto free_xdp; } ice_for_each_rxq(vsi, i) { @@ -2894,7 +2894,7 @@ ice_set_ringparam(struct net_device *netdev, struct ethtool_ringparam *ring, } kfree(rx_rings); err = -ENOMEM; - goto free_tx; + goto free_xdp; } } @@ -2945,6 +2945,13 @@ ice_set_ringparam(struct net_device *netdev, struct ethtool_ringparam *ring, } goto done; +free_xdp: + if (xdp_rings) { + for (i = 0; i < vsi->num_xdp_txq; i++) + ice_free_tx_ring(&xdp_rings[i]); + kfree(xdp_rings); + } + free_tx: /* error cleanup if the Rx allocations failed after getting Tx */ if (tx_rings) { -- 2.34.1

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[PATCH OLK-6.6] pstore/ram: fix buffer overflow in persistent_ram_save_old()
by Pan Taixi 07 Apr '26

07 Apr '26

From: Sai Ritvik Tanksalkar <stanksal(a)purdue.edu> stable inclusion from stable-v6.6.128 commit cff0ef043e16feb5a02307c8f9d0117a96c5587c category: bugfix bugzilla: https://atomgit.com/openeuler/kernel/issues/8792 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- [ Upstream commit 5669645c052f235726a85f443769b6fc02f66762 ] persistent_ram_save_old() can be called multiple times for the same persistent_ram_zone (e.g., via ramoops_pstore_read -> ramoops_get_next_prz for PSTORE_TYPE_DMESG records). Currently, the function only allocates prz->old_log when it is NULL, but it unconditionally updates prz->old_log_size to the current buffer size and then performs memcpy_fromio() using this new size. If the buffer size has grown since the first allocation (which can happen across different kernel boot cycles), this leads to: 1. A heap buffer overflow (OOB write) in the memcpy_fromio() calls 2. A subsequent OOB read when ramoops_pstore_read() accesses the buffer using the incorrect (larger) old_log_size The KASAN splat would look similar to: BUG: KASAN: slab-out-of-bounds in ramoops_pstore_read+0x... Read of size N at addr ... by task ... The conditions are likely extremely hard to hit: 0. Crash with a ramoops write of less-than-record-max-size bytes. 1. Reboot: ramoops registers, pstore_get_records(0) reads old crash, allocates old_log with size X 2. Crash handler registered, timer started (if pstore_update_ms >= 0) 3. Oops happens (non-fatal, system continues) 4. pstore_dump() writes oops via ramoops_pstore_write() size Y (>X) 5. pstore_new_entry = 1, pstore_timer_kick() called 6. System continues running (not a panic oops) 7. Timer fires after pstore_update_ms milliseconds 8. pstore_timefunc() → schedule_work() → pstore_dowork() → pstore_get_records(1) 9. ramoops_get_next_prz() → persistent_ram_save_old() 10. buffer_size() returns Y, but old_log is X bytes 11. Y > X: memcpy_fromio() overflows heap Requirements: - a prior crash record exists that did not fill the record size (almost impossible since the crash handler writes as much as it can possibly fit into the record, capped by max record size and the kmsg buffer almost always exceeds the max record size) - pstore_update_ms >= 0 (disabled by default) - Non-fatal oops (system survives) Free and reallocate the buffer when the new size differs from the previously allocated size. This ensures old_log always has sufficient space for the data being copied. Fixes: 201e4aca5aa1 ("pstore/ram: Should update old dmesg buffer before reading") Signed-off-by: Sai Ritvik Tanksalkar <stanksal(a)purdue.edu> Link: https://patch.msgid.link/20260201132240.2948732-1-stanksal@purdue.edu Signed-off-by: Kees Cook <kees(a)kernel.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> Signed-off-by: Yuan can <yuancan(a)huawei.com> Signed-off-by: Pan Taixi <pantaixi1(a)huawei.com> --- fs/pstore/ram_core.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c index f1848cdd6d34..c9eaacdec37e 100644 --- a/fs/pstore/ram_core.c +++ b/fs/pstore/ram_core.c @@ -298,6 +298,17 @@ void persistent_ram_save_old(struct persistent_ram_zone *prz) if (!size) return; + /* + * If the existing buffer is differently sized, free it so a new + * one is allocated. This can happen when persistent_ram_save_old() + * is called early in boot and later for a timer-triggered + * survivable crash when the crash dumps don't match in size + * (which would be extremely unlikely given kmsg buffers usually + * exceed prz buffer sizes). + */ + if (prz->old_log && prz->old_log_size != size) + persistent_ram_free_old(prz); + if (!prz->old_log) { persistent_ram_ecc_old(prz); prz->old_log = kvzalloc(size, GFP_KERNEL); -- 2.34.1

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[PATCH OLK-5.10] pstore/ram: fix buffer overflow in persistent_ram_save_old()
by Pan Taixi 07 Apr '26

07 Apr '26

From: Sai Ritvik Tanksalkar <stanksal(a)purdue.edu> stable inclusion from stable-v5.10.252 commit 58bda5a1d1ee98254383ef34f76b2c35140513ea category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/14048/ Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- [ Upstream commit 5669645c052f235726a85f443769b6fc02f66762 ] persistent_ram_save_old() can be called multiple times for the same persistent_ram_zone (e.g., via ramoops_pstore_read -> ramoops_get_next_prz for PSTORE_TYPE_DMESG records). Currently, the function only allocates prz->old_log when it is NULL, but it unconditionally updates prz->old_log_size to the current buffer size and then performs memcpy_fromio() using this new size. If the buffer size has grown since the first allocation (which can happen across different kernel boot cycles), this leads to: 1. A heap buffer overflow (OOB write) in the memcpy_fromio() calls 2. A subsequent OOB read when ramoops_pstore_read() accesses the buffer using the incorrect (larger) old_log_size The KASAN splat would look similar to: BUG: KASAN: slab-out-of-bounds in ramoops_pstore_read+0x... Read of size N at addr ... by task ... The conditions are likely extremely hard to hit: 0. Crash with a ramoops write of less-than-record-max-size bytes. 1. Reboot: ramoops registers, pstore_get_records(0) reads old crash, allocates old_log with size X 2. Crash handler registered, timer started (if pstore_update_ms >= 0) 3. Oops happens (non-fatal, system continues) 4. pstore_dump() writes oops via ramoops_pstore_write() size Y (>X) 5. pstore_new_entry = 1, pstore_timer_kick() called 6. System continues running (not a panic oops) 7. Timer fires after pstore_update_ms milliseconds 8. pstore_timefunc() → schedule_work() → pstore_dowork() → pstore_get_records(1) 9. ramoops_get_next_prz() → persistent_ram_save_old() 10. buffer_size() returns Y, but old_log is X bytes 11. Y > X: memcpy_fromio() overflows heap Requirements: - a prior crash record exists that did not fill the record size (almost impossible since the crash handler writes as much as it can possibly fit into the record, capped by max record size and the kmsg buffer almost always exceeds the max record size) - pstore_update_ms >= 0 (disabled by default) - Non-fatal oops (system survives) Free and reallocate the buffer when the new size differs from the previously allocated size. This ensures old_log always has sufficient space for the data being copied. Fixes: 201e4aca5aa1 ("pstore/ram: Should update old dmesg buffer before reading") Signed-off-by: Sai Ritvik Tanksalkar <stanksal(a)purdue.edu> Link: https://patch.msgid.link/20260201132240.2948732-1-stanksal@purdue.edu Signed-off-by: Kees Cook <kees(a)kernel.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> Signed-off-by: Lin Yujun <linyujun809(a)h-partners.com> Signed-off-by: Pan Taixi <pantaixi1(a)huawei.com> --- fs/pstore/ram_core.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c index 5ac9b1f155a8..97ec9041b9b9 100644 --- a/fs/pstore/ram_core.c +++ b/fs/pstore/ram_core.c @@ -298,6 +298,17 @@ void persistent_ram_save_old(struct persistent_ram_zone *prz) if (!size) return; + /* + * If the existing buffer is differently sized, free it so a new + * one is allocated. This can happen when persistent_ram_save_old() + * is called early in boot and later for a timer-triggered + * survivable crash when the crash dumps don't match in size + * (which would be extremely unlikely given kmsg buffers usually + * exceed prz buffer sizes). + */ + if (prz->old_log && prz->old_log_size != size) + persistent_ram_free_old(prz); + if (!prz->old_log) { persistent_ram_ecc_old(prz); prz->old_log = kmalloc(size, GFP_KERNEL); -- 2.34.1

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[PATCH OLK-6.6] x86/uprobes: Fix XOL allocation failure for 32-bit tasks
by Pan Taixi 07 Apr '26

07 Apr '26

From: Oleg Nesterov <oleg(a)redhat.com> stable inclusion from stable-v6.6.130 commit 9c05cd8f42325a53474093f372f6c08a56ae18d1 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/14049/ Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- [ Upstream commit d55c571e4333fac71826e8db3b9753fadfbead6a ] This script #!/usr/bin/bash echo 0 > /proc/sys/kernel/randomize_va_space echo 'void main(void) {}' > TEST.c # -fcf-protection to ensure that the 1st endbr32 insn can't be emulated gcc -m32 -fcf-protection=branch TEST.c -o test bpftrace -e 'uprobe:./test:main {}' -c ./test "hangs", the probed ./test task enters an endless loop. The problem is that with randomize_va_space == 0 get_unmapped_area(TASK_SIZE - PAGE_SIZE) called by xol_add_vma() can not just return the "addr == TASK_SIZE - PAGE_SIZE" hint, this addr is used by the stack vma. arch_get_unmapped_area_topdown() doesn't take TIF_ADDR32 into account and in_32bit_syscall() is false, this leads to info.high_limit > TASK_SIZE. vm_unmapped_area() happily returns the high address > TASK_SIZE and then get_unmapped_area() returns -ENOMEM after the "if (addr > TASK_SIZE - len)" check. handle_swbp() doesn't report this failure (probably it should) and silently restarts the probed insn. Endless loop. I think that the right fix should change the x86 get_unmapped_area() paths to rely on TIF_ADDR32 rather than in_32bit_syscall(). Note also that if CONFIG_X86_X32_ABI=y, in_x32_syscall() falsely returns true in this case because ->orig_ax = -1. But we need a simple fix for -stable, so this patch just sets TS_COMPAT if the probed task is 32-bit to make in_ia32_syscall() true. Fixes: 1b028f784e8c ("x86/mm: Introduce mmap_compat_base() for 32-bit mmap()") Reported-by: Paulo Andrade <pandrade(a)redhat.com> Signed-off-by: Oleg Nesterov <oleg(a)redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org> Link: https://lore.kernel.org/all/aV5uldEvV7pb4RA8@redhat.com/ Cc: stable(a)vger.kernel.org Link: https://patch.msgid.link/aWO7Fdxn39piQnxu@redhat.com Signed-off-by: Pan Taixi <pantaixi1(a)huawei.com> --- arch/x86/kernel/uprobes.c | 24 ++++++++++++++++++++++++ include/linux/uprobes.h | 1 + kernel/events/uprobes.c | 10 +++++++--- 3 files changed, 32 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c index 6402fb3089d2..aac2a2c5c6c5 100644 --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -1102,3 +1102,27 @@ bool arch_uretprobe_is_alive(struct return_instance *ret, enum rp_check ctx, else return regs->sp <= ret->stack; } + +#ifdef CONFIG_IA32_EMULATION +unsigned long arch_uprobe_get_xol_area(void) +{ + struct thread_info *ti = current_thread_info(); + unsigned long vaddr; + + /* + * HACK: we are not in a syscall, but x86 get_unmapped_area() paths + * ignore TIF_ADDR32 and rely on in_32bit_syscall() to calculate + * vm_unmapped_area_info.high_limit. + * + * The #ifdef above doesn't cover the CONFIG_X86_X32_ABI=y case, + * but in this case in_32bit_syscall() -> in_x32_syscall() always + * (falsely) returns true because ->orig_ax == -1. + */ + if (test_thread_flag(TIF_ADDR32)) + ti->status |= TS_COMPAT; + vaddr = get_unmapped_area(NULL, TASK_SIZE - PAGE_SIZE, PAGE_SIZE, 0, 0); + ti->status &= ~TS_COMPAT; + + return vaddr; +} +#endif diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h index b0c15a04adcc..7c63f47a497d 100644 --- a/include/linux/uprobes.h +++ b/include/linux/uprobes.h @@ -147,6 +147,7 @@ extern bool arch_uretprobe_is_alive(struct return_instance *ret, enum rp_check c extern bool arch_uprobe_ignore(struct arch_uprobe *aup, struct pt_regs *regs); extern void arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr, void *src, unsigned long len); +extern unsigned long arch_uprobe_get_xol_area(void); #else /* !CONFIG_UPROBES */ struct uprobes_state { }; diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 9d2d68d171e9..8f73ab934c38 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1478,6 +1478,12 @@ void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned lon set_bit(MMF_RECALC_UPROBES, &vma->vm_mm->flags); } +unsigned long __weak arch_uprobe_get_xol_area(void) +{ + /* Try to map as high as possible, this is only a hint. */ + return get_unmapped_area(NULL, TASK_SIZE - PAGE_SIZE, PAGE_SIZE, 0, 0); +} + /* Slot allocation for XOL */ static int xol_add_vma(struct mm_struct *mm, struct xol_area *area) { @@ -1493,9 +1499,7 @@ static int xol_add_vma(struct mm_struct *mm, struct xol_area *area) } if (!area->vaddr) { - /* Try to map as high as possible, this is only a hint. */ - area->vaddr = get_unmapped_area(NULL, TASK_SIZE - PAGE_SIZE, - PAGE_SIZE, 0, 0); + area->vaddr = arch_uprobe_get_xol_area(); if (IS_ERR_VALUE(area->vaddr)) { ret = area->vaddr; goto fail; -- 2.34.1

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