mm/page_alloc: prevent pcp corruption with SMP=n

Summary

CVECVE-2026-23025
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-01-31 12:16:05 UTC
Updated2026-06-02 14:16:46 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: mm/page_alloc: prevent pcp corruption with SMP=n The kernel test robot has reported: BUG: spinlock trylock failure on UP on CPU#0, kcompactd0/28 lock: 0xffff888807e35ef0, .magic: dead4ead, .owner: kcompactd0/28, .owner_cpu: 0 CPU: 0 UID: 0 PID: 28 Comm: kcompactd0 Not tainted 6.18.0-rc5-00127-ga06157804399 #1 PREEMPT 8cc09ef94dcec767faa911515ce9e609c45db470 Call Trace: <IRQ> __dump_stack (lib/dump_stack.c:95) dump_stack_lvl (lib/dump_stack.c:123) dump_stack (lib/dump_stack.c:130) spin_dump (kernel/locking/spinlock_debug.c:71) do_raw_spin_trylock (kernel/locking/spinlock_debug.c:?) _raw_spin_trylock (include/linux/spinlock_api_smp.h:89 kernel/locking/spinlock.c:138) __free_frozen_pages (mm/page_alloc.c:2973) ___free_pages (mm/page_alloc.c:5295) __free_pages (mm/page_alloc.c:5334) tlb_remove_table_rcu (include/linux/mm.h:? include/linux/mm.h:3122 include/asm-generic/tlb.h:220 mm/mmu_gather.c:227 mm/mmu_gather.c:290) ? __cfi_tlb_remove_table_rcu (mm/mmu_gather.c:289) ? rcu_core (kernel/rcu/tree.c:?) rcu_core (include/linux/rcupdate.h:341 kernel/rcu/tree.c:2607 kernel/rcu/tree.c:2861) rcu_core_si (kernel/rcu/tree.c:2879) handle_softirqs (arch/x86/include/asm/jump_label.h:36 include/trace/events/irq.h:142 kernel/softirq.c:623) __irq_exit_rcu (arch/x86/include/asm/jump_label.h:36 kernel/softirq.c:725) irq_exit_rcu (kernel/softirq.c:741) sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1052) </IRQ> <TASK> RIP: 0010:_raw_spin_unlock_irqrestore (arch/x86/include/asm/preempt.h:95 include/linux/spinlock_api_smp.h:152 kernel/locking/spinlock.c:194) free_pcppages_bulk (mm/page_alloc.c:1494) drain_pages_zone (include/linux/spinlock.h:391 mm/page_alloc.c:2632) __drain_all_pages (mm/page_alloc.c:2731) drain_all_pages (mm/page_alloc.c:2747) kcompactd (mm/compaction.c:3115) kthread (kernel/kthread.c:465) ? __cfi_kcompactd (mm/compaction.c:3166) ? __cfi_kthread (kernel/kthread.c:412) ret_from_fork (arch/x86/kernel/process.c:164) ? __cfi_kthread (kernel/kthread.c:412) ret_from_fork_asm (arch/x86/entry/entry_64.S:255) </TASK> Matthew has analyzed the report and identified that in drain_page_zone() we are in a section protected by spin_lock(&pcp->lock) and then get an interrupt that attempts spin_trylock() on the same lock. The code is designed to work this way without disabling IRQs and occasionally fail the trylock with a fallback. However, the SMP=n spinlock implementation assumes spin_trylock() will always succeed, and thus it's normally a no-op. Here the enabled lock debugging catches the problem, but otherwise it could cause a corruption of the pcp structure. The problem has been introduced by commit 574907741599 ("mm/page_alloc: leave IRQs enabled for per-cpu page allocations"). The pcp locking scheme recognizes the need for disabling IRQs to prevent nesting spin_trylock() sections on SMP=n, but the need to prevent the nesting in spin_lock() has not been recognized. Fix it by introducing local wrappers that change the spin_lock() to spin_lock_iqsave() with SMP=n and use them in all places that do spin_lock(&pcp->lock). [[email protected]: add pcp_ prefix to the spin_lock_irqsave wrappers, per Steven]

Risk And Classification

Primary CVSS: v3.1 7.8 HIGH from [email protected]

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Problem Types: NVD-CWE-noinfo

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Linux Linux Kernel All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected d1da921452b3ee7e07383c12955ab1c6f3b08752 68688fc4eab007834b4c2d740214423ba2a335a8 git Not specified
CNA Linux Linux affected 5749077415994eb02d660b2559b9d8278521e73d 4a04ff9cd816e7346fcc8126f00ed80481f6569d git Not specified
CNA Linux Linux affected 5749077415994eb02d660b2559b9d8278521e73d df63d31e9ae02e2f6cd96147779e4ed7cd0e75f6 git Not specified
CNA Linux Linux affected 5749077415994eb02d660b2559b9d8278521e73d 3098f8f7c7b0686c74827aec42a2c45e69801ff8 git Not specified
CNA Linux Linux affected 5749077415994eb02d660b2559b9d8278521e73d 038a102535eb49e10e93eafac54352fcc5d78847 git Not specified
CNA Linux Linux affected 6.1.57 6.1.162 semver Not specified
CNA Linux Linux affected 6.2 Not specified
CNA Linux Linux unaffected 6.2 semver Not specified
CNA Linux Linux unaffected 6.1.162 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.122 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.67 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.7 6.18.* semver Not specified
CNA Linux Linux unaffected 6.19 * original_commit_for_fix Not specified
ADP Siemens RUGGEDCOM RST2428P affected V4.0 custom Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/df63d31e9ae02e2f6cd96147779e4ed7cd0e75f6 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/4a04ff9cd816e7346fcc8126f00ed80481f6569d 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/3098f8f7c7b0686c74827aec42a2c45e69801ff8 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
cert-portal.siemens.com/productcert/html/ssa-253495.html 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e cert-portal.siemens.com
git.kernel.org/stable/c/038a102535eb49e10e93eafac54352fcc5d78847 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/68688fc4eab007834b4c2d740214423ba2a335a8 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
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