kernel/linux.git/mm/memory-failure.c, branch v6.12.80

mm/memory-failure: teach kill_accessing_process to accept hugetlb tail page pfn

2026-02-06T15:55:47+00:00

commit 057a6f2632c956483e2b2628477f0fcd1cd8a844 upstream. When a hugetlb folio is being poisoned again, try_memory_failure_hugetlb() passed head pfn to kill_accessing_process(), that is not right. The precise pfn of the poisoned page should be used in order to determine the precise vaddr as the SIGBUS payload. This issue has already been taken care of in the normal path, that is, hwpoison_user_mappings(), see [1][2]. Further more, for [3] to work correctly in the hugetlb repoisoning case, it's essential to inform VM the precise poisoned page, not the head page. [1] https://lkml.kernel.org/r/20231218135837.3310403-1-willy@infradead.org [2] https://lkml.kernel.org/r/20250224211445.2663312-1-jane.chu@oracle.com [3] https://lore.kernel.org/lkml/20251116013223.1557158-1-jiaqiyan@google.com/ Link: https://lkml.kernel.org/r/20260120232234.3462258-2-jane.chu@oracle.com Signed-off-by: Jane Chu Reviewed-by: Liam R. Howlett Acked-by: Miaohe Lin Cc: Chris Mason Cc: David Hildenbrand Cc: David Rientjes Cc: Jiaqi Yan Cc: Lorenzo Stoakes Cc: Matthew Wilcox (Oracle) Cc: Michal Hocko Cc: Mike Rapoport Cc: Muchun Song Cc: Naoya Horiguchi Cc: Oscar Salvador Cc: Suren Baghdasaryan Cc: William Roche Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

mm/memory-failure: fix missing ->mf_stats count in hugetlb poison

2026-02-06T15:55:46+00:00

commit a148a2040191b12b45b82cb29c281cb3036baf90 upstream. When a newly poisoned subpage ends up in an already poisoned hugetlb folio, 'num_poisoned_pages' is incremented, but the per node ->mf_stats is not. Fix the inconsistency by designating action_result() to update them both. While at it, define __get_huge_page_for_hwpoison() return values in terms of symbol names for better readibility. Also rename folio_set_hugetlb_hwpoison() to hugetlb_update_hwpoison() since the function does more than the conventional bit setting and the fact three possible return values are expected. Link: https://lkml.kernel.org/r/20260120232234.3462258-1-jane.chu@oracle.com Fixes: 18f41fa616ee ("mm: memory-failure: bump memory failure stats to pglist_data") Signed-off-by: Jane Chu Acked-by: Miaohe Lin Cc: Chris Mason Cc: David Hildenbrand Cc: David Rientjes Cc: Jiaqi Yan Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Matthew Wilcox (Oracle) Cc: Michal Hocko Cc: Mike Rapoport Cc: Muchun Song Cc: Naoya Horiguchi Cc: Oscar Salvador Cc: Suren Baghdasaryan Cc: William Roche Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

mm/memory-failure: fix redundant updates for already poisoned pages

2025-09-19T14:35:46+00:00

commit 3be306cccdccede13e3cefd0c14e430cc2b7c9c7 upstream. Duplicate memory errors can be reported by multiple sources. Passing an already poisoned page to action_result() causes issues: * The amount of hardware corrupted memory is incorrectly updated. * Per NUMA node MF stats are incorrectly updated. * Redundant "already poisoned" messages are printed. Avoid those issues by: * Skipping hardware corrupted memory updates for already poisoned pages. * Skipping per NUMA node MF stats updates for already poisoned pages. * Dropping redundant "already poisoned" messages. Make MF_MSG_ALREADY_POISONED consistent with other action_page_types and make calls to action_result() consistent for already poisoned normal pages and huge pages. Link: https://lkml.kernel.org/r/aLCiHMy12Ck3ouwC@hpe.com Fixes: b8b9488d50b7 ("mm/memory-failure: improve memory failure action_result messages") Signed-off-by: Kyle Meyer Reviewed-by: Jiaqi Yan Acked-by: David Hildenbrand Reviewed-by: Jane Chu Acked-by: Miaohe Lin Cc: Borislav Betkov Cc: Kyle Meyer Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: "Luck, Tony" Cc: Michal Hocko Cc: Mike Rapoport Cc: Naoya Horiguchi Cc: Oscar Salvador Cc: Russ Anderson Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

mm/memory-failure: fix VM_BUG_ON_PAGE(PagePoisoned(page)) when unpoison memory

2025-09-19T14:35:46+00:00

commit d613f53c83ec47089c4e25859d5e8e0359f6f8da upstream. When I did memory failure tests, below panic occurs: page dumped because: VM_BUG_ON_PAGE(PagePoisoned(page)) kernel BUG at include/linux/page-flags.h:616! Oops: invalid opcode: 0000 [#1] PREEMPT SMP NOPTI CPU: 3 PID: 720 Comm: bash Not tainted 6.10.0-rc1-00195-g148743902568 #40 RIP: 0010:unpoison_memory+0x2f3/0x590 RSP: 0018:ffffa57fc8787d60 EFLAGS: 00000246 RAX: 0000000000000037 RBX: 0000000000000009 RCX: ffff9be25fcdc9c8 RDX: 0000000000000000 RSI: 0000000000000027 RDI: ffff9be25fcdc9c0 RBP: 0000000000300000 R08: ffffffffb4956f88 R09: 0000000000009ffb R10: 0000000000000284 R11: ffffffffb4926fa0 R12: ffffe6b00c000000 R13: ffff9bdb453dfd00 R14: 0000000000000000 R15: fffffffffffffffe FS: 00007f08f04e4740(0000) GS:ffff9be25fcc0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000564787a30410 CR3: 000000010d4e2000 CR4: 00000000000006f0 Call Trace: unpoison_memory+0x2f3/0x590 simple_attr_write_xsigned.constprop.0.isra.0+0xb3/0x110 debugfs_attr_write+0x42/0x60 full_proxy_write+0x5b/0x80 vfs_write+0xd5/0x540 ksys_write+0x64/0xe0 do_syscall_64+0xb9/0x1d0 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f08f0314887 RSP: 002b:00007ffece710078 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000009 RCX: 00007f08f0314887 RDX: 0000000000000009 RSI: 0000564787a30410 RDI: 0000000000000001 RBP: 0000564787a30410 R08: 000000000000fefe R09: 000000007fffffff R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000009 R13: 00007f08f041b780 R14: 00007f08f0417600 R15: 00007f08f0416a00 Modules linked in: hwpoison_inject ---[ end trace 0000000000000000 ]--- RIP: 0010:unpoison_memory+0x2f3/0x590 RSP: 0018:ffffa57fc8787d60 EFLAGS: 00000246 RAX: 0000000000000037 RBX: 0000000000000009 RCX: ffff9be25fcdc9c8 RDX: 0000000000000000 RSI: 0000000000000027 RDI: ffff9be25fcdc9c0 RBP: 0000000000300000 R08: ffffffffb4956f88 R09: 0000000000009ffb R10: 0000000000000284 R11: ffffffffb4926fa0 R12: ffffe6b00c000000 R13: ffff9bdb453dfd00 R14: 0000000000000000 R15: fffffffffffffffe FS: 00007f08f04e4740(0000) GS:ffff9be25fcc0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000564787a30410 CR3: 000000010d4e2000 CR4: 00000000000006f0 Kernel panic - not syncing: Fatal exception Kernel Offset: 0x31c00000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) ---[ end Kernel panic - not syncing: Fatal exception ]--- The root cause is that unpoison_memory() tries to check the PG_HWPoison flags of an uninitialized page. So VM_BUG_ON_PAGE(PagePoisoned(page)) is triggered. This can be reproduced by below steps: 1.Offline memory block: echo offline > /sys/devices/system/memory/memory12/state 2.Get offlined memory pfn: page-types -b n -rlN 3.Write pfn to unpoison-pfn echo > /sys/kernel/debug/hwpoison/unpoison-pfn This scenario can be identified by pfn_to_online_page() returning NULL. And ZONE_DEVICE pages are never expected, so we can simply fail if pfn_to_online_page() == NULL to fix the bug. Link: https://lkml.kernel.org/r/20250828024618.1744895-1-linmiaohe@huawei.com Fixes: f1dd2cd13c4b ("mm, memory_hotplug: do not associate hotadded memory to zones until online") Signed-off-by: Miaohe Lin Suggested-by: David Hildenbrand Acked-by: David Hildenbrand Cc: Naoya Horiguchi Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

mm/memory-failure: fix infinite UCE for VM_PFNMAP pfn

2025-08-28T14:31:05+00:00

commit 2e6053fea379806269c4f7f5e36b523c9c0fb35c upstream. When memory_failure() is called for a already hwpoisoned pfn, kill_accessing_process() will be called to kill current task. However, if the vma of the accessing vaddr is VM_PFNMAP, walk_page_range() will skip the vma in walk_page_test() and return 0. Before commit aaf99ac2ceb7 ("mm/hwpoison: do not send SIGBUS to processes with recovered clean pages"), kill_accessing_process() will return EFAULT. For x86, the current task will be killed in kill_me_maybe(). However, after this commit, kill_accessing_process() simplies return 0, that means UCE is handled properly, but it doesn't actually. In such case, the user task will trigger UCE infinitely. To fix it, add .test_walk callback for hwpoison_walk_ops to scan all vmas. Link: https://lkml.kernel.org/r/20250815073209.1984582-1-tujinjiang@huawei.com Fixes: aaf99ac2ceb7 ("mm/hwpoison: do not send SIGBUS to processes with recovered clean pages") Signed-off-by: Jinjiang Tu Acked-by: David Hildenbrand Acked-by: Miaohe Lin Reviewed-by: Jane Chu Cc: Kefeng Wang Cc: Naoya Horiguchi Cc: Oscar Salvador Cc: Shuai Xue Cc: Zi Yan Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

mm/vmscan: fix hwpoisoned large folio handling in shrink_folio_list

2025-08-01T08:48:44+00:00

commit 9f1e8cd0b7c4c944e9921b52a6661b5eda2705ab upstream. In shrink_folio_list(), the hwpoisoned folio may be large folio, which can't be handled by unmap_poisoned_folio(). For THP, try_to_unmap_one() must be passed with TTU_SPLIT_HUGE_PMD to split huge PMD first and then retry. Without TTU_SPLIT_HUGE_PMD, we will trigger null-ptr deref of pvmw.pte. Even we passed TTU_SPLIT_HUGE_PMD, we will trigger a WARN_ON_ONCE due to the page isn't in swapcache. Since UCE is rare in real world, and race with reclaimation is more rare, just skipping the hwpoisoned large folio is enough. memory_failure() will handle it if the UCE is triggered again. This happens when memory reclaim for large folio races with memory_failure(), and will lead to kernel panic. The race is as follows: cpu0 cpu1 shrink_folio_list memory_failure TestSetPageHWPoison unmap_poisoned_folio --> trigger BUG_ON due to unmap_poisoned_folio couldn't handle large folio [tujinjiang@huawei.com: add comment to unmap_poisoned_folio()] Link: https://lkml.kernel.org/r/69fd4e00-1b13-d5f7-1c82-705c7d977ea4@huawei.com Link: https://lkml.kernel.org/r/20250627125747.3094074-2-tujinjiang@huawei.com Signed-off-by: Jinjiang Tu Fixes: 1b0449544c64 ("mm/vmscan: don't try to reclaim hwpoison folio") Reported-by: syzbot+3b220254df55d8ca8a61@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/68412d57.050a0220.2461cf.000e.GAE@google.com/ Acked-by: David Hildenbrand Reviewed-by: Miaohe Lin Acked-by: Zi Yan Reviewed-by: Oscar Salvador Cc: Kefeng Wang Cc: Michal Hocko Cc: Oscar Salvador Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

mm/hwpoison: do not send SIGBUS to processes with recovered clean pages

2025-04-20T08:15:49+00:00

commit aaf99ac2ceb7c974f758a635723eeaf48596388e upstream. When an uncorrected memory error is consumed there is a race between the CMCI from the memory controller reporting an uncorrected error with a UCNA signature, and the core reporting and SRAR signature machine check when the data is about to be consumed. - Background: why *UN*corrected errors tied to *C*MCI in Intel platform [1] Prior to Icelake memory controllers reported patrol scrub events that detected a previously unseen uncorrected error in memory by signaling a broadcast machine check with an SRAO (Software Recoverable Action Optional) signature in the machine check bank. This was overkill because it's not an urgent problem that no core is on the verge of consuming that bad data. It's also found that multi SRAO UCE may cause nested MCE interrupts and finally become an IERR. Hence, Intel downgrades the machine check bank signature of patrol scrub from SRAO to UCNA (Uncorrected, No Action required), and signal changed to #CMCI. Just to add to the confusion, Linux does take an action (in uc_decode_notifier()) to try to offline the page despite the UC*NA* signature name. - Background: why #CMCI and #MCE race when poison is consuming in Intel platform [1] Having decided that CMCI/UCNA is the best action for patrol scrub errors, the memory controller uses it for reads too. But the memory controller is executing asynchronously from the core, and can't tell the difference between a "real" read and a speculative read. So it will do CMCI/UCNA if an error is found in any read. Thus: 1) Core is clever and thinks address A is needed soon, issues a speculative read. 2) Core finds it is going to use address A soon after sending the read request 3) The CMCI from the memory controller is in a race with MCE from the core that will soon try to retire the load from address A. Quite often (because speculation has got better) the CMCI from the memory controller is delivered before the core is committed to the instruction reading address A, so the interrupt is taken, and Linux offlines the page (marking it as poison). - Why user process is killed for instr case Commit 046545a661af ("mm/hwpoison: fix error page recovered but reported "not recovered"") tries to fix noise message "Memory error not recovered" and skips duplicate SIGBUSs due to the race. But it also introduced a bug that kill_accessing_process() return -EHWPOISON for instr case, as result, kill_me_maybe() send a SIGBUS to user process. If the CMCI wins that race, the page is marked poisoned when uc_decode_notifier() calls memory_failure(). For dirty pages, memory_failure() invokes try_to_unmap() with the TTU_HWPOISON flag, converting the PTE to a hwpoison entry. As a result, kill_accessing_process(): - call walk_page_range() and return 1 regardless of whether try_to_unmap() succeeds or fails, - call kill_proc() to make sure a SIGBUS is sent - return -EHWPOISON to indicate that SIGBUS is already sent to the process and kill_me_maybe() doesn't have to send it again. However, for clean pages, the TTU_HWPOISON flag is cleared, leaving the PTE unchanged and not converted to a hwpoison entry. Conversely, for clean pages where PTE entries are not marked as hwpoison, kill_accessing_process() returns -EFAULT, causing kill_me_maybe() to send a SIGBUS. Console log looks like this: Memory failure: 0x827ca68: corrupted page was clean: dropped without side effects Memory failure: 0x827ca68: recovery action for clean LRU page: Recovered Memory failure: 0x827ca68: already hardware poisoned mce: Memory error not recovered To fix it, return 0 for "corrupted page was clean", preventing an unnecessary SIGBUS to user process. [1] https://lore.kernel.org/lkml/20250217063335.22257-1-xueshuai@linux.alibaba.com/T/#mba94f1305b3009dd340ce4114d3221fe810d1871 Link: https://lkml.kernel.org/r/20250312112852.82415-3-xueshuai@linux.alibaba.com Fixes: 046545a661af ("mm/hwpoison: fix error page recovered but reported "not recovered"") Signed-off-by: Shuai Xue Tested-by: Tony Luck Acked-by: Miaohe Lin Cc: Baolin Wang Cc: Borislav Betkov Cc: Catalin Marinas Cc: Dave Hansen Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Jane Chu Cc: Jarkko Sakkinen Cc: Jonathan Cameron Cc: Josh Poimboeuf Cc: Naoya Horiguchi Cc: Peter Zijlstra Cc: Ruidong Tian Cc: Thomas Gleinxer Cc: Yazen Ghannam Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

mm: memory-failure: update ttu flag inside unmap_poisoned_folio

2025-03-13T12:01:59+00:00

commit b81679b1633aa43c0d973adfa816d78c1ed0d032 upstream. Patch series "mm: memory_failure: unmap poisoned folio during migrate properly", v3. Fix two bugs during folio migration if the folio is poisoned. This patch (of 3): Commit 6da6b1d4a7df ("mm/hwpoison: convert TTU_IGNORE_HWPOISON to TTU_HWPOISON") introduce TTU_HWPOISON to replace TTU_IGNORE_HWPOISON in order to stop send SIGBUS signal when accessing an error page after a memory error on a clean folio. However during page migration, anon folio must be set with TTU_HWPOISON during unmap_*(). For pagecache we need some policy just like the one in hwpoison_user_mappings to set this flag. So move this policy from hwpoison_user_mappings to unmap_poisoned_folio to handle this warning properly. Warning will be produced during unamp poison folio with the following log: ------------[ cut here ]------------ WARNING: CPU: 1 PID: 365 at mm/rmap.c:1847 try_to_unmap_one+0x8fc/0xd3c Modules linked in: CPU: 1 UID: 0 PID: 365 Comm: bash Tainted: G W 6.13.0-rc1-00018-gacdb4bbda7ab #42 Tainted: [W]=WARN Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015 pstate: 20400005 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : try_to_unmap_one+0x8fc/0xd3c lr : try_to_unmap_one+0x3dc/0xd3c Call trace: try_to_unmap_one+0x8fc/0xd3c (P) try_to_unmap_one+0x3dc/0xd3c (L) rmap_walk_anon+0xdc/0x1f8 rmap_walk+0x3c/0x58 try_to_unmap+0x88/0x90 unmap_poisoned_folio+0x30/0xa8 do_migrate_range+0x4a0/0x568 offline_pages+0x5a4/0x670 memory_block_action+0x17c/0x374 memory_subsys_offline+0x3c/0x78 device_offline+0xa4/0xd0 state_store+0x8c/0xf0 dev_attr_store+0x18/0x2c sysfs_kf_write+0x44/0x54 kernfs_fop_write_iter+0x118/0x1a8 vfs_write+0x3a8/0x4bc ksys_write+0x6c/0xf8 __arm64_sys_write+0x1c/0x28 invoke_syscall+0x44/0x100 el0_svc_common.constprop.0+0x40/0xe0 do_el0_svc+0x1c/0x28 el0_svc+0x30/0xd0 el0t_64_sync_handler+0xc8/0xcc el0t_64_sync+0x198/0x19c ---[ end trace 0000000000000000 ]--- [mawupeng1@huawei.com: unmap_poisoned_folio(): remove shadowed local `mapping', per Miaohe] Link: https://lkml.kernel.org/r/20250219060653.3849083-1-mawupeng1@huawei.com Link: https://lkml.kernel.org/r/20250217014329.3610326-1-mawupeng1@huawei.com Link: https://lkml.kernel.org/r/20250217014329.3610326-2-mawupeng1@huawei.com Fixes: 6da6b1d4a7df ("mm/hwpoison: convert TTU_IGNORE_HWPOISON to TTU_HWPOISON") Signed-off-by: Ma Wupeng Suggested-by: David Hildenbrand Acked-by: David Hildenbrand Acked-by: Miaohe Lin Cc: Ma Wupeng Cc: Michal Hocko Cc: Naoya Horiguchi Cc: Oscar Salvador Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

mm: migrate: add isolate_folio_to_list()

2024-09-04T04:15:59+00:00

Add isolate_folio_to_list() helper to try to isolate HugeTLB, no-LRU movable and LRU folios to a list, which will be reused by do_migrate_range() from memory hotplug soon, also drop the mf_isolate_folio() since we could directly use new helper in the soft_offline_in_use_page(). Link: https://lkml.kernel.org/r/20240827114728.3212578-5-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Acked-by: David Hildenbrand Acked-by: Miaohe Lin Tested-by: Miaohe Lin Cc: Dan Carpenter Cc: Jonathan Cameron Cc: Naoya Horiguchi Cc: Oscar Salvador Signed-off-by: Andrew Morton

mm: memory-failure: add unmap_poisoned_folio()

2024-09-04T04:15:59+00:00

Add unmap_poisoned_folio() helper which will be reused by do_migrate_range() from memory hotplug soon. [akpm@linux-foundation.org: whitespace tweak, per Miaohe Lin] Link: https://lkml.kernel.org/r/1f80c7e3-c30d-1ac1-6a36-d1a5f5907f7c@huawei.com Link: https://lkml.kernel.org/r/20240827114728.3212578-3-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Acked-by: David Hildenbrand Acked-by: Miaohe Lin Cc: Dan Carpenter Cc: Jonathan Cameron Cc: Naoya Horiguchi Cc: Oscar Salvador Signed-off-by: Andrew Morton