kernel/linux.git/mm/memory-failure.c, branch v5.15.208

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

2025-10-02T11:39:05+00:00

[ Upstream commit d613f53c83ec47089c4e25859d5e8e0359f6f8da ] 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 [ Adjust context ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

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

2025-08-28T14:24:37+00:00

[ Upstream commit 2e6053fea379806269c4f7f5e36b523c9c0fb35c ] 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 [ Adjust context ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

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

2025-05-02T05:44:04+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/huge_memory: don't unpoison huge_zero_folio

2024-07-05T07:14:22+00:00

commit fe6f86f4b40855a130a19aa589f9ba7f650423f4 upstream. When I did memory failure tests recently, below panic occurs: kernel BUG at include/linux/mm.h:1135! invalid opcode: 0000 [#1] PREEMPT SMP NOPTI CPU: 9 PID: 137 Comm: kswapd1 Not tainted 6.9.0-rc4-00491-gd5ce28f156fe-dirty #14 RIP: 0010:shrink_huge_zero_page_scan+0x168/0x1a0 RSP: 0018:ffff9933c6c57bd0 EFLAGS: 00000246 RAX: 000000000000003e RBX: 0000000000000000 RCX: ffff88f61fc5c9c8 RDX: 0000000000000000 RSI: 0000000000000027 RDI: ffff88f61fc5c9c0 RBP: ffffcd7c446b0000 R08: ffffffff9a9405f0 R09: 0000000000005492 R10: 00000000000030ea R11: ffffffff9a9405f0 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: ffff88e703c4ac00 FS: 0000000000000000(0000) GS:ffff88f61fc40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055f4da6e9878 CR3: 0000000c71048000 CR4: 00000000000006f0 Call Trace: do_shrink_slab+0x14f/0x6a0 shrink_slab+0xca/0x8c0 shrink_node+0x2d0/0x7d0 balance_pgdat+0x33a/0x720 kswapd+0x1f3/0x410 kthread+0xd5/0x100 ret_from_fork+0x2f/0x50 ret_from_fork_asm+0x1a/0x30 Modules linked in: mce_inject hwpoison_inject ---[ end trace 0000000000000000 ]--- RIP: 0010:shrink_huge_zero_page_scan+0x168/0x1a0 RSP: 0018:ffff9933c6c57bd0 EFLAGS: 00000246 RAX: 000000000000003e RBX: 0000000000000000 RCX: ffff88f61fc5c9c8 RDX: 0000000000000000 RSI: 0000000000000027 RDI: ffff88f61fc5c9c0 RBP: ffffcd7c446b0000 R08: ffffffff9a9405f0 R09: 0000000000005492 R10: 00000000000030ea R11: ffffffff9a9405f0 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: ffff88e703c4ac00 FS: 0000000000000000(0000) GS:ffff88f61fc40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055f4da6e9878 CR3: 0000000c71048000 CR4: 00000000000006f0 The root cause is that HWPoison flag will be set for huge_zero_folio without increasing the folio refcnt. But then unpoison_memory() will decrease the folio refcnt unexpectedly as it appears like a successfully hwpoisoned folio leading to VM_BUG_ON_PAGE(page_ref_count(page) == 0) when releasing huge_zero_folio. Skip unpoisoning huge_zero_folio in unpoison_memory() to fix this issue. We're not prepared to unpoison huge_zero_folio yet. Link: https://lkml.kernel.org/r/20240516122608.22610-1-linmiaohe@huawei.com Fixes: 478d134e9506 ("mm/huge_memory: do not overkill when splitting huge_zero_page") Signed-off-by: Miaohe Lin Acked-by: David Hildenbrand Reviewed-by: Yang Shi Reviewed-by: Oscar Salvador Reviewed-by: Anshuman Khandual Cc: Naoya Horiguchi Cc: Xu Yu Cc: Signed-off-by: Andrew Morton Signed-off-by: Miaohe Lin Signed-off-by: Greg Kroah-Hartman

mm/memory-failure: check the mapcount of the precise page

2024-01-15T17:51:21+00:00

[ Upstream commit c79c5a0a00a9457718056b588f312baadf44e471 ] A process may map only some of the pages in a folio, and might be missed if it maps the poisoned page but not the head page. Or it might be unnecessarily hit if it maps the head page, but not the poisoned page. Link: https://lkml.kernel.org/r/20231218135837.3310403-3-willy@infradead.org Fixes: 7af446a841a2 ("HWPOISON, hugetlb: enable error handling path for hugepage") Signed-off-by: Matthew Wilcox (Oracle) Cc: Dan Williams Cc: Naoya Horiguchi Cc: Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin

mm: memory-failure: fix unexpected return value in soft_offline_page()

2023-08-30T14:18:21+00:00

[ Upstream commit e2c1ab070fdc81010ec44634838d24fce9ff9e53 ] When page_handle_poison() fails to handle the hugepage or free page in retry path, soft_offline_page() will return 0 while -EBUSY is expected in this case. Consequently the user will think soft_offline_page succeeds while it in fact failed. So the user will not try again later in this case. Link: https://lkml.kernel.org/r/20230627112808.1275241-1-linmiaohe@huawei.com Fixes: b94e02822deb ("mm,hwpoison: try to narrow window race for free pages") Signed-off-by: Miaohe Lin Acked-by: Naoya Horiguchi Cc: Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin

mm: memory-failure: kill soft_offline_free_page()

2023-08-30T14:18:21+00:00

[ Upstream commit 7adb45887c8af88985c335b53d253654e9d2dd16 ] Open-code the page_handle_poison() into soft_offline_page() and kill unneeded soft_offline_free_page(). Link: https://lkml.kernel.org/r/20220819033402.156519-1-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Reviewed-by: Miaohe Lin Acked-by: Naoya Horiguchi Signed-off-by: Andrew Morton Stable-dep-of: e2c1ab070fdc ("mm: memory-failure: fix unexpected return value in soft_offline_page()") Signed-off-by: Sasha Levin

mm/migration: return errno when isolate_huge_page failed

2023-02-14T18:17:56+00:00

[ Upstream commit 7ce82f4c3f3ead13a9d9498768e3b1a79975c4d8 ] We might fail to isolate huge page due to e.g. the page is under migration which cleared HPageMigratable. We should return errno in this case rather than always return 1 which could confuse the user, i.e. the caller might think all of the memory is migrated while the hugetlb page is left behind. We make the prototype of isolate_huge_page consistent with isolate_lru_page as suggested by Huang Ying and rename isolate_huge_page to isolate_hugetlb as suggested by Muchun to improve the readability. Link: https://lkml.kernel.org/r/20220530113016.16663-4-linmiaohe@huawei.com Fixes: e8db67eb0ded ("mm: migrate: move_pages() supports thp migration") Signed-off-by: Miaohe Lin Suggested-by: Huang Ying Reported-by: kernel test robot (build error) Cc: Alistair Popple Cc: Christoph Hellwig Cc: Christoph Lameter Cc: David Hildenbrand Cc: David Howells Cc: Mike Kravetz Cc: Muchun Song Cc: Oscar Salvador Cc: Peter Xu Signed-off-by: Andrew Morton Stable-dep-of: 73bdf65ea748 ("migrate: hugetlb: check for hugetlb shared PMD in node migration") Signed-off-by: Sasha Levin

hugetlbfs: don't delete error page from pagecache

2022-11-26T08:24:33+00:00

[ Upstream commit 8625147cafaa9ba74713d682f5185eb62cb2aedb ] This change is very similar to the change that was made for shmem [1], and it solves the same problem but for HugeTLBFS instead. Currently, when poison is found in a HugeTLB page, the page is removed from the page cache. That means that attempting to map or read that hugepage in the future will result in a new hugepage being allocated instead of notifying the user that the page was poisoned. As [1] states, this is effectively memory corruption. The fix is to leave the page in the page cache. If the user attempts to use a poisoned HugeTLB page with a syscall, the syscall will fail with EIO, the same error code that shmem uses. For attempts to map the page, the thread will get a BUS_MCEERR_AR SIGBUS. [1]: commit a76054266661 ("mm: shmem: don't truncate page if memory failure happens") Link: https://lkml.kernel.org/r/20221018200125.848471-1-jthoughton@google.com Signed-off-by: James Houghton Reviewed-by: Mike Kravetz Reviewed-by: Naoya Horiguchi Tested-by: Naoya Horiguchi Reviewed-by: Yang Shi Cc: Axel Rasmussen Cc: James Houghton Cc: Miaohe Lin Cc: Muchun Song Cc: Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin

mm: shmem: don't truncate page if memory failure happens

2022-11-26T08:24:28+00:00

commit a7605426666196c5a460dd3de6f8dac1d3c21f00 upstream. The current behavior of memory failure is to truncate the page cache regardless of dirty or clean. If the page is dirty the later access will get the obsolete data from disk without any notification to the users. This may cause silent data loss. It is even worse for shmem since shmem is in-memory filesystem, truncating page cache means discarding data blocks. The later read would return all zero. The right approach is to keep the corrupted page in page cache, any later access would return error for syscalls or SIGBUS for page fault, until the file is truncated, hole punched or removed. The regular storage backed filesystems would be more complicated so this patch is focused on shmem. This also unblock the support for soft offlining shmem THP. [akpm@linux-foundation.org: coding style fixes] [arnd@arndb.de: fix uninitialized variable use in me_pagecache_clean()] Link: https://lkml.kernel.org/r/20211022064748.4173718-1-arnd@kernel.org [Fix invalid pointer dereference in shmem_read_mapping_page_gfp() with a slight different implementation from what Ajay Garg and Muchun Song proposed and reworked the error handling of shmem_write_begin() suggested by Linus] Link: https://lore.kernel.org/linux-mm/20211111084617.6746-1-ajaygargnsit@gmail.com/ Link: https://lkml.kernel.org/r/20211020210755.23964-6-shy828301@gmail.com Link: https://lkml.kernel.org/r/20211116193247.21102-1-shy828301@gmail.com Signed-off-by: Yang Shi Signed-off-by: Arnd Bergmann Cc: Hugh Dickins Cc: Kirill A. Shutemov Cc: Matthew Wilcox Cc: Naoya Horiguchi Cc: Oscar Salvador Cc: Peter Xu Cc: Ajay Garg Cc: Muchun Song Cc: Andy Lavr Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Cc: Naoya Horiguchi Signed-off-by: Greg Kroah-Hartman