6.12-stable review patch. If anyone has any objections, please let me know.
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From: Ma Wupeng mawupeng1@huawei.com
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 mawupeng1@huawei.com Suggested-by: David Hildenbrand david@redhat.com Acked-by: David Hildenbrand david@redhat.com Acked-by: Miaohe Lin linmiaohe@huawei.com Cc: Ma Wupeng mawupeng1@huawei.com Cc: Michal Hocko mhocko@suse.com Cc: Naoya Horiguchi nao.horiguchi@gmail.com Cc: Oscar Salvador osalvador@suse.de Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- mm/internal.h | 5 ++-- mm/memory-failure.c | 63 +++++++++++++++++++++++++--------------------------- mm/memory_hotplug.c | 3 +- 3 files changed, 36 insertions(+), 35 deletions(-)
--- a/mm/internal.h +++ b/mm/internal.h @@ -1101,7 +1101,7 @@ static inline int find_next_best_node(in * mm/memory-failure.c */ #ifdef CONFIG_MEMORY_FAILURE -void unmap_poisoned_folio(struct folio *folio, enum ttu_flags ttu); +int unmap_poisoned_folio(struct folio *folio, unsigned long pfn, bool must_kill); void shake_folio(struct folio *folio); extern int hwpoison_filter(struct page *p);
@@ -1123,8 +1123,9 @@ void add_to_kill_ksm(struct task_struct unsigned long page_mapped_in_vma(struct page *page, struct vm_area_struct *vma);
#else -static inline void unmap_poisoned_folio(struct folio *folio, enum ttu_flags ttu) +static inline int unmap_poisoned_folio(struct folio *folio, unsigned long pfn, bool must_kill) { + return -EBUSY; } #endif
--- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1554,11 +1554,35 @@ static int get_hwpoison_page(struct page return ret; }
-void unmap_poisoned_folio(struct folio *folio, enum ttu_flags ttu) +int unmap_poisoned_folio(struct folio *folio, unsigned long pfn, bool must_kill) { - if (folio_test_hugetlb(folio) && !folio_test_anon(folio)) { - struct address_space *mapping; + enum ttu_flags ttu = TTU_IGNORE_MLOCK | TTU_SYNC | TTU_HWPOISON; + struct address_space *mapping; + + if (folio_test_swapcache(folio)) { + pr_err("%#lx: keeping poisoned page in swap cache\n", pfn); + ttu &= ~TTU_HWPOISON; + } + + /* + * Propagate the dirty bit from PTEs to struct page first, because we + * need this to decide if we should kill or just drop the page. + * XXX: the dirty test could be racy: set_page_dirty() may not always + * be called inside page lock (it's recommended but not enforced). + */ + mapping = folio_mapping(folio); + if (!must_kill && !folio_test_dirty(folio) && mapping && + mapping_can_writeback(mapping)) { + if (folio_mkclean(folio)) { + folio_set_dirty(folio); + } else { + ttu &= ~TTU_HWPOISON; + pr_info("%#lx: corrupted page was clean: dropped without side effects\n", + pfn); + } + }
+ if (folio_test_hugetlb(folio) && !folio_test_anon(folio)) { /* * For hugetlb folios in shared mappings, try_to_unmap * could potentially call huge_pmd_unshare. Because of @@ -1570,7 +1594,7 @@ void unmap_poisoned_folio(struct folio * if (!mapping) { pr_info("%#lx: could not lock mapping for mapped hugetlb folio\n", folio_pfn(folio)); - return; + return -EBUSY; }
try_to_unmap(folio, ttu|TTU_RMAP_LOCKED); @@ -1578,6 +1602,8 @@ void unmap_poisoned_folio(struct folio * } else { try_to_unmap(folio, ttu); } + + return folio_mapped(folio) ? -EBUSY : 0; }
/* @@ -1587,8 +1613,6 @@ void unmap_poisoned_folio(struct folio * static bool hwpoison_user_mappings(struct folio *folio, struct page *p, unsigned long pfn, int flags) { - enum ttu_flags ttu = TTU_IGNORE_MLOCK | TTU_SYNC | TTU_HWPOISON; - struct address_space *mapping; LIST_HEAD(tokill); bool unmap_success; int forcekill; @@ -1611,29 +1635,6 @@ static bool hwpoison_user_mappings(struc if (!folio_mapped(folio)) return true;
- if (folio_test_swapcache(folio)) { - pr_err("%#lx: keeping poisoned page in swap cache\n", pfn); - ttu &= ~TTU_HWPOISON; - } - - /* - * Propagate the dirty bit from PTEs to struct page first, because we - * need this to decide if we should kill or just drop the page. - * XXX: the dirty test could be racy: set_page_dirty() may not always - * be called inside page lock (it's recommended but not enforced). - */ - mapping = folio_mapping(folio); - if (!(flags & MF_MUST_KILL) && !folio_test_dirty(folio) && mapping && - mapping_can_writeback(mapping)) { - if (folio_mkclean(folio)) { - folio_set_dirty(folio); - } else { - ttu &= ~TTU_HWPOISON; - pr_info("%#lx: corrupted page was clean: dropped without side effects\n", - pfn); - } - } - /* * First collect all the processes that have the page * mapped in dirty form. This has to be done before try_to_unmap, @@ -1641,9 +1642,7 @@ static bool hwpoison_user_mappings(struc */ collect_procs(folio, p, &tokill, flags & MF_ACTION_REQUIRED);
- unmap_poisoned_folio(folio, ttu); - - unmap_success = !folio_mapped(folio); + unmap_success = !unmap_poisoned_folio(folio, pfn, flags & MF_MUST_KILL); if (!unmap_success) pr_err("%#lx: failed to unmap page (folio mapcount=%d)\n", pfn, folio_mapcount(folio)); --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1806,7 +1806,8 @@ static void do_migrate_range(unsigned lo if (WARN_ON(folio_test_lru(folio))) folio_isolate_lru(folio); if (folio_mapped(folio)) - unmap_poisoned_folio(folio, TTU_IGNORE_MLOCK); + unmap_poisoned_folio(folio, pfn, false); + continue; }