From 3bd634140e6623551d36b0995cbb827bcbdf4216 Mon Sep 17 00:00:00 2001 From: Jinjiang Tu Date: Fri, 15 Aug 2025 15:32:09 +0800 Subject: [PATCH] mm/memory-failure: fix infinite UCE for VM_PFNMAP pfn ANBZ: #24330 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: Ruidong Tian --- mm/memory-failure.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 866d1ab1c600..14a61a63350f 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -836,9 +836,17 @@ static int hwpoison_hugetlb_range(pte_t *ptep, unsigned long hmask, #define hwpoison_hugetlb_range NULL #endif +static int hwpoison_test_walk(unsigned long start, unsigned long end, + struct mm_walk *walk) +{ + /* We also want to consider pages mapped into VM_PFNMAP. */ + return 0; +} + static const struct mm_walk_ops hwpoison_walk_ops = { .pmd_entry = hwpoison_pte_range, .hugetlb_entry = hwpoison_hugetlb_range, + .test_walk = hwpoison_test_walk, .walk_lock = PGWALK_RDLOCK, }; -- Gitee