6.6-stable review patch. If anyone has any objections, please let me know.
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From: Jinjiang Tu tujinjiang@huawei.com
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 tujinjiang@huawei.com Acked-by: David Hildenbrand david@redhat.com Acked-by: Miaohe Lin linmiaohe@huawei.com Reviewed-by: Jane Chu jane.chu@oracle.com Cc: Kefeng Wang wangkefeng.wang@huawei.com Cc: Naoya Horiguchi nao.horiguchi@gmail.com Cc: Oscar Salvador osalvador@suse.de Cc: Shuai Xue xueshuai@linux.alibaba.com Cc: Zi Yan ziy@nvidia.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- mm/memory-failure.c | 8 ++++++++ 1 file changed, 8 insertions(+)
--- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -835,9 +835,17 @@ static int hwpoison_hugetlb_range(pte_t #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, };