The patch titled Subject: mm/memory-failure: fix infinite UCE for VM_PFNMAP pfn has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-memory-failure-fix-infinite-uce-for-vm_pfnmap-pfn.patch
This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...
This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------ From: Jinjiang Tu tujinjiang@huawei.com Subject: mm/memory-failure: fix infinite UCE for VM_PFNMAP pfn Date: Fri, 15 Aug 2025 15:32:09 +0800
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 ---
mm/memory-failure.c | 8 ++++++++ 1 file changed, 8 insertions(+)
--- a/mm/memory-failure.c~mm-memory-failure-fix-infinite-uce-for-vm_pfnmap-pfn +++ a/mm/memory-failure.c @@ -853,9 +853,17 @@ 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, };
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Patches currently in -mm which might be from tujinjiang@huawei.com are
mm-memory-failure-fix-infinite-uce-for-vm_pfnmap-pfn.patch mm-memory_hotplug-fix-hwpoisoned-large-folio-handling-in-do_migrate_range.patch