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

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commit 2e6053fea3 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 aaf99ac2ce ("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: aaf99ac2ce ("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>
This commit is contained in:
Jinjiang Tu 2025-08-15 15:32:09 +08:00 committed by Greg Kroah-Hartman
parent 61a9f2e5c4
commit 8e2b8a3079
1 changed files with 8 additions and 0 deletions
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8
mm/memory-failure.c
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@ -845,9 +845,17 @@ 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,
};