Commit ea3732f7 authored by Miaohe Lin's avatar Miaohe Lin Committed by Linus Torvalds
Browse files

mm/hwpoison: fix potential pte_unmap_unlock pte error 

If the first pte is equal to poisoned_pfn, i.e.  check_hwpoisoned_entry()
return 1, the wrong ptep - 1 would be passed to pte_unmap_unlock().

Link: https://lkml.kernel.org/r/20210814105131.48814-3-linmiaohe@huawei.com


Fixes: ad9c59c24095 ("mm,hwpoison: send SIGBUS with error virutal address")
Signed-off-by: default avatarMiaohe Lin <linmiaohe@huawei.com>
Acked-by: default avatarNaoya Horiguchi <naoya.horiguchi@nec.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent ae611d07

mm/memory-failure.c

+4 −3
Original line number Diff line number Diff line
@@ -632,7 +632,7 @@ static int hwpoison_pte_range(pmd_t *pmdp, unsigned long addr, 
{

	struct hwp_walk *hwp = (struct hwp_walk *)walk->private;

	int ret = 0;

	pte_t *ptep;

	pte_t *ptep, *mapped_pte;

	spinlock_t *ptl;



	ptl = pmd_trans_huge_lock(pmdp, walk->vma);
@@ -645,14 +645,15 @@ static int hwpoison_pte_range(pmd_t *pmdp, unsigned long addr, 
	if (pmd_trans_unstable(pmdp))

		goto out;



	ptep = pte_offset_map_lock(walk->vma->vm_mm, pmdp, addr, &ptl);

	mapped_pte = ptep = pte_offset_map_lock(walk->vma->vm_mm, pmdp,

						addr, &ptl);

	for (; addr != end; ptep++, addr += PAGE_SIZE) {

		ret = check_hwpoisoned_entry(*ptep, addr, PAGE_SHIFT,

					     hwp->pfn, &hwp->tk);

		if (ret == 1)

			break;

	}

	pte_unmap_unlock(ptep - 1, ptl);

	pte_unmap_unlock(mapped_pte, ptl);

out:

	cond_resched();

	return ret;