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

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
......@@ -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;
......
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