It's unexpected to walk the page table when vma_address() return -EFAULT.
But dev_pagemap_mapping_shift() is called only when vma associated to the
error page is found already in collect_procs_{file,anon}, so vma_address()
should not return -EFAULT except with some bug, as Naoya pointed out. We
can use VM_BUG_ON_VMA() to catch this bug here.
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Acked-by: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
---
mm/memory-failure.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index b3ff7e99a421..eaa241058401 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -315,6 +315,7 @@ static unsigned long dev_pagemap_mapping_shift(struct page *page,
pmd_t *pmd;
pte_t *pte;
+ VM_BUG_ON_VMA(address == -EFAULT, vma);
pgd = pgd_offset(vma->vm_mm, address);
if (!pgd_present(*pgd))
return 0;
--
2.23.0
