From 5c91c0e77b8f2681e2b269c8abb4c5acef434d5b Mon Sep 17 00:00:00 2001
From: Qi Zheng <zhengqi.arch@bytedance.com>
Date: Fri, 24 Sep 2021 15:44:03 -0700
Subject: [PATCH] mm/memory_failure: fix the missing pte_unmap() call
The paired pte_unmap() call is missing before the
dev_pagemap_mapping_shift() returns. So fix it.
David says:
"I guess this code never runs on 32bit / highmem, that's why we didn't
notice so far".
[akpm@linux-foundation.org: cleanup]
Link: https://lkml.kernel.org/r/20210923122642.4999-1-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
mm/memory-failure.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 41901c7bb58f..3e6449f2102a 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -306,6 +306,7 @@ static unsigned long dev_pagemap_mapping_shift(struct page *page,
struct vm_area_struct *vma)
{
unsigned long address = vma_address(page, vma);
+ unsigned long ret = 0;
pgd_t *pgd;
p4d_t *p4d;
pud_t *pud;
@@ -329,11 +330,10 @@ static unsigned long dev_pagemap_mapping_shift(struct page *page,
if (pmd_devmap(*pmd))
return PMD_SHIFT;
pte = pte_offset_map(pmd, address);
- if (!pte_present(*pte))
- return 0;
- if (pte_devmap(*pte))
- return PAGE_SHIFT;
- return 0;
+ if (pte_present(*pte) && pte_devmap(*pte))
+ ret = PAGE_SHIFT;
+ pte_unmap(pte);
+ return ret;
}
/*