From 5c91c0e77b8f2681e2b269c8abb4c5acef434d5b Mon Sep 17 00:00:00 2001 From: Qi Zheng 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 Reviewed-by: David Hildenbrand Cc: Naoya Horiguchi Cc: Muchun Song Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- 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 41901c7..3e6449f 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; } /* -- 2.7.4