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SubjectRe: [PATCH] mm/memory_failure: Fix the missing pte_unmap() call
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On 23.09.21 14:26, Qi Zheng wrote:
> The paired pte_unmap() call is missing before the
> dev_pagemap_mapping_shift() returns. So fix it.
>
> Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
> ---
> mm/memory-failure.c | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index e2984c123e7e..4e5419f16fd4 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;
> @@ -330,10 +331,12 @@ static unsigned long dev_pagemap_mapping_shift(struct page *page,
> return PMD_SHIFT;
> pte = pte_offset_map(pmd, address);
> if (!pte_present(*pte))
> - return 0;
> + goto unmap;
> if (pte_devmap(*pte))
> - return PAGE_SHIFT;
> - return 0;
> + ret = PAGE_SHIFT;
> +unmap:
> + pte_unmap(pte);
> + return ret;
> }
>
> /*
>

I guess this code never runs on 32bit / highmem, that's why we didn't
notice so far.

Reviewed-by: David Hildenbrand <david@redhat.com>

--
Thanks,

David / dhildenb

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