From: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx> Subject: 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. Davidsaid "I guess this code never runs on 32bit / highmem, that's why we didn't notice so far". [akpm@xxxxxxxxxxxxxxxxxxxx: cleanup] Link: https://lkml.kernel.org/r/20210923122642.4999-1-zhengqi.arch@xxxxxxxxxxxxx Signed-off-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx> Reviewed-by: David Hildenbrand <david@xxxxxxxxxx> Cc: Naoya Horiguchi <naoya.horiguchi@xxxxxxx> Cc: Muchun Song <songmuchun@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/memory-failure.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) --- a/mm/memory-failure.c~mm-memory_failure-fix-the-missing-pte_unmap-call +++ a/mm/memory-failure.c @@ -306,6 +306,7 @@ static unsigned long dev_pagemap_mapping 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 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; } /* _
