Messages in this thread Patch in this message | | | From | Punit Agrawal <> | Subject | [PATCH 1/3] arm64: hugetlb: Fix huge_pte_offset to return poisoned page table entries | Date | Wed, 12 Apr 2017 15:04:57 +0100 |
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When memory failure is enabled, a poisoned hugepage pte is marked as a swap entry. huge_pte_offset() does not return the poisoned page table entries when it encounters PUD/PMD hugepages.
This behaviour of huge_pte_offset() leads to error such as below when munmap is called on poisoned hugepages.
[ 344.165544] mm/pgtable-generic.c:33: bad pmd 000000083af00074.
Fix huge_pte_offset() to return the poisoned pte which is then appropriately handled by the generic layer code.
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Steve Capper <steve.capper@arm.com> Cc: David Woods <dwoods@mellanox.com> --- arch/arm64/mm/hugetlbpage.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-)
diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c index 7514a000e361..5f1832165d69 100644 --- a/arch/arm64/mm/hugetlbpage.c +++ b/arch/arm64/mm/hugetlbpage.c @@ -143,15 +143,24 @@ pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr) pr_debug("%s: addr:0x%lx pgd:%p\n", __func__, addr, pgd); if (!pgd_present(*pgd)) return NULL; - pud = pud_offset(pgd, addr); - if (!pud_present(*pud)) - return NULL; - if (pud_huge(*pud)) + pud = pud_offset(pgd, addr); + /* + * In case of HW Poisoning, a hugepage pud/pmd can contain + * poisoned entries. Poisoned entries are marked as swap + * entries. + * + * For puds/pmds that are not present, check to see if it + * could be a swap entry (!present and !none). + */ + if ((!pte_present(pud_pte(*pud)) && !pud_none(*pud)) || pud_huge(*pud)) return (pte_t *)pud; + pmd = pmd_offset(pud, addr); - if (!pmd_present(*pmd)) + if (pmd_none(*pmd)) return NULL; + if (!pmd_present(*pmd) && !pmd_none(*pmd)) + return (pte_t *)pmd; if (pte_cont(pmd_pte(*pmd))) { pmd = pmd_offset( @@ -160,6 +169,7 @@ pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr) } if (pmd_huge(*pmd)) return (pte_t *)pmd; + pte = pte_offset_kernel(pmd, addr); if (pte_present(*pte) && pte_cont(*pte)) { pte = pte_offset_kernel( -- 2.11.0
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