From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754274AbdDLOFV (ORCPT ); Wed, 12 Apr 2017 10:05:21 -0400 Received: from foss.arm.com ([217.140.101.70]:44682 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752695AbdDLOFQ (ORCPT ); Wed, 12 Apr 2017 10:05:16 -0400 From: Punit Agrawal To: catalin.marinas@arm.com, will.deacon@arm.com Cc: Punit Agrawal , tbaicar@codeaurora.org, linux-arm-kernel@lists.infradead.org, steve.capper@arm.com, linux-kernel@vger.kernel.org, David Woods 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 Message-Id: <20170412140459.21824-2-punit.agrawal@arm.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170412140459.21824-1-punit.agrawal@arm.com> References: <20170412140459.21824-1-punit.agrawal@arm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 Cc: Catalin Marinas Cc: Steve Capper Cc: David Woods --- 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 From mboxrd@z Thu Jan 1 00:00:00 1970 From: punit.agrawal@arm.com (Punit Agrawal) Date: Wed, 12 Apr 2017 15:04:57 +0100 Subject: [PATCH 1/3] arm64: hugetlb: Fix huge_pte_offset to return poisoned page table entries In-Reply-To: <20170412140459.21824-1-punit.agrawal@arm.com> References: <20170412140459.21824-1-punit.agrawal@arm.com> Message-ID: <20170412140459.21824-2-punit.agrawal@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 Cc: Catalin Marinas Cc: Steve Capper Cc: David Woods --- 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