Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754864AbdDNT3w (ORCPT ); Fri, 14 Apr 2017 15:29:52 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:60670 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753329AbdDNT3p (ORCPT ); Fri, 14 Apr 2017 15:29:45 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 4EDBA60D35 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=tbaicar@codeaurora.org Subject: Re: [PATCH 1/3] arm64: hugetlb: Fix huge_pte_offset to return poisoned page table entries To: Punit Agrawal , catalin.marinas@arm.com, will.deacon@arm.com Cc: linux-arm-kernel@lists.infradead.org, steve.capper@arm.com, linux-kernel@vger.kernel.org, David Woods References: <20170412140459.21824-1-punit.agrawal@arm.com> <20170412140459.21824-2-punit.agrawal@arm.com> From: "Baicar, Tyler" Message-ID: Date: Fri, 14 Apr 2017 13:29:42 -0600 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.0.1 MIME-Version: 1.0 In-Reply-To: <20170412140459.21824-2-punit.agrawal@arm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2532 Lines: 72 On 4/12/2017 8:04 AM, Punit Agrawal wrote: > 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 Tested-by: Tyler Baicar Thanks, Tyler > --- > 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( -- Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.