From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f198.google.com (mail-pf0-f198.google.com [209.85.192.198]) by kanga.kvack.org (Postfix) with ESMTP id 1B8246B039F for ; Wed, 5 Apr 2017 09:38:05 -0400 (EDT) Received: by mail-pf0-f198.google.com with SMTP id y62so6653372pfd.17 for ; Wed, 05 Apr 2017 06:38:05 -0700 (PDT) Received: from foss.arm.com (foss.arm.com. [217.140.101.70]) by mx.google.com with ESMTP id z63si20673293pfz.321.2017.04.05.06.38.03 for ; Wed, 05 Apr 2017 06:38:04 -0700 (PDT) From: Punit Agrawal Subject: [PATCH v2 2/9] arm64: hugetlbpages: Support handling swap entries in huge_pte_offset() Date: Wed, 5 Apr 2017 14:37:15 +0100 Message-Id: <20170405133722.6406-3-punit.agrawal@arm.com> In-Reply-To: <20170405133722.6406-1-punit.agrawal@arm.com> References: <20170405133722.6406-1-punit.agrawal@arm.com> Sender: owner-linux-mm@kvack.org List-ID: To: catalin.marinas@arm.com, will.deacon@arm.com, akpm@linux-foundation.org, mark.rutland@arm.com Cc: Punit Agrawal , linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, tbaicar@codeaurora.org, kirill.shutemov@linux.intel.com, mike.kravetz@oracle.com, hillf.zj@alibaba-inc.com, steve.capper@arm.com, David Woods huge_pte_offset() does not correctly handle poisoned or migration page table entries. It returns NULL instead of the offset when it encounters a swap entry. This leads to errors such as [ 344.165544] mm/pgtable-generic.c:33: bad pmd 000000083af00074. in the kernel log when unmapping memory on process exit. huge_pte_offset() is now provided with the size of the hugepage being accessed. Use the size to find the correct page table entry to return. Signed-off-by: Punit Agrawal Cc: David Woods --- arch/arm64/mm/hugetlbpage.c | 30 +++++++++++++++--------------- 1 file changed, 15 insertions(+), 15 deletions(-) diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c index 1bc08ae49e6a..009648c4500f 100644 --- a/arch/arm64/mm/hugetlbpage.c +++ b/arch/arm64/mm/hugetlbpage.c @@ -194,36 +194,36 @@ pte_t *huge_pte_offset(struct mm_struct *mm, { pgd_t *pgd; pud_t *pud; - pmd_t *pmd = NULL; - pte_t *pte = NULL; + pmd_t *pmd; + pte_t *pte; pgd = pgd_offset(mm, 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)) + if (pud_none(*pud) && sz != PUD_SIZE) return NULL; - - if (pud_huge(*pud)) + else if (!pud_table(*pud)) return (pte_t *)pud; + + if (sz == CONT_PMD_SIZE) + addr &= CONT_PMD_MASK; + pmd = pmd_offset(pud, addr); - if (!pmd_present(*pmd)) + if (pmd_none(*pmd) && + !(sz == PMD_SIZE || sz == CONT_PMD_SIZE)) return NULL; - - if (pte_cont(pmd_pte(*pmd))) { - pmd = pmd_offset( - pud, (addr & CONT_PMD_MASK)); - return (pte_t *)pmd; - } - if (pmd_huge(*pmd)) + else if (!pmd_table(*pmd)) return (pte_t *)pmd; - pte = pte_offset_kernel(pmd, addr); - if (pte_present(*pte) && pte_cont(*pte)) { + + if (sz == CONT_PTE_SIZE) { pte = pte_offset_kernel( pmd, (addr & CONT_PTE_MASK)); return pte; } + return NULL; } -- 2.11.0 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org