From patchwork Wed Jun 15 20:06:10 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Kirill A . Shutemov" X-Patchwork-Id: 9179407 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 81B0F604DB for ; Wed, 15 Jun 2016 20:18:28 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6F58227F07 for ; Wed, 15 Jun 2016 20:18:28 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 626D1269E2; Wed, 15 Jun 2016 20:18:28 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 192F5269E2 for ; Wed, 15 Jun 2016 20:18:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933125AbcFOURd (ORCPT ); Wed, 15 Jun 2016 16:17:33 -0400 Received: from mga02.intel.com ([134.134.136.20]:22147 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933049AbcFOUG7 (ORCPT ); Wed, 15 Jun 2016 16:06:59 -0400 Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga101.jf.intel.com with ESMTP; 15 Jun 2016 13:06:59 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.26,477,1459839600"; d="scan'208";a="828804245" Received: from black.fi.intel.com ([10.237.72.93]) by orsmga003.jf.intel.com with ESMTP; 15 Jun 2016 13:06:54 -0700 Received: by black.fi.intel.com (Postfix, from userid 1000) id CAD99603; Wed, 15 Jun 2016 23:06:48 +0300 (EEST) From: "Kirill A. Shutemov" To: Hugh Dickins , Andrea Arcangeli , Andrew Morton Cc: Dave Hansen , Vlastimil Babka , Christoph Lameter , Naoya Horiguchi , Jerome Marchand , Yang Shi , Sasha Levin , Andres Lagar-Cavilla , Ning Qu , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Ebru Akagunduz , "Kirill A. Shutemov" Subject: [PATCHv9-rebased2 05/37] khugepaged: recheck pmd after mmap_sem re-acquired Date: Wed, 15 Jun 2016 23:06:10 +0300 Message-Id: <1466021202-61880-6-git-send-email-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.8.1 In-Reply-To: <1466021202-61880-1-git-send-email-kirill.shutemov@linux.intel.com> References: <1465222029-45942-1-git-send-email-kirill.shutemov@linux.intel.com> <1466021202-61880-1-git-send-email-kirill.shutemov@linux.intel.com> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Vlastimil noted[1] that pmd can be no longer valid after we drop mmap_sem. We need recheck it once mmap_sem taken again. [1] http://lkml.kernel.org/r/12918dcd-a695-c6f4-e06f-69141c5f357f@suse.cz Signed-off-by: Kirill A. Shutemov --- mm/huge_memory.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index d7ccc8558187..0efdad975659 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2437,6 +2437,9 @@ static bool __collapse_huge_page_swapin(struct mm_struct *mm, /* vma is no longer available, don't continue to swapin */ if (hugepage_vma_revalidate(mm, address)) return false; + /* check if the pmd is still valid */ + if (mm_find_pmd(mm, address) != pmd) + return false; } if (ret & VM_FAULT_ERROR) { trace_mm_collapse_huge_page_swapin(mm, swapped_in, 0); @@ -2522,6 +2525,9 @@ static void collapse_huge_page(struct mm_struct *mm, result = hugepage_vma_revalidate(mm, address); if (result) goto out; + /* check if the pmd is still valid */ + if (mm_find_pmd(mm, address) != pmd) + goto out; anon_vma_lock_write(vma->anon_vma);