From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8B9C7C433E3 for ; Wed, 19 Aug 2020 12:24:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6CC482075E for ; Wed, 19 Aug 2020 12:24:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597839881; bh=OVqTR+AcUCEa2DWAXeLoffzwM4Cfk47ApB6fppf3WRE=; h=Subject:To:Cc:From:Date:List-ID:From; b=UYlyb2yIoHeOwBnHFHnx88I/XleWxIooGTRFhYZhtxdF5qJmQINH1mf/ppHltjOyQ Al735Xd1v5y8f6cKuNRWTDpYbnNx+0wtUN8Gu8phEoEyfzVHKFOvGI3CZ32yTzlASX 7unnZWKvjrZftLFA8BggF5ByFvHcZjX384LjilwE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727018AbgHSMYl (ORCPT ); Wed, 19 Aug 2020 08:24:41 -0400 Received: from wforward3-smtp.messagingengine.com ([64.147.123.22]:60339 "EHLO wforward3-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726710AbgHSMYk (ORCPT ); Wed, 19 Aug 2020 08:24:40 -0400 Received: from compute1.internal (compute1.nyi.internal [10.202.2.41]) by mailforward.west.internal (Postfix) with ESMTP id 39603AEF; Wed, 19 Aug 2020 08:24:39 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute1.internal (MEProxy); Wed, 19 Aug 2020 08:24:39 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:content-type :date:from:message-id:mime-version:subject:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm3; bh=210I26 yP6HBthMZVk5uRQOrkNBT7OmQtHRxlzzsvLvQ=; b=kU07qzwMUo3Kqap1Yc+p1m O31eS0Yk5LmtqbcOOOWkOYkBnrUw8p+HGnk8whRKjnTGyIBUlidPt4RBcW5VUtus 0xRCqrXi2EDgJeU1kZR0oo4L6WV2Ha0qS4G2qFD9xvkMdM/rS/f8hwNnQ2wsbI8z kcNp7XYq8gLiSY7klzPrDME2slYohIIGRJXXz88NToB2XM8p4lZzr4el9kn7ZJzZ agwC82je+VPXgS1b9Hx67vXAGvGso56XLHHbFXbtAFP3Ure4ELBKh+LcOAVhMqDL bcip78msHQZuCFj5I0h4MFCQBhgR1L8AMw3ILNo4+kq5B4dejqIR+Annb4xht53g == X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeduiedruddtkedgfeeiucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucenucfjughrpefuvffhfffkgggtgfesthekredttd dtlfenucfhrhhomhepoehgrhgvghhkhheslhhinhhugihfohhunhgurghtihhonhdrohhr gheqnecuggftrfgrthhtvghrnhepleelledvgeefleeltdetgedugeffgffhudffudduke egfeelgeeigeekjefhleevnecuffhomhgrihhnpehkvghrnhgvlhdrohhrghenucfkphep keefrdekiedrkeelrddutdejnecuvehluhhsthgvrhfuihiivgepheenucfrrghrrghmpe hmrghilhhfrhhomhepghhrvghgsehkrhhorghhrdgtohhm X-ME-Proxy: Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) by mail.messagingengine.com (Postfix) with ESMTPA id 6284E328005A; Wed, 19 Aug 2020 08:24:38 -0400 (EDT) Subject: FAILED: patch "[PATCH] khugepaged: khugepaged_test_exit() check mmget_still_valid()" failed to apply to 4.9-stable tree To: hughd@google.com, aarcange@redhat.com, akpm@linux-foundation.org, kirill.shutemov@linux.intel.com, mike.kravetz@oracle.com, songliubraving@fb.com, stable@vger.kernel.org, torvalds@linux-foundation.org Cc: From: Date: Wed, 19 Aug 2020 14:25:00 +0200 Message-ID: <1597839900107241@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From bbe98f9cadff58cdd6a4acaeba0efa8565dabe65 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Thu, 6 Aug 2020 23:26:25 -0700 Subject: [PATCH] khugepaged: khugepaged_test_exit() check mmget_still_valid() Move collapse_huge_page()'s mmget_still_valid() check into khugepaged_test_exit() itself. collapse_huge_page() is used for anon THP only, and earned its mmget_still_valid() check because it inserts a huge pmd entry in place of the page table's pmd entry; whereas collapse_file()'s retract_page_tables() or collapse_pte_mapped_thp() merely clears the page table's pmd entry. But core dumping without mmap lock must have been as open to mistaking a racily cleared pmd entry for a page table at physical page 0, as exit_mmap() was. And we certainly have no interest in mapping as a THP once dumping core. Fixes: 59ea6d06cfa9 ("coredump: fix race condition between collapse_huge_page() and core dumping") Signed-off-by: Hugh Dickins Signed-off-by: Andrew Morton Cc: Andrea Arcangeli Cc: Song Liu Cc: Mike Kravetz Cc: Kirill A. Shutemov Cc: [4.8+] Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008021217020.27773@eggly.anvils Signed-off-by: Linus Torvalds diff --git a/mm/khugepaged.c b/mm/khugepaged.c index ac04b332a373..b52bd46ad146 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -431,7 +431,7 @@ static void insert_to_mm_slots_hash(struct mm_struct *mm, static inline int khugepaged_test_exit(struct mm_struct *mm) { - return atomic_read(&mm->mm_users) == 0; + return atomic_read(&mm->mm_users) == 0 || !mmget_still_valid(mm); } static bool hugepage_vma_check(struct vm_area_struct *vma, @@ -1100,9 +1100,6 @@ static void collapse_huge_page(struct mm_struct *mm, * handled by the anon_vma lock + PG_lock. */ mmap_write_lock(mm); - result = SCAN_ANY_PROCESS; - if (!mmget_still_valid(mm)) - goto out; result = hugepage_vma_revalidate(mm, address, &vma); if (result) goto out;