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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 9FA35C282DB for ; Fri, 1 Feb 2019 14:18:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6ED32218AC for ; Fri, 1 Feb 2019 14:18:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730041AbfBAOSP (ORCPT ); Fri, 1 Feb 2019 09:18:15 -0500 Received: from mx1.redhat.com ([209.132.183.28]:58566 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726330AbfBAOSP (ORCPT ); Fri, 1 Feb 2019 09:18:15 -0500 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 61FBA81DE9; Fri, 1 Feb 2019 14:18:14 +0000 (UTC) Received: from [10.36.118.43] (unknown [10.36.118.43]) by smtp.corp.redhat.com (Postfix) with ESMTP id 32038381B6; Fri, 1 Feb 2019 14:18:07 +0000 (UTC) Subject: Re: [PATCH v2 for-4.4-stable] mm: migrate: don't rely on __PageMovable() of newpage after unlocking it To: Greg KH Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , Mel Gorman , "Kirill A. Shutemov" , Michal Hocko , Naoya Horiguchi , Jan Kara , Andrea Arcangeli , Dominik Brodowski , Matthew Wilcox , Vratislav Bendel , Rafael Aquini , Konstantin Khlebnikov , Minchan Kim , Sasha Levin , stable@vger.kernel.org References: <20190131020448.072FE218AF@mail.kernel.org> <20190201134347.11166-1-david@redhat.com> <20190201140918.GB20335@kroah.com> From: David Hildenbrand Openpgp: preference=signencrypt Autocrypt: addr=david@redhat.com; prefer-encrypt=mutual; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwX4EEwECACgFAljj9eoCGwMFCQlmAYAGCwkI BwMCBhUIAgkKCwQWAgMBAh4BAheAAAoJEE3eEPcA/4Na5IIP/3T/FIQMxIfNzZshIq687qgG 8UbspuE/YSUDdv7r5szYTK6KPTlqN8NAcSfheywbuYD9A4ZeSBWD3/NAVUdrCaRP2IvFyELj xoMvfJccbq45BxzgEspg/bVahNbyuBpLBVjVWwRtFCUEXkyazksSv8pdTMAs9IucChvFmmq3 jJ2vlaz9lYt/lxN246fIVceckPMiUveimngvXZw21VOAhfQ+/sofXF8JCFv2mFcBDoa7eYob s0FLpmqFaeNRHAlzMWgSsP80qx5nWWEvRLdKWi533N2vC/EyunN3HcBwVrXH4hxRBMco3jvM m8VKLKao9wKj82qSivUnkPIwsAGNPdFoPbgghCQiBjBe6A75Z2xHFrzo7t1jg7nQfIyNC7ez MZBJ59sqA9EDMEJPlLNIeJmqslXPjmMFnE7Mby/+335WJYDulsRybN+W5rLT5aMvhC6x6POK z55fMNKrMASCzBJum2Fwjf/VnuGRYkhKCqqZ8gJ3OvmR50tInDV2jZ1DQgc3i550T5JDpToh dPBxZocIhzg+MBSRDXcJmHOx/7nQm3iQ6iLuwmXsRC6f5FbFefk9EjuTKcLMvBsEx+2DEx0E UnmJ4hVg7u1PQ+2Oy+Lh/opK/BDiqlQ8Pz2jiXv5xkECvr/3Sv59hlOCZMOaiLTTjtOIU7Tq 7ut6OL64oAq+zsFNBFXLn5EBEADn1959INH2cwYJv0tsxf5MUCghCj/CA/lc/LMthqQ773ga uB9mN+F1rE9cyyXb6jyOGn+GUjMbnq1o121Vm0+neKHUCBtHyseBfDXHA6m4B3mUTWo13nid 0e4AM71r0DS8+KYh6zvweLX/LL5kQS9GQeT+QNroXcC1NzWbitts6TZ+IrPOwT1hfB4WNC+X 2n4AzDqp3+ILiVST2DT4VBc11Gz6jijpC/KI5Al8ZDhRwG47LUiuQmt3yqrmN63V9wzaPhC+ xbwIsNZlLUvuRnmBPkTJwwrFRZvwu5GPHNndBjVpAfaSTOfppyKBTccu2AXJXWAE1Xjh6GOC 8mlFjZwLxWFqdPHR1n2aPVgoiTLk34LR/bXO+e0GpzFXT7enwyvFFFyAS0Nk1q/7EChPcbRb hJqEBpRNZemxmg55zC3GLvgLKd5A09MOM2BrMea+l0FUR+PuTenh2YmnmLRTro6eZ/qYwWkC u8FFIw4pT0OUDMyLgi+GI1aMpVogTZJ70FgV0pUAlpmrzk/bLbRkF3TwgucpyPtcpmQtTkWS gDS50QG9DR/1As3LLLcNkwJBZzBG6PWbvcOyrwMQUF1nl4SSPV0LLH63+BrrHasfJzxKXzqg rW28CTAE2x8qi7e/6M/+XXhrsMYG+uaViM7n2je3qKe7ofum3s4vq7oFCPsOgwARAQABwsFl BBgBAgAPBQJVy5+RAhsMBQkJZgGAAAoJEE3eEPcA/4NagOsP/jPoIBb/iXVbM+fmSHOjEshl KMwEl/m5iLj3iHnHPVLBUWrXPdS7iQijJA/VLxjnFknhaS60hkUNWexDMxVVP/6lbOrs4bDZ NEWDMktAeqJaFtxackPszlcpRVkAs6Msn9tu8hlvB517pyUgvuD7ZS9gGOMmYwFQDyytpepo YApVV00P0u3AaE0Cj/o71STqGJKZxcVhPaZ+LR+UCBZOyKfEyq+ZN311VpOJZ1IvTExf+S/5 lqnciDtbO3I4Wq0ArLX1gs1q1XlXLaVaA3yVqeC8E7kOchDNinD3hJS4OX0e1gdsx/e6COvy qNg5aL5n0Kl4fcVqM0LdIhsubVs4eiNCa5XMSYpXmVi3HAuFyg9dN+x8thSwI836FoMASwOl C7tHsTjnSGufB+D7F7ZBT61BffNBBIm1KdMxcxqLUVXpBQHHlGkbwI+3Ye+nE6HmZH7IwLwV W+Ajl7oYF+jeKaH4DZFtgLYGLtZ1LDwKPjX7VAsa4Yx7S5+EBAaZGxK510MjIx6SGrZWBrrV TEvdV00F2MnQoeXKzD7O4WFbL55hhyGgfWTHwZ457iN9SgYi1JLPqWkZB0JRXIEtjd4JEQcx +8Umfre0Xt4713VxMygW0PnQt5aSQdMD58jHFxTk092mU+yIHj5LeYgvwSgZN4airXk5yRXl SE+xAvmumFBY Organization: Red Hat GmbH Message-ID: <518dd92f-f017-707a-ea36-bcb97e67168e@redhat.com> Date: Fri, 1 Feb 2019 15:18:06 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.1 MIME-Version: 1.0 In-Reply-To: <20190201140918.GB20335@kroah.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Fri, 01 Feb 2019 14:18:14 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01.02.19 15:09, Greg KH wrote: > On Fri, Feb 01, 2019 at 02:43:47PM +0100, David Hildenbrand wrote: >> This is the backport for 4.4-stable. >> >> We had a race in the old balloon compaction code before commit b1123ea6d3b3 >> ("mm: balloon: use general non-lru movable page feature") refactored it >> that became visible after backporting commit 195a8c43e93d >> ("virtio-balloon: deflate via a page list") without the refactoring. >> >> The bug existed from commit d6d86c0a7f8d ("mm/balloon_compaction: redesign >> ballooned pages management") till commit b1123ea6d3b3 ("mm: balloon: use >> general non-lru movable page feature"). commit d6d86c0a7f8d >> ("mm/balloon_compaction: redesign ballooned pages management") was >> backported to 3.12, so the broken kernels are stable kernels [3.12 - 4.7]. >> >> There was a subtle race between dropping the page lock of the newpage >> in __unmap_and_move() and checking for >> __is_movable_balloon_page(newpage). >> >> Just after dropping this page lock, virtio-balloon could go ahead and >> deflate the newpage, effectively dequeueing it and clearing PageBalloon, >> in turn making __is_movable_balloon_page(newpage) fail. >> >> This resulted in dropping the reference of the newpage via >> putback_lru_page(newpage) instead of put_page(newpage), leading to >> page->lru getting modified and a !LRU page ending up in the LRU lists. >> With commit 195a8c43e93d ("virtio-balloon: deflate via a page list") >> backported, one would suddenly get corrupted lists in >> release_pages_balloon(): >> - WARNING: CPU: 13 PID: 6586 at lib/list_debug.c:59 __list_del_entry+0xa1/0xd0 >> - list_del corruption. prev->next should be ffffe253961090a0, but was dead000000000100 >> >> Nowadays this race is no longer possible, but it is hidden behind very >> ugly handling of __ClearPageMovable() and __PageMovable(). >> >> __ClearPageMovable() will not make __PageMovable() fail, only >> PageMovable(). So the new check (__PageMovable(newpage)) will still hold >> even after newpage was dequeued by virtio-balloon. >> >> If anybody would ever change that special handling, the BUG would be >> introduced again. So instead, make it explicit and use the information >> of the original isolated page before migration. >> >> This patch can be backported fairly easy to stable kernels (in contrast >> to the refactoring). >> >> Cc: Andrew Morton >> Cc: Mel Gorman >> Cc: "Kirill A. Shutemov" >> Cc: Michal Hocko >> Cc: Naoya Horiguchi >> Cc: Jan Kara >> Cc: Andrea Arcangeli >> Cc: Dominik Brodowski >> Cc: Matthew Wilcox >> Cc: Vratislav Bendel >> Cc: Rafael Aquini >> Cc: Konstantin Khlebnikov >> Cc: Minchan Kim >> Cc: Sasha Levin >> Cc: stable@vger.kernel.org # 3.12 - 4.7 >> Fixes: d6d86c0a7f8d ("mm/balloon_compaction: redesign ballooned pages management") >> Reported-by: Vratislav Bendel >> Acked-by: Michal Hocko >> Acked-by: Rafael Aquini >> Signed-off-by: David Hildenbrand >> --- >> mm/migrate.c | 7 ++++++- >> 1 file changed, 6 insertions(+), 1 deletion(-) > > What is the git commit id of this patch in Linus's tree? It's still in Andrew's tree as far as I know. I just wanted to share the backport right away (to show that it is easy :) ). Will resend it again (with proper commit idea) once upstream. > > thanks, > > greg k-h > -- Thanks, David / dhildenb