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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 173B9C282DC for ; Fri, 1 Feb 2019 14:28:06 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A77B6218AC for ; Fri, 1 Feb 2019 14:28:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A77B6218AC Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id E0F0E8E0002; Fri, 1 Feb 2019 09:28:04 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id DBFEE8E0001; Fri, 1 Feb 2019 09:28:04 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C87DA8E0002; Fri, 1 Feb 2019 09:28:04 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from mail-qt1-f200.google.com (mail-qt1-f200.google.com [209.85.160.200]) by kanga.kvack.org (Postfix) with ESMTP id 9B94C8E0001 for ; Fri, 1 Feb 2019 09:28:04 -0500 (EST) Received: by mail-qt1-f200.google.com with SMTP id 42so7997338qtr.7 for ; Fri, 01 Feb 2019 06:28:04 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-original-authentication-results:x-gm-message-state:subject:to:cc :references:from:openpgp:autocrypt:organization:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=7Nt1E7CNW+Jp3l4ItHB2lwY/ss8CDbizwT0xLCBIusg=; b=me0EPfJiEniqOB6dgqvdiuuR81LCMcizodl+qI9WmdFs2NGYBBmznjNS8ucFfbjojY df9uyHBrgb5iOOj/hV0RdB1+3R5fS+8byz/WEr2WdXPSNjOE9Wif3r3/UxncqVasSblx Q2I4HVVd3hIrWM/iLAba9T4UjgY54+fZb8Fq6iNiS6p/hkyMvQdVO3B6D+0MMt+GlZbD ZIIlP8MI+bmVX0X4j2U9XFqc24ZdxI6NOazya5XC3pbz3tatZy6R+67Rp7usstUhmd/m 5Ft24jkrV1GG9W8tZ4q4ArDFNzgs/e9J6XLPMLr2l4LnShhpOqsbi9Mwd9XagXtBNlMj ccrg== X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of david@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com X-Gm-Message-State: AJcUukerhrIhX+VZKrgQ8VXiA9z0npg6UpuRRIJnuRAsLpE6G89kAdJV Xj1KwodFUnlpnBapmcggxFGx27fkrPr6mSAG+vHB3zzYxv4fGU4qSwao0waIfPco4T8366BxRIR eB0cqoXKsbn3x08Cr4vD+KIRXs5V2Vce0V7RBt5hySJMs8d72ZH3a5UQe+47O5gKP3w== X-Received: by 2002:ac8:2a81:: with SMTP id b1mr39261258qta.110.1549031284275; Fri, 01 Feb 2019 06:28:04 -0800 (PST) X-Google-Smtp-Source: ALg8bN5gNU3bSp36x/zN+Y2PvJtSnLln4NzoBgX37q2xDgK9F5Z4vBgMShe4ybRztVv3kVUttJd3 X-Received: by 2002:ac8:2a81:: with SMTP id b1mr39261226qta.110.1549031283714; Fri, 01 Feb 2019 06:28:03 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1549031283; cv=none; d=google.com; s=arc-20160816; b=c7TzWbukty688wN0sRmoITJqyCiWdbtYxqEClbLnI3UPOpzU8I5cTIudva3+MGQrl8 EXwSIV4CGA2dN5WfTmcuMS3pXGTQ2yCW7/hpWre9CCsq5BXMYIcOfa6+RG18gr8jAkxj m0j5qujsJf5kWOq3XoOIcoNEz75nk99U/9x7Xtppn+0X9krKByoymbBESckORNyukwQi B2xuFVthrHTkH/Wsp7xGZwbBdGs2/mChpk+FXiWL6C0ULjRWrcg5wWtiSdtGkkDBn8al Jf1qiNIJ7yukpzYPAsNGiALHWwNWx4KqWam9Hs724uCTPTY6JqI2rsttV/7Qax7IgWGm xM3g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-transfer-encoding:content-language:in-reply-to:mime-version :user-agent:date:message-id:organization:autocrypt:openpgp:from :references:cc:to:subject; bh=7Nt1E7CNW+Jp3l4ItHB2lwY/ss8CDbizwT0xLCBIusg=; b=v2MfnL5GWQPI3SVtivio3nOigw14GsXG3Vo9LMH3czeHf1wHPfL/eT+ppBLDIRjQ9D QsLCgTCDOdSovtRmftrtEXURkblBWfFrMMVDjLN80b4TkwQwc9eUoMIvL1Kebv3wqXa1 qPfOB/fCtz7cU18850O6L9zz/3jPS+EjGGcpGzE3uRR3RKeX52TMEjkmWGu9CLsBA+FO LnQjynFvYP4ydXBZzSR0zF/CNfIf0LD64ZmlYJON9jx5BWiKba9upZ8QJP3dDp4857lo 8K5aRQvsij/tnZnCs4HjfKt7sxxMi9Neu7xHHNq8Mjei6BCisMur9wZtW0CQMFmzDCuw lU7w== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of david@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id a76si120686qkg.65.2019.02.01.06.28.03 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 01 Feb 2019 06:28:03 -0800 (PST) Received-SPF: pass (google.com: domain of david@redhat.com designates 209.132.183.28 as permitted sender) client-ip=209.132.183.28; Authentication-Results: mx.google.com; spf=pass (google.com: domain of david@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 5FC427AE9A; Fri, 1 Feb 2019 14:28:02 +0000 (UTC) Received: from [10.36.118.43] (unknown [10.36.118.43]) by smtp.corp.redhat.com (Postfix) with ESMTP id CC2D7101963F; Fri, 1 Feb 2019 14:27:56 +0000 (UTC) Subject: Re: [PATCH v2 for-4.4-stable] mm: migrate: don't rely on __PageMovable() of newpage after unlocking it To: linux-mm@kvack.org Cc: 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> 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: <59672e74-37f7-ea45-19b0-4de2fee7c58d@redhat.com> Date: Fri, 1 Feb 2019 15:27:55 +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: <20190201134347.11166-1-david@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Fri, 01 Feb 2019 14:28:02 +0000 (UTC) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 01.02.19 14:43, 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(-) > > diff --git a/mm/migrate.c b/mm/migrate.c > index afedcfab60e2..3304c98f9a78 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -936,6 +936,7 @@ static ICE_noinline int unmap_and_move(new_page_t get_new_page, > int rc = MIGRATEPAGE_SUCCESS; > int *result = NULL; > struct page *newpage; > + bool is_lru = !isolated_balloon_page(page); > > newpage = get_new_page(page, private, &result); > if (!newpage) > @@ -984,10 +985,14 @@ out: > * If migration was not successful and there's a freeing callback, use > * it. Otherwise, putback_lru_page() will drop the reference grabbed > * during isolation. > + * > + * Use the old state of the isolated source page to determine if we > + * migrated a LRU page. newpage was already unlocked and possibly > + * modified by its owner - don't rely on the page state. > */ > if (put_new_page) > put_new_page(newpage, private); > - else if (unlikely(__is_movable_balloon_page(newpage))) { And to be save, we should turn this into else if (rc == MIGRATEPAGE_SUCCESS && unlikely(!is_lru)) { But will resend this either way as already mentioned to Greg. > + else if (unlikely(!is_lru)) { > /* drop our reference, page already in the balloon */ > put_page(newpage); > } else > -- Thanks, David / dhildenb