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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 2309BC07E9D for ; Mon, 19 Jul 2021 12:17:49 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D0C036115B for ; Mon, 19 Jul 2021 12:17:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D0C036115B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 5D3AF8D00F4; Mon, 19 Jul 2021 08:17:49 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 5AA7A8D00EC; Mon, 19 Jul 2021 08:17:49 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4741F8D00F4; Mon, 19 Jul 2021 08:17:49 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0050.hostedemail.com [216.40.44.50]) by kanga.kvack.org (Postfix) with ESMTP id 221968D00EC for ; Mon, 19 Jul 2021 08:17:49 -0400 (EDT) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id B7FF38249980 for ; Mon, 19 Jul 2021 12:17:47 +0000 (UTC) X-FDA: 78379238574.22.8A91A72 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by imf06.hostedemail.com (Postfix) with ESMTP id E2071801F27F for ; Mon, 19 Jul 2021 12:17:45 +0000 (UTC) Received: from dggeme703-chm.china.huawei.com (unknown [172.30.72.53]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4GT13c3yQpz7whb; Mon, 19 Jul 2021 20:14:04 +0800 (CST) Received: from [10.174.177.180] (10.174.177.180) by dggeme703-chm.china.huawei.com (10.1.199.99) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2176.2; Mon, 19 Jul 2021 20:17:41 +0800 Subject: Re: linux-5.13.2: warning from kernel/rcu/tree_plugin.h:359 To: Oleksandr Natalenko , Matthew Wilcox CC: Boqun Feng , Zhouyi Zhou , , linux-kernel , , Chris Clayton , Chris Rankin , Josh Triplett , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Joel Fernandes , rcu , Andrew Morton , Linux-MM , "Huang, Ying" , References: <2145858.R0O0FObHBN@natalenko.name> <688a2cb1-5cd8-2c00-889c-4d48021371f8@huawei.com> <5812280.fcLxn8YiTP@natalenko.name> From: Miaohe Lin Message-ID: <8c2317d0-0956-8f05-d6bf-bcd381c8fcee@huawei.com> Date: Mon, 19 Jul 2021 20:17:41 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: <5812280.fcLxn8YiTP@natalenko.name> Content-Type: text/plain; charset="utf-8" Content-Language: en-US X-Originating-IP: [10.174.177.180] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggeme703-chm.china.huawei.com (10.1.199.99) X-CFilter-Loop: Reflected X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: E2071801F27F X-Stat-Signature: yopsgaxsx54p97dip6shp9ygb59bdscd Authentication-Results: imf06.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=huawei.com; spf=pass (imf06.hostedemail.com: domain of linmiaohe@huawei.com designates 45.249.212.188 as permitted sender) smtp.mailfrom=linmiaohe@huawei.com X-HE-Tag: 1626697065-526204 Content-Transfer-Encoding: quoted-printable 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 2021/7/19 20:12, Oleksandr Natalenko wrote: > On pond=C4=9Bl=C3=AD 19. =C4=8Dervence 2021 14:08:37 CEST Miaohe Lin wr= ote: >> On 2021/7/19 19:59, Oleksandr Natalenko wrote: >>> On pond=C4=9Bl=C3=AD 19. =C4=8Dervence 2021 13:50:07 CEST Miaohe Lin = wrote: >>>> On 2021/7/19 19:22, Matthew Wilcox wrote: >>>>> On Mon, Jul 19, 2021 at 07:12:58PM +0800, Miaohe Lin wrote: >>>>>> When in the commit 2799e77529c2a, we're using the percpu_ref to >>>>>> serialize >>>>>> against concurrent swapoff, i.e. there's percpu_ref inside >>>>>> get_swap_device() instead of rcu_read_lock(). Please see commit >>>>>> 63d8620ecf93 ("mm/swapfile: use percpu_ref to serialize against >>>>>> concurrent swapoff") for detail. >>>>> >>>>> Oh, so this is a backport problem. 2799e77529c2 was backported wit= hout >>>>> its prerequisite 63d8620ecf93. Greg, probably best to just drop >>>> >>>> Yes, they're posted as a patch set: >>>> >>>> https://lkml.kernel.org/r/20210426123316.806267-1-linmiaohe@huawei.c= om >>>> >>>>> 2799e77529c2 from all stable trees; the race described is not very >>>>> important (swapoff vs reading a page back from that swap device). >>>>> . >>>> >>>> The swapoff races with reading a page back from that swap device sho= uld >>>> be >>>> really uncommon as most users only do swapoff when the system is goi= ng to >>>> shutdown. >>>> >>>> Sorry for the trouble! >>> >>> git log --oneline v5.13..v5.13.3 --author=3D"Miaohe Lin" >>> 11ebc09e50dc mm/zswap.c: fix two bugs in zswap_writeback_entry() >>> 95d192da198d mm/z3fold: use release_z3fold_page_locked() to release l= ocked >>> z3fold page >>> ccb7848e2344 mm/z3fold: fix potential memory leak in z3fold_destroy_p= ool() >>> 9f7229c901c1 mm/huge_memory.c: don't discard hugepage if other proces= ses >>> are mapping it >>> f13259175e4f mm/huge_memory.c: add missing read-only THP checking in >>> transparent_hugepage_enabled() >>> afafd371e7de mm/huge_memory.c: remove dedicated macro >>> HPAGE_CACHE_INDEX_MASK a533a21b692f mm/shmem: fix shmem_swapin() race >>> with swapoff >>> c3b39134bbd0 swap: fix do_swap_page() race with swapoff >>> >>> Do you suggest reverting "mm/shmem: fix shmem_swapin() race with swap= off" >>> as well? >> >> This patch also rely on its prerequisite 63d8620ecf93. I think we shou= ld >> either revert any commit in this series or just backport the entire se= ries. >=20 > Then why not just pick up 2 more patches instead of dropping 2 patches.= Greg,=20 > could you please make sure the whole series from [1] gets pulled? >=20 > Thanks. >=20 > [1] https://lkml.kernel.org/r/20210426123316.806267-1-linmiaohe@huawei.= com >=20 I browsed the previous backport notifying email and found that these two = patches are also backported into 5.10 and 5.12. So we might also need to make sure the who= le series from [1] gets pulled in 5.10 and 5.12. Thanks.