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=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 97EBFC07E9B for ; Mon, 19 Jul 2021 12:18:29 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C563C6112D for ; Mon, 19 Jul 2021 12:18:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C563C6112D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 695E18D00F5; Mon, 19 Jul 2021 08:18:29 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 66D218D00EC; Mon, 19 Jul 2021 08:18:29 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 536058D00F5; Mon, 19 Jul 2021 08:18:29 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0170.hostedemail.com [216.40.44.170]) by kanga.kvack.org (Postfix) with ESMTP id 2A9678D00EC for ; Mon, 19 Jul 2021 08:18:29 -0400 (EDT) Received: from smtpin26.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id AB79F18020015 for ; Mon, 19 Jul 2021 12:18:27 +0000 (UTC) X-FDA: 78379240254.26.9AEE261 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf14.hostedemail.com (Postfix) with ESMTP id 0C350600198F for ; Mon, 19 Jul 2021 12:18:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Transfer-Encoding: Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description; bh=yk584Xxi5JgreijLkhmyuMqT8hsuugiWPk0sXg85DPc=; b=fVTrgIpdtJ9zMf/WiHGbzqdL/0 Bjbdh5PCrSP+9Y/SwPO+aV6jq6I2rweBoW3mrLFiQkQbMYbB5LlKjJvQFox9RXXs/ASPDJF8D8XGI q9ORMHpta7I5TqdS0YjnA/F315lDS2K5GQsLhCdt7z7cw4H1RmOCErBJMOJzP39u7jFb2pCA4iog9 UnhCPPKrehawCcmlnWv0NNLbIzv+f+/VdNYuKudkRQNgR282rAGFASZv2/XpnxAITFhG5bbJAL1ST Tv37ctw54UCI5ghCgR3to1iNYoKo8z2Cfe3nRZSCnJF2z1nI3/bjRzlAAAM4OQsxxWNc9KvsRYNgK PoLDfmnQ==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1m5SBo-006pjW-Ob; Mon, 19 Jul 2021 12:16:14 +0000 Date: Mon, 19 Jul 2021 13:16:04 +0100 From: Matthew Wilcox To: Oleksandr Natalenko Cc: Miaohe Lin , Boqun Feng , Zhouyi Zhou , paulmck@kernel.org, linux-kernel , stable@vger.kernel.org, Chris Clayton , Chris Rankin , Josh Triplett , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Joel Fernandes , rcu , Andrew Morton , Linux-MM , "Huang, Ying" , gregkh@linuxfoundation.org Subject: Re: linux-5.13.2: warning from kernel/rcu/tree_plugin.h:359 Message-ID: References: <2145858.R0O0FObHBN@natalenko.name> <688a2cb1-5cd8-2c00-889c-4d48021371f8@huawei.com> <5812280.fcLxn8YiTP@natalenko.name> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <5812280.fcLxn8YiTP@natalenko.name> Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=fVTrgIpd; spf=none (imf14.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none X-Stat-Signature: 7awrtmqdnckk6cnpzqn58u1inhwbcchq X-Rspamd-Queue-Id: 0C350600198F X-Rspamd-Server: rspam01 X-HE-Tag: 1626697106-261751 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 Mon, Jul 19, 2021 at 02:12:15PM +0200, 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 Li= n 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. > > >>>=20 > > >>> Oh, so this is a backport problem. 2799e77529c2 was backported w= ithout > > >>> its prerequisite 63d8620ecf93. Greg, probably best to just drop > > >>=20 > > >> Yes, they're posted as a patch set: > > >>=20 > > >> https://lkml.kernel.org/r/20210426123316.806267-1-linmiaohe@huawei= .com > > >>=20 > > >>> 2799e77529c2 from all stable trees; the race described is not ver= y > > >>> important (swapoff vs reading a page back from that swap device). > > >>> . > > >>=20 > > >> The swapoff races with reading a page back from that swap device s= hould > > >> be > > >> really uncommon as most users only do swapoff when the system is g= oing to > > >> shutdown. > > >>=20 > > >> Sorry for the trouble! > > >=20 > > > 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= locked > > > z3fold page > > > ccb7848e2344 mm/z3fold: fix potential memory leak in z3fold_destroy= _pool() > > > 9f7229c901c1 mm/huge_memory.c: don't discard hugepage if other proc= esses > > > are mapping it > > > f13259175e4f mm/huge_memory.c: add missing read-only THP checking i= n > > > transparent_hugepage_enabled() > > > afafd371e7de mm/huge_memory.c: remove dedicated macro > > > HPAGE_CACHE_INDEX_MASK a533a21b692f mm/shmem: fix shmem_swapin() ra= ce > > > with swapoff > > > c3b39134bbd0 swap: fix do_swap_page() race with swapoff > > >=20 > > > Do you suggest reverting "mm/shmem: fix shmem_swapin() race with sw= apoff" > > > as well? > >=20 > > This patch also rely on its prerequisite 63d8620ecf93. I think we sho= uld > > either revert any commit in this series or just backport the entire s= eries. >=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? Because none of these patches should have been backported in the first place. It's just not worth the destabilisation.