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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 0A2F1C63798 for ; Thu, 22 Jul 2021 12:36:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E5EE56109D for ; Thu, 22 Jul 2021 12:36:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231868AbhGVL4J (ORCPT ); Thu, 22 Jul 2021 07:56:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47922 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231738AbhGVL4I (ORCPT ); Thu, 22 Jul 2021 07:56:08 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 68505C061575; Thu, 22 Jul 2021 05:36:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=NG4N/2H3vvAjRHdDWUczi40Y7/Fx7mV5GVuGOtkatQQ=; b=R0sVlJzxfmtaJ6WvW3j1P24Mck t79mECEBGb+nkFlOvxz64p03TMuphOOxmn0+I8v1F1lRm+D/cvj3h/TA3u6WQWtpycj+xWBmNl9nf s/ENwBtucNIFCdCkD2oLdVmzoypMgwjaur21zn9S/SI92T1qohIzy4OGR5WamZAF6p0SJAD3loC2N 99fCSQrJSH9Z8qV5tGB8/5FMZVFCVDRPmHwX1qge2T6Wv4i6xUoorsF2F804YyXkwklybkJJitkgl NCQ6mxnpuTyUyw8tC8v/33aSpL3cX2VNztqLZNefTLOLH674JYKxAr5PoNIuoh0tn8hiohSCet+1h RrZEAfCg==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1m6Xvm-00AFjQ-FL; Thu, 22 Jul 2021 12:36:09 +0000 Date: Thu, 22 Jul 2021 13:36:02 +0100 From: Matthew Wilcox To: Zhouyi Zhou Cc: Chris Clayton , Oleksandr Natalenko , Miaohe Lin , Boqun Feng , paulmck@kernel.org, linux-kernel , stable@vger.kernel.org, Chris Rankin , Josh Triplett , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Joel Fernandes , rcu , Andrew Morton , Linux-MM , "Huang, Ying" , Greg KH Subject: Re: linux-5.13.2: warning from kernel/rcu/tree_plugin.h:359 Message-ID: References: <5812280.fcLxn8YiTP@natalenko.name> <2237123.PRLUojbHBq@natalenko.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 22, 2021 at 04:57:57PM +0800, Zhouyi Zhou wrote: > Thanks for reviewing, > > What I have deduced from the dmesg is: > In function do_swap_page, > after invoking > 3385 si = get_swap_device(entry); /* rcu_read_lock */ > and before > 3561 out: > 3562 if (si) > 3563 put_swap_device(si); > The thread got scheduled out in > 3454 locked = lock_page_or_retry(page, vma->vm_mm, vmf->flags); > > I am only familiar with Linux RCU subsystem, hope mm people can solve our > confusions. I don't understamd why you're still talking. The problem is understood. You need to revert the unnecessary backport of 2799e77529c2 and 2efa33fc7f6e