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=-10.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 0AF21C43461 for ; Tue, 15 Sep 2020 08:01:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C1D3D20715 for ; Tue, 15 Sep 2020 08:01:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726208AbgIOIBU (ORCPT ); Tue, 15 Sep 2020 04:01:20 -0400 Received: from mx2.suse.de ([195.135.220.15]:45986 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726328AbgIOH7c (ORCPT ); Tue, 15 Sep 2020 03:59:32 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 3FFFFAC7D; Tue, 15 Sep 2020 07:59:21 +0000 (UTC) Received: by ds.suse.cz (Postfix, from userid 10065) id 86CDDDA7C7; Tue, 15 Sep 2020 09:57:54 +0200 (CEST) Date: Tue, 15 Sep 2020 09:57:54 +0200 From: David Sterba To: Nikolay Borisov Cc: syzbot , clm@fb.com, dsterba@suse.com, josef@toxicpanda.com, linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk Subject: Re: INFO: task hung in vfs_setxattr (3) Message-ID: <20200915075754.GE1791@twin.jikos.cz> Reply-To: dsterba@suse.cz Mail-Followup-To: dsterba@suse.cz, Nikolay Borisov , syzbot , clm@fb.com, dsterba@suse.com, josef@toxicpanda.com, linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk References: <0000000000008a633505af53038f@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.23.1-rc1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 15, 2020 at 10:26:26AM +0300, Nikolay Borisov wrote: > > > On 15.09.20 г. 7:59 ч., syzbot wrote: > > Hello, > > > > syzbot found the following issue on: > > > > HEAD commit: 7fe10096 Merge branch 'linus' of git://git.kernel.org/pub/.. > > git tree: upstream > > console output: https://syzkaller.appspot.com/x/log.txt?x=140b0853900000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=a9075b36a6ae26c9 > > dashboard link: https://syzkaller.appspot.com/bug?extid=738cca7d7d9754493513 > > compiler: gcc (GCC) 10.1.0-syz 20200507 > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=108d45a5900000 > > > > The issue was bisected to: > > > > commit 6a3c7f5c87854e948c3c234e5f5e745c7c553722 > > Author: Nikolay Borisov > > Date: Thu May 28 08:05:13 2020 +0000 > > > > btrfs: don't balance btree inode pages from buffered write path > > > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=14884d21900000 > > final oops: https://syzkaller.appspot.com/x/report.txt?x=16884d21900000 > > console output: https://syzkaller.appspot.com/x/log.txt?x=12884d21900000 > > > Unlikely, that patch does change the performance characteristics because > now we don't balance metadata when doing buffered writes but I don't see > how it can lead to a hang. Yeah, this patch once got pointed to by syzbot bisection supposedly causing bug in a completely unrelated subsystem, but it's more likely that it's making the bisection unreliable. https://lore.kernel.org/lkml/20200811065013.GI2026@twin.jikos.cz/