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=-10.3 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=ham 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 6F70DC4727C for ; Tue, 29 Sep 2020 14:30:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1078520739 for ; Tue, 29 Sep 2020 14:30:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730211AbgI2Oad (ORCPT ); Tue, 29 Sep 2020 10:30:33 -0400 Received: from mx2.suse.de ([195.135.220.15]:44128 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725554AbgI2Oad (ORCPT ); Tue, 29 Sep 2020 10:30:33 -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 E61E1AD0F; Tue, 29 Sep 2020 14:30:31 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id 5BF841E12E9; Tue, 29 Sep 2020 16:30:31 +0200 (CEST) Date: Tue, 29 Sep 2020 16:30:31 +0200 From: Jan Kara To: Takashi Iwai Cc: syzbot , adi@adirat.com, alsa-devel@alsa-project.org, coreteam@netfilter.org, davem@davemloft.net, jack@suse.com, kaber@trash.net, kadlec@blackhole.kfki.hu, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, netfilter-devel@vger.kernel.org, pablo@netfilter.org, perex@perex.cz, syzkaller-bugs@googlegroups.com, tiwai@suse.com Subject: Re: BUG: unable to handle kernel paging request in dqput Message-ID: <20200929143031.GP10896@quack2.suse.cz> References: <00000000000067becf05b03d8dd6@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun 27-09-20 09:07:02, Takashi Iwai wrote: > On Sat, 26 Sep 2020 22:48:15 +0200, > syzbot wrote: > > > > Hello, > > > > syzbot found the following issue on: > > > > HEAD commit: 98477740 Merge branch 'rcu/urgent' of git://git.kernel.org.. > > git tree: upstream > > console output: https://syzkaller.appspot.com/x/log.txt?x=17930875900000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=af502ec9a451c9fc > > dashboard link: https://syzkaller.appspot.com/bug?extid=f816042a7ae2225f25ba > > compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81) > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=133783ab900000 > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13bb5973900000 > > > > The issue was bisected to: > > > > commit 1d0f953086f090a022f2c0e1448300c15372db46 > > Author: Ioan-Adrian Ratiu > > Date: Wed Jan 4 22:37:46 2017 +0000 > > > > ALSA: usb-audio: Fix irq/process data synchronization > > > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=133362c3900000 > > final oops: https://syzkaller.appspot.com/x/report.txt?x=10b362c3900000 > > console output: https://syzkaller.appspot.com/x/log.txt?x=173362c3900000 > > This commit looks really irrelevant from the Oops code path. > It must be a different reason. Yeah, it seems the bisection got confused because it hit a different error during the bisection. Looking at the original oops, I think the actual reason of a crash is that quota file got corrupted in a particular way. Quota code is not very paranoid when checking on disk contents. I'll work on adding more sanity checks to quota code... Honza -- Jan Kara SUSE Labs, CR