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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AB12DC433F5 for ; Wed, 20 Apr 2022 08:14:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1376647AbiDTIRP (ORCPT ); Wed, 20 Apr 2022 04:17:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39282 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237048AbiDTIRO (ORCPT ); Wed, 20 Apr 2022 04:17:14 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F2D6DBE11; Wed, 20 Apr 2022 01:14:28 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id AD4FFB81CB4; Wed, 20 Apr 2022 08:14:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5A5B5C385A0; Wed, 20 Apr 2022 08:14:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1650442466; bh=DdB1mfY5Ea20uycDKzNuW459EQcrcZcDvQu0mVyMUCo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Ck0c0kXSpMbO/ByX93iALQ+0fpXnZ+NstX2447Jr9rmvm+DEe0eHVXozU/H/FA9pg SdQ1bzgpcDSjscOT7W0wPdNcLluL4y/PqoyIoOaL/wvmba78XDgkl1+3KMJDFJGT5C mh+qEuP7/VFrdZQTpVI0zGUMzXn6AJCmRvLvCUyARw2q8boQIkgAnZIiZDOHd+HBLM oLRhKzoyWLvXe0sZPLP0Ehv1q83q+3d1Ja2fMaLWUwrn7T/fXWfCg/y+pvgIOnMrYo OR7p74j7uiG4k+OTYUtKG4uGdTEqjX2AYfjF6ARwxBFKqFFJ6ED+WxU1qE4zg3CVnW FPGxBF31tGugw== Date: Wed, 20 Apr 2022 10:14:21 +0200 From: Christian Brauner To: syzbot , hdanton@sina.com Cc: fweisbec@gmail.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, mingo@kernel.org, syzkaller-bugs@googlegroups.com, tglx@linutronix.de, viro@zeniv.linux.org.uk Subject: Re: [syzbot] INFO: rcu detected stall in sys_setxattr (2) Message-ID: <20220420081421.r6skygdq23hesl26@wittgenstein> References: <0000000000007cc21d05dd0432b8@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <0000000000007cc21d05dd0432b8@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 19, 2022 at 09:16:20AM -0700, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: b2d229d4ddb1 Linux 5.18-rc3 > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=144417ccf00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=6cb89c879305f336 > dashboard link: https://syzkaller.appspot.com/bug?extid=10a16d1c43580983f6a2 > compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=104a88e8f00000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=132a840cf00000 > > The issue was bisected to: > > commit e257039f0fc7da36ac3a522ef9a5cb4ae7852e67 > Author: Al Viro > Date: Tue Mar 1 04:04:20 2022 +0000 > > mount_setattr(): clean the control flow and calling conventions > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=16b313c0f00000 > final oops: https://syzkaller.appspot.com/x/report.txt?x=15b313c0f00000 > console output: https://syzkaller.appspot.com/x/log.txt?x=11b313c0f00000 > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+10a16d1c43580983f6a2@syzkaller.appspotmail.com > Fixes: e257039f0fc7 ("mount_setattr(): clean the control flow and calling conventions") This suspiciously looks like in the case of failing to make a single read-write mount read-only we don't unset MNT_WRITE_HOLD in the new error path that Al added. Just saw that Hilf was testing a patch to this effect as well so putting him on this thread. Hilf, are you working on a fix for this I can pick up from you later or should I come up with a patch? Christian