From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756347AbeDFO1M (ORCPT ); Fri, 6 Apr 2018 10:27:12 -0400 Received: from mail-it0-f41.google.com ([209.85.214.41]:54002 "EHLO mail-it0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752447AbeDFO1J (ORCPT ); Fri, 6 Apr 2018 10:27:09 -0400 X-Google-Smtp-Source: AIpwx48FIyeO9AaVf9ZU4MUe8e6QT2yLyMAYzJFdveL/wKg8M3cGgS1hkw49C2Jmkm+GJZRpDfGW6w== Subject: Re: WARNING: lock held when returning to user space! To: syzbot , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, Omar Sandoval References: <00000000000082922905692da9e1@google.com> From: Jens Axboe Message-ID: <0e998b77-14f0-aee0-8d32-bc1dd96fcc4c@kernel.dk> Date: Fri, 6 Apr 2018 08:27:06 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.0 MIME-Version: 1.0 In-Reply-To: <00000000000082922905692da9e1@google.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 4/6/18 7:02 AM, syzbot wrote: > Hello, > > syzbot hit the following crash on upstream commit > 38c23685b273cfb4ccf31a199feccce3bdcb5d83 (Fri Apr 6 04:29:35 2018 +0000) > Merge tag 'armsoc-drivers' of > git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc > syzbot dashboard link: > https://syzkaller.appspot.com/bug?extid=31e8daa8b3fc129e75f2 > > So far this crash happened 9 times on upstream. > C reproducer: https://syzkaller.appspot.com/x/repro.c?id=6407930337296384 > syzkaller reproducer: > https://syzkaller.appspot.com/x/repro.syz?id=4942413340606464 > Raw console output: > https://syzkaller.appspot.com/x/log.txt?id=4764483918495744 > Kernel config: > https://syzkaller.appspot.com/x/.config?id=-5813481738265533882 > compiler: gcc (GCC) 8.0.1 20180301 (experimental) > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+31e8daa8b3fc129e75f2@syzkaller.appspotmail.com > It will help syzbot understand when the bug is fixed. See footer for > details. > If you forward the report, please keep this part and the footer. > > > ================================================ > WARNING: lock held when returning to user space! > 4.16.0+ #3 Not tainted > ------------------------------------------------ > syzkaller433111/4462 is leaving the kernel with locks still held! > 1 lock held by syzkaller433111/4462: > #0: 0000000003a06fae (&lo->lo_ctl_mutex/1){+.+.}, at: lo_ioctl+0x8d/0x1ec0 > drivers/block/loop.c:1363 Is this a new regression? Omar did just fiddle with the locking a bit, seems suspicious. -- Jens Axboe