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=-7.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_2 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 C9351C433FF for ; Wed, 7 Aug 2019 13:37:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9C27221922 for ; Wed, 7 Aug 2019 13:37:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388240AbfHGNh3 (ORCPT ); Wed, 7 Aug 2019 09:37:29 -0400 Received: from mx2.suse.de ([195.135.220.15]:42292 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2387982AbfHGNh2 (ORCPT ); Wed, 7 Aug 2019 09:37:28 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 8735DAEF3; Wed, 7 Aug 2019 13:37:27 +0000 (UTC) Message-ID: <1565185044.15973.0.camel@suse.com> Subject: Re: possible deadlock in open_rio From: Oliver Neukum To: Alan Stern , syzbot Cc: miquel@df.uba.ar, andreyknvl@google.com, syzkaller-bugs@googlegroups.com, gregkh@linuxfoundation.org, rio500-users@lists.sourceforge.net, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org Date: Wed, 07 Aug 2019 15:37:24 +0200 In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.26.6 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org Am Dienstag, den 06.08.2019, 15:13 -0400 schrieb Alan Stern: > On Thu, 1 Aug 2019, syzbot wrote: > > > Hello, > > > > syzbot found the following crash on: > > > > HEAD commit: 7f7867ff usb-fuzzer: main usb gadget fuzzer driver > > git tree: https://github.com/google/kasan.git usb-fuzzer > > console output: https://syzkaller.appspot.com/x/log.txt?x=136b6aec600000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=792eb47789f57810 > > dashboard link: https://syzkaller.appspot.com/bug?extid=7bbcbe9c9ff0cd49592a > > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > > > > Unfortunately, I don't have any reproducer for this crash yet. > > > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > > Reported-by: syzbot+7bbcbe9c9ff0cd49592a@syzkaller.appspotmail.com > > > > ====================================================== > > WARNING: possible circular locking dependency detected > > 5.3.0-rc2+ #23 Not tainted > > ------------------------------------------------------ > > Andrey: > > This should be completely reproducible, since it's a simple ABBA > locking violation. Maybe just introducing a time delay (to avoid races > and give the open() call time to run) between the gadget creation and > gadget removal would be enough to do it. Hi, technically yes. However in practical terms the straight revert I sent out yesterday should fix it. Regards Oliver