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=-13.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL 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 09836C433FF for ; Wed, 7 Aug 2019 13:54:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D525221E6E for ; Wed, 7 Aug 2019 13:54:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="eyUcy5z6" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387998AbfHGNyE (ORCPT ); Wed, 7 Aug 2019 09:54:04 -0400 Received: from mail-pl1-f194.google.com ([209.85.214.194]:44044 "EHLO mail-pl1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387945AbfHGNyD (ORCPT ); Wed, 7 Aug 2019 09:54:03 -0400 Received: by mail-pl1-f194.google.com with SMTP id t14so40909531plr.11 for ; Wed, 07 Aug 2019 06:54:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=RoWuMVNmRfMP6twJoSi1+gPLSwhvWNnJuHSrIbb4GeQ=; b=eyUcy5z6yfw7W/XYFZBrztR051qXApfEiFeV/KKMElwaltRh01FBH4xOMriqmhXp0S n/v5K2gv8DkzWqmgi3OPIu/uZeatsk/e4eUzGdC/tnfmx7B5olD03Ys6HOFk0rzfIFkk oA/DgVgpEyMOza2fUdSzLIot4e5OEk2/nTGtVCQ2ueoFhiMdtb2PXRsIn7WBf++sEABC Yi2PICeym++vGALaVMd2XCJIW5JRrrpqhh+wohmHf72c1gY2dgUH/Ba6AsPkvF3kqNnc T57wge3JXy4SGLqEQyZQTkK0m1+nxgiYoRdzni+bWhDOBzPPRY7SqyxSbC2ICet8Abbo 9JdQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=RoWuMVNmRfMP6twJoSi1+gPLSwhvWNnJuHSrIbb4GeQ=; b=PlcElI1S2HAnGK1tEaDIsXEnOpFV75ExgjwLtNB4ZnffSpU2nQ0EDcC/nF3LvwShsY vu7ZpMPOHQtQX/89HQHHdmjc5EPV8C0EJFdFLIydoxwaZS6qijCfMVWI3hDHwnnP4Ok2 rSHDjKE3qr6oPzvEVK+8oh9pFNeoaxeGfLwVpKypY3XuLq6wdfKA4b6e2V9cH2xarB8K KpVvq03PHgpQn3fVlGJbTHtLB326AqPRD0l713qFRmgFEHPMQGlCBC0Swue5tMmo7Cwo CMl1AkZKxd+xnPnC3YwNen/lKvjdNrYQzImxsH6R74MmpzjmUbrZXCP7/F8QIYbhljDX acRQ== X-Gm-Message-State: APjAAAXwu/yrMdL4KWc+LtYyeBGVuSqe79xtlbcDwq3KbBYyyajcix2D qj+d1RfaScIlrFDP1uqP39sJxOcn4TYEJbsvoRDdJA== X-Google-Smtp-Source: APXvYqyvTTzfZlxz9lgLLA6e7+UPFvYSd1PebuD8n5S/aCiPLUwVFCoM3CmHUJckUsWy/8R2gqFgH/Uhfolr9hDtZBQ= X-Received: by 2002:a63:c442:: with SMTP id m2mr8020736pgg.286.1565186041896; Wed, 07 Aug 2019 06:54:01 -0700 (PDT) MIME-Version: 1.0 References: <00000000000088af91058f0fe377@google.com> In-Reply-To: From: Andrey Konovalov Date: Wed, 7 Aug 2019 15:53:50 +0200 Message-ID: Subject: Re: possible deadlock in open_rio To: Alan Stern Cc: syzbot , Greg Kroah-Hartman , LKML , USB list , Cesar Miquel , rio500-users@lists.sourceforge.net, syzkaller-bugs Content-Type: text/plain; charset="UTF-8" Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Tue, Aug 6, 2019 at 9:13 PM Alan Stern wrote: > > 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. I've tried some simple approaches to reproducing this, but failed. Should this require two rio500 devices to trigger? > > Is there any way you can test this? Not yet. > > Alan Stern >