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=-15.1 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_PASS,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL 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 0FD0BC43441 for ; Wed, 14 Nov 2018 18:02:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C600F22419 for ; Wed, 14 Nov 2018 18:02:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="hALzE4eW" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C600F22419 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732108AbeKOEGX (ORCPT ); Wed, 14 Nov 2018 23:06:23 -0500 Received: from mail-it1-f196.google.com ([209.85.166.196]:36232 "EHLO mail-it1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727821AbeKOEGX (ORCPT ); Wed, 14 Nov 2018 23:06:23 -0500 Received: by mail-it1-f196.google.com with SMTP id w7-v6so25260683itd.1 for ; Wed, 14 Nov 2018 10:02:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=+u9cfa/TTF/uy2o+d2SBUGl/+F7AsRzMtsTN9wc4rW0=; b=hALzE4eWK9dzsmS9Pxdaht0tHKnRuKiRI59nvdvANVeTcaB3sBX0iDrgsK9D1zv5J0 trcZOqG5sB3N41i7f+mBCOcvwJtdU9fFO73FHVewaFuLlMw/PZdJE+1DHgpqAuNhHvG+ G+kaF67JZ6K/OuoEModdU35BrClI63NXbqrENh3La9yweDEQ0LvWwCyH6tEqLVzOyg4m C5n4801az1bVUUUqS/xff33jAABRQdspxfE5PRcYwo5/uLVkaecu46g6fEXpBWH36zRC nLC/PwPnEy/SxgO9CkTymr/46nGQPxSp7y2yITDhDQc2QMGOLinb303P4Y/+9TDawnRa iWbg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=+u9cfa/TTF/uy2o+d2SBUGl/+F7AsRzMtsTN9wc4rW0=; b=Z3KTkTqGpzWe/RGneWQLmGx7GbOVCP0WcekeUkoOOc76Xu1awQSNkASxovboZyq/dQ HuSAlOGTeCcyFgoE7c98UtZnSnB1S5yZaYz0IcZtHSoHEvxtpRIWyivwpMUdmOdqeXdQ aCgPAzVNL0ElpIFquZx7nci+7ynJSoKoddCdNWLr5etyZ3rkz1WZqA0CYurwcqMJCAU7 KnQsxWiHswQPM7Wvh36t29uCcRRL9kCxvNvnM6RxYaZvIJQMlLz3FhjpoxVWMIAMnPn6 1qMBbR8F7WshBmjoiqGXI3YK3AGHDt/ft8EH6g7K9M9TUncSGW8oDDH4yOXHGYN1eMgq ktzA== X-Gm-Message-State: AA+aEWZoZM4GwkCGJaraqocQkPyfV8Cl/ErYsyn7RRyLlGQbJTKqgMUa fmjxeEgPDXZTGuVRGl1bq/t5mZDVnXoDNogVsU1syQ== X-Google-Smtp-Source: AFSGD/U8Nc+Ze3x7JaefP58K64Pdmg2+BmGDyNfnJDz9nXJeGP+WBolQtff2ldPMvw+XOWiJH+IoI2tQ6y53bQ7hWgk= X-Received: by 2002:a24:e0b:: with SMTP id 11-v6mr2519346ite.41.1542218529866; Wed, 14 Nov 2018 10:02:09 -0800 (PST) MIME-Version: 1.0 Received: by 2002:a02:7050:0:0:0:0:0 with HTTP; Wed, 14 Nov 2018 10:02:09 -0800 (PST) In-Reply-To: References: <000000000000214dc1057a74d206@google.com> From: Andrey Konovalov Date: Wed, 14 Nov 2018 19:02:09 +0100 Message-ID: Subject: Re: WARNING in usb_submit_urb (4) To: Alan Stern Cc: syzbot , Thinh.Nguyen@synopsys.com, Felipe Balbi , Greg Kroah-Hartman , LKML , USB list , Shuah Khan , syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 13, 2018 at 9:37 PM, Alan Stern wrote: > On Mon, 12 Nov 2018, syzbot wrote: > >> syzbot has found a reproducer for the following crash on: >> >> HEAD commit: e12e00e388de Merge tag 'kbuild-fixes-v4.20' of git://git.k.. >> git tree: upstream >> console output: https://syzkaller.appspot.com/x/log.txt?x=100e4ef5400000 >> kernel config: https://syzkaller.appspot.com/x/.config?x=8f215f21f041a0d7 >> dashboard link: https://syzkaller.appspot.com/bug?extid=7634edaea4d0b341c625 >> compiler: gcc (GCC) 8.0.1 20180413 (experimental) >> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11ce6fbd400000 >> >> IMPORTANT: if you fix the bug, please add the following tag to the commit: >> Reported-by: syzbot+7634edaea4d0b341c625@syzkaller.appspotmail.com > > I tried reproducing this bug on my own system, following the > instructions at > > https://github.com/google/syzkaller/blob/master/docs/executing_syzkaller_programs.md > > The reproducer failed to run properly. It produced the following > output: > > > $ ./syz-execprog -cover=0 -threaded=1 -repeat=1 -procs=4 /tmp/repro.syz > 2018/11/13 15:29:32 parsed 1 programs > 2018/11/13 15:29:32 executed programs: 0 > 2018/11/13 15:29:32 result: failed=false hanged=false err=executor 3: failed: tun: ioctl(TUNSETIFF) failed (errno 1) > loop failed (errno 0) > > > tun: ioctl(TUNSETIFF) failed (errno 1) > loop failed (errno 0) > > > The system is Fedora 28 running the 4.18.16-200.fc28.x86_64 kernel. > What should I do to investigate further? Hi Alan, Looking at "errno 1", it seems that syz-execprog doesn't have enough privileges to execute this ioctl, so you might need to run it as root. However the absence of a C reproducer points to the fact that this is some kind of a race condition. Those are quite sensitive to timing, and any difference in the used setup might affect their reproducibility. I would recommend building the exact kernel revision with the provided config. For me it took around 3 minutes to syz-execprog before I saw the WARNING. Thanks!