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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 560CDC4321D for ; Fri, 17 Aug 2018 18:22:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E786D21A2F for ; Fri, 17 Aug 2018 18:22:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E786D21A2F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=xmission.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 S1727783AbeHQV1U (ORCPT ); Fri, 17 Aug 2018 17:27:20 -0400 Received: from out02.mta.xmission.com ([166.70.13.232]:55724 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726888AbeHQV1T (ORCPT ); Fri, 17 Aug 2018 17:27:19 -0400 Received: from in01.mta.xmission.com ([166.70.13.51]) by out02.mta.xmission.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.87) (envelope-from ) id 1fqjOg-0000Bf-GN; Fri, 17 Aug 2018 12:22:54 -0600 Received: from [97.119.167.31] (helo=x220.xmission.com) by in01.mta.xmission.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.87) (envelope-from ) id 1fqjOQ-0004qD-Ts; Fri, 17 Aug 2018 12:22:54 -0600 From: ebiederm@xmission.com (Eric W. Biederman) To: Dmitry Vyukov Cc: "J. Bruce Fields" , Stephen Rothwell , syzbot , jlayton@kernel.org, linux-fsdevel , LKML , syzkaller-bugs , Al Viro References: <0000000000007f59610573509684@google.com> <000000000000f4136d0573512103@google.com> <20180814191129.GN7906@fieldses.org> <87o9e3gdtg.fsf@xmission.com> Date: Fri, 17 Aug 2018 13:22:31 -0500 In-Reply-To: (Dmitry Vyukov's message of "Fri, 17 Aug 2018 10:26:58 -0700") Message-ID: <87d0ugc0pk.fsf@xmission.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1fqjOQ-0004qD-Ts;;;mid=<87d0ugc0pk.fsf@xmission.com>;;;hst=in01.mta.xmission.com;;;ip=97.119.167.31;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX19RM6ezQkXV4F6Ej3djQ7NVGUxG2Nk5/q0= X-SA-Exim-Connect-IP: 97.119.167.31 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: Re: general protection fault in send_sigurg_to_task X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in01.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Dmitry Vyukov writes: > On Wed, Aug 15, 2018 at 9:01 PM, Eric W. Biederman > wrote: >> Dmitry Vyukov writes: >> >>> On Tue, Aug 14, 2018 at 12:11 PM, J. Bruce Fields wrote: >>>> On Mon, Aug 13, 2018 at 06:33:02AM -0700, syzbot wrote: >>>>> syzbot has found a reproducer for the following crash on: >>>>> >>>>> HEAD commit: 5ed5da74de9e Add linux-next specific files for 20180813 >>>>> git tree: linux-next >>>> >>>> I fetched linux-next but don't have 5ed5da74de9e. >>> >>> Hi Bruce, >>> >>> +Stephen for the disappeared linux-next commit. >>> >>> On the dashboard link you can see that it also happened on a more >>> recent commit 4e8b38549b50459a22573d756dd1f4e1963c2a8d that I do see >>> now in linux-next. >>> >>>> I'm also not sure why I'm on the cc for this. >>> >>> You've been pointed to by "./scripts/get_maintainer.pl -f fs/fcntl.c" >>> as maintainer of the file, which is the file where the crash happened. >> >> You need to use your reproducer to bisect and find the commit that >> caused this. Otherwise you will continue to confuse people. >> >> get_maintainer.pl is not a good target for automated reporting >> especially against linux-next. > > Hi Eric, > > We will do bisection. > But I afraid it will not give perfect attribution for a number of reasons: > - broken build/boot which happens sometimes for prolonged periods and > prohibits bisection > - elusive races that can't be reproduced reliably and thus bisection > can give wrong results > - bugs introduced too long ago (e.g. author email is not even valid today) > - reproducers triggering more than 1 bug, so base bisection commit > can actually be for another bug, or bisection can switch from one bug > to another > - last but not least, bugs without reproducers > Bisection will add useful information to the bug report, but it will > not necessary make attribution better than it is now. > > Do you have more examples where bugs were misreported? From what I see > current attrition works well. There are episodic fallouts, but well, > nothing is perfect in this world. Humans don't bisect frequently and > misreport sometimes. I think we just need to re-route bugs in such > cases. I have yet to see syzbot make a good report. Especially against linux-next. Eric