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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 73ECFC4332E for ; Fri, 20 Mar 2020 16:34:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 438CB20782 for ; Fri, 20 Mar 2020 16:34:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="u0naHVb/" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727479AbgCTQeQ (ORCPT ); Fri, 20 Mar 2020 12:34:16 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:43956 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727163AbgCTQeQ (ORCPT ); Fri, 20 Mar 2020 12:34:16 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=Content-Transfer-Encoding: Content-Type:In-Reply-To:MIME-Version:Date:Message-ID:From:References:Cc:To: Subject:Sender:Reply-To:Content-ID:Content-Description; bh=wn09ImmtyM/n6wRWgEQVs5UzpsZS8jQSQD4sGjfSADk=; b=u0naHVb/8v7hci/TU/GL9dHWyM MPMSsFGiPk757/dCPgmuplYGvS8HjskMzft6jCPCfq4NTZ33YMjqtwoR5Y7C1A65N24bPVlt/R6Z2 oJRxlOKcYtFxeq8ZCFGaYmOg8eV/gCPYFQxu/gqfqjSNEVKY5oq8GcAIbWui/qUD9u5Zbr1PKgkNP sojq33wlLeyyznoOhNTIcbJT2VeTGIHskJTAfVrDFc9hhhl4XZXXusuAYOeFzFOh6Cwf0OwyHm0mG X5oAKchOiY9Pu9yIqH5hQIrFXfMml7omH2gq6tdb8MbX9JJHFhG4ikqi0bWnGQhYUYDtiA7d9pae4 sjWE8W1w==; Received: from [2601:1c0:6280:3f0::19c2] by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jFKb8-00042l-6j; Fri, 20 Mar 2020 16:34:14 +0000 Subject: Re: linux-next build error (8) To: paulmck@kernel.org, Dmitry Vyukov Cc: syzbot , Josh Triplett , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Joel Fernandes , rcu@vger.kernel.org, LKML , syzkaller-bugs References: <000000000000ae2ab305a123f146@google.com> <20200318214109.GV3199@paulmck-ThinkPad-P72> <20200319150414.GD3199@paulmck-ThinkPad-P72> <20200320162650.GP3199@paulmck-ThinkPad-P72> From: Randy Dunlap Message-ID: Date: Fri, 20 Mar 2020 09:34:13 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <20200320162650.GP3199@paulmck-ThinkPad-P72> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: rcu-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org On 3/20/20 9:26 AM, Paul E. McKenney wrote: > On Fri, Mar 20, 2020 at 04:38:54PM +0100, Dmitry Vyukov wrote: >> On Thu, Mar 19, 2020 at 4:04 PM Paul E. McKenney wrote: >>> >>> On Thu, Mar 19, 2020 at 08:13:35AM +0100, Dmitry Vyukov wrote: >>>> On Wed, Mar 18, 2020 at 10:41 PM Paul E. McKenney wrote: >>>>> >>>>> On Wed, Mar 18, 2020 at 09:54:07PM +0100, Dmitry Vyukov wrote: >>>>>> On Wed, Mar 18, 2020 at 5:57 PM syzbot >>>>>> wrote: >>>>>>> >>>>>>> Hello, >>>>>>> >>>>>>> syzbot found the following crash on: >>>>>>> >>>>>>> HEAD commit: 47780d78 Add linux-next specific files for 20200318 >>>>>>> git tree: linux-next >>>>>>> console output: https://syzkaller.appspot.com/x/log.txt?x=14228745e00000 >>>>>>> kernel config: https://syzkaller.appspot.com/x/.config?x=b68b7b89ad96c62a >>>>>>> dashboard link: https://syzkaller.appspot.com/bug?extid=792dec47d693ccdc05a0 >>>>>>> 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+792dec47d693ccdc05a0@syzkaller.appspotmail.com >>>>>>> >>>>>>> kernel/rcu/tasks.h:1070:37: error: 'rcu_tasks_rude' undeclared (first use in this function); did you mean 'rcu_tasks_qs'? >>>>>> >>>>>> +rcu maintainers >>>>> >>>>> The kbuild test robot beat you to it, and apologies for the hassle. >>>>> Fixed in -rcu on current "dev" branch. >>>> >>>> If the kernel dev process would only have a way to avoid dups from all >>>> test systems... >>> >>> I do significant testing before pushing to -next, but triggering this >>> one requires a combination of Kconfig options that are incompatible >>> with rcutorture. :-/ >>> >>> I suppose one strategy would be to give kbuild test robot some time before >>> passing to -next, but they seem to sometimes get too far behind for me to >>> be willing to wait that long. So my current approach is to push my "dev" >>> branch, run moderate rcutorture testing (three hours per scenario other >>> than TREE10, which gets only one hour), and if that passes, push to -next. >>> >>> I suppose that I could push to -next only commits that are at least three >>> days old or some such. But I get in trouble pushing to -next too slowly >>> as often as I get in trouble pushing too quickly, so I suspect that my >>> current approach is in roughly the right place. >>> >>>> Now we need to spend time and deal with it. What has fixed it? >>> >>> It is fixed by commit c6ef38e4d595 ("rcu-tasks: Add RCU tasks to >>> rcutorture writer stall output") and some of its predecessors. >>> >>> Perhaps more useful to you, this commit is included in next-20200319 >>> from the -next tree. ;-) >> >> Let's tell syzbot about the fix: >> >> #syz fix: rcu-tasks: Add RCU tasks to rcutorture writer stall output >> >> I think what you are doing is the best possible option in the current situation. >> I don't think requiring all human maintainers to do more manual >> repetitive work, which is not well defined and even without a way to >> really require something from them is scalable nor reliable nor the >> right approach. > > Thank you, and I do greatly appreciate the automation! > >> We would consume something like LKGR [1] if it existed for the kernel. >> But it would require tighter integration of testing systems with >> kernel dev processes, or of course throwing more manual labor at it to >> track all uncoordinated testing systems and publishing LKGR tags. >> >> [1] https://chromium.googlesource.com/chromiumos/docs/+/master/glossary.md > > At my end, it is pretty quick and easy to detect duplicate notifications > of the same bug, so the current situation isn't causing me undue distress. Yeah, I saw the same build error and did-not-report it since it was already reported. :) -- ~Randy