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 Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C602CC433EF for ; Fri, 8 Apr 2022 01:43:46 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4KZLcx0dqqz3050 for ; Fri, 8 Apr 2022 11:43:45 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=OZIjTu/W; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=2604:1380:4601:e00::1; helo=ams.source.kernel.org; envelope-from=srs0=khno=us=paulmck-thinkpad-p17-gen-1.home=paulmck@kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=OZIjTu/W; dkim-atps=neutral Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4KZLcC47Klz2yHB for ; Fri, 8 Apr 2022 11:43:07 +1000 (AEST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 5C5A2B8299C; Fri, 8 Apr 2022 01:43:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0271EC385A0; Fri, 8 Apr 2022 01:43:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1649382182; bh=HKAa0zZ+YfScnYiwonuO4THcQaAZWiT7gougIGWPYSU=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=OZIjTu/W8oyNhG7ciPLsXIUYQr/zfuV1qyJvoXYCBH3Iv2heRTzrYvwKHurqFC/Ic eiXcKvcIuW+bqpYF2Gj5Kd5uKV8Mr2Xi87W0EP6r99NzpgMLXepBi7R0zNR29MshIU Qi80nBKgY+DPm15BkU4VXJb6u1hzU7pArGFCOtyFLaG5NojJBDRAyNAA01crWhzeHz bDP99uvYWL0mKb5STI4F5A4kWNGrTo/1t6jHhC2UFGB8Kzy/8kkRgSlNEpMlDcthRm zgU1z9Y4jT5vfdD/QXMlLIBio9n0SbMMWK7KaaTgweIzhiyUdZLmomahQ2mzpBj26n CI0WVfmDKoUcA== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id 9E7F65C04BE; Thu, 7 Apr 2022 18:43:01 -0700 (PDT) Date: Thu, 7 Apr 2022 18:43:01 -0700 From: "Paul E. McKenney" To: Zhouyi Zhou Subject: Re: rcu_sched self-detected stall on CPU Message-ID: <20220408014301.GW4285@paulmck-ThinkPad-P17-Gen-1> References: <20220406170012.GO4285@paulmck-ThinkPad-P17-Gen-1> <20220406195011.GP4285@paulmck-ThinkPad-P17-Gen-1> <20220407151555.GR4285@paulmck-ThinkPad-P17-Gen-1> <20220407175500.GV4285@paulmck-ThinkPad-P17-Gen-1> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: paulmck@kernel.org Cc: rcu , Miguel Ojeda , linuxppc-dev Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Fri, Apr 08, 2022 at 07:14:20AM +0800, Zhouyi Zhou wrote: > Dear Paul and Miguel > > On Fri, Apr 8, 2022 at 1:55 AM Paul E. McKenney wrote: > > > > On Thu, Apr 07, 2022 at 07:05:58PM +0200, Miguel Ojeda wrote: > > > On Thu, Apr 7, 2022 at 5:15 PM Paul E. McKenney wrote: > > > > > > > > Ah. So you would instead look for boot to have completed within 10 > > > > seconds? Either way, reliable automation might well more important than > > > > reduction in time. > > > > > > No (although I guess that could be an option), I was only pointing out > > > that when no stall is produced, the run should be much quicker than 30 > > > seconds (at least it was in my setup), which would be the majority of the runs. > > > > Ah, thank you for the clarification! > Thank both of you for the information. In my setup (PPC cloud VM), the > majority of the runs complete at least for 50 seconds. From last > evening to this morning (Beijing Time), following experiments have > been done: > 1) torture mainline: the test quickly finished by hitting "rcu_sched > self-detected stall" after 12 runs > 2) torture v5.17: the test last 10 hours plus 14 minutes, 702 runs > have been done without trigger the bug > > Conclusion: > There must be a commit that causes the bug as Paul has pointed out. > I am going to do the bisect, and estimate to locate the bug within a > week (at most). > This is a good learning experience, thanks for the guidance ;-) Very good, and looking forward to seeing what you find. Thanx, Paul