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=-16.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS 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 AC0DEC433B4 for ; Fri, 7 May 2021 17:13:03 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 1B7E1610CD for ; Fri, 7 May 2021 17:13:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1B7E1610CD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 2AA868D001B; Fri, 7 May 2021 13:13:02 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2597A8D001A; Fri, 7 May 2021 13:13:02 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0FB6A8D001B; Fri, 7 May 2021 13:13:02 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0211.hostedemail.com [216.40.44.211]) by kanga.kvack.org (Postfix) with ESMTP id E03688D001A for ; Fri, 7 May 2021 13:13:01 -0400 (EDT) Received: from smtpin38.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id AC809B798 for ; Fri, 7 May 2021 17:13:01 +0000 (UTC) X-FDA: 78115080162.38.1D64FE5 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf29.hostedemail.com (Postfix) with ESMTP id 6BF383DB for ; Fri, 7 May 2021 17:12:55 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 1CE5C610CD; Fri, 7 May 2021 17:13:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1620407580; bh=zFapcfGOgC3O/0mNO723wBmbSDDp4RZDLXU57riBmLU=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=DYR3SASqhtUsxrXUtZJPoGsi/CrYhaJAUjVKpAvO8w2AaIpMG9nHvU7/FxiskJAfe amI5SSXE3GIUyON29Eei0AZCpgkGu0rcc52wOQ4IPsburunq8QSyXFEaNYsf2LKrlS Y3v+fHun7vc3Aq9UBT6ssrN3a7Xv7MfjW4hwzunOlZ0sYCAFwE5EX4Dndsjcwjl5UL mSg/RGrv1XHVFo2f6fqEGBMQOPOqrMOzK6r1UxtY4ym81fO+nANU1IKW79Bu/WrHoX YyVCeEBeOr3s9m0VoCZneUA1PLIc+N9SLJkVvmmNsFJngSvkJar2snTcEWBF2DT0nM TX+Wbg7kITQzg== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id A1CBE5C0293; Fri, 7 May 2021 10:12:59 -0700 (PDT) Date: Fri, 7 May 2021 10:12:59 -0700 From: "Paul E. McKenney" To: kernel test robot Cc: Thomas Gleixner , John Stultz , Stephen Boyd , Jonathan Corbet , Mark Rutland , Marc Zyngier , Andi Kleen , Feng Tang , Xing Zhengjun , Chris Mason , LKML , Linux Memory Management List , lkp@lists.01.org, lkp@intel.com Subject: Re: [clocksource] 8e614d5b58: WARNING:at_kernel/time/clocksource-wdtest.c:#wdtest_func.cold Message-ID: <20210507171259.GA236800@paulmck-ThinkPad-P17-Gen-1> Reply-To: paulmck@kernel.org References: <20210505143616.GC9038@xsang-OptiPlex-9020> <20210505180312.GM975577@paulmck-ThinkPad-P17-Gen-1> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210505180312.GM975577@paulmck-ThinkPad-P17-Gen-1> X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 6BF383DB X-Stat-Signature: bdbffkqesrgk4ygtunfnq6m7c4q4ri74 Authentication-Results: imf29.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=DYR3SASq; spf=pass (imf29.hostedemail.com: domain of "SRS0=mWbO=KC=paulmck-ThinkPad-P17-Gen-1.home=paulmck@kernel.org" designates 198.145.29.99 as permitted sender) smtp.mailfrom="SRS0=mWbO=KC=paulmck-ThinkPad-P17-Gen-1.home=paulmck@kernel.org"; dmarc=pass (policy=none) header.from=kernel.org Received-SPF: none (kernel.org>: No applicable sender policy available) receiver=imf29; identity=mailfrom; envelope-from=""; helo=mail.kernel.org; client-ip=198.145.29.99 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1620407575-807737 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, May 05, 2021 at 11:03:12AM -0700, Paul E. McKenney wrote: > On Wed, May 05, 2021 at 10:36:16PM +0800, kernel test robot wrote: > > > > > > Greeting, > > > > FYI, we noticed the following commit (built with gcc-9): > > > > commit: 8e614d5b58992e722f07de7c2426f2c44668092b ("clocksource: Provide kernel module to test clocksource watchdog") > > https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git master > > > > > > in testcase: boot > > > > on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G > > > > caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): > > > > > > +-------------------------------------------------------------------------+------------+------------+ > > | | bdbd9c673e | 8e614d5b58 | > > +-------------------------------------------------------------------------+------------+------------+ > > | WARNING:at_kernel/time/clocksource-wdtest.c:#wdtest_func.cold | 0 | 11 | > > | RIP:wdtest_func.cold | 0 | 11 | > > +-------------------------------------------------------------------------+------------+------------+ > > Might it be useful to address the lockdep issues that preceded this splat? > > Leaving that aside, the system appears to still be booting. There are > RCU CPU stall warning messages later on, and then the system hangs more > than six minutes while still booting, presumably due to the large number > of self-tests and debug options enabled. > > The intent is that the clocksource-wdtest tests run after boot has > completed. One approach would be to test it using modprobe after boot > has completed. In addition, the clocksource-wdtest module is not designed > to handle CPU overload conditions, and making it do so would reduce the > effectiveness of the test. > > I suggest setting clocksource-wdtest.holdoff=N, where "N" is in seconds > and is large enough that boot has completed. Alternatively, use modprobe > to activate this module from userspace after boot has completed. > > What I do is just set CONFIG_TEST_CLOCKSOURCE_WATCHDOG=y in an ordinary > rcutorture run, if that helps. All that aside, does the patch below help in your environment? If so, I can adjust so that my testing gets done quickly and yours avoids false-positive failures. Thanx, Paul ------------------------------------------------------------------------ diff --git a/kernel/time/clocksource-wdtest.c b/kernel/time/clocksource-wdtest.c index 01df12395c0e..0d8542f8b1d2 100644 --- a/kernel/time/clocksource-wdtest.c +++ b/kernel/time/clocksource-wdtest.c @@ -149,7 +149,7 @@ static int wdtest_func(void *arg) s = ", expect clock skew"; pr_info("--- Watchdog with %dx error injection, %lu retries%s.\n", i, max_cswd_read_retries, s); WRITE_ONCE(wdtest_ktime_read_ndelays, i); - schedule_timeout_uninterruptible(2 * HZ); + schedule_timeout_uninterruptible(60 * HZ); WARN_ON_ONCE(READ_ONCE(wdtest_ktime_read_ndelays)); WARN_ON_ONCE((i <= max_cswd_read_retries) != !(clocksource_wdtest_ktime.flags & CLOCK_SOURCE_UNSTABLE));