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[23.128.96.18]) by mx.google.com with ESMTP id wr19si6604783ejb.218.2020.11.23.08.32.01; Mon, 23 Nov 2020 08:32:24 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387664AbgKWQ2R (ORCPT + 99 others); Mon, 23 Nov 2020 11:28:17 -0500 Received: from mail.kernel.org ([198.145.29.99]:55678 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732677AbgKWQ2R (ORCPT ); Mon, 23 Nov 2020 11:28:17 -0500 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7106E20644; Mon, 23 Nov 2020 16:28:14 +0000 (UTC) Date: Mon, 23 Nov 2020 11:28:12 -0500 From: Steven Rostedt To: Marco Elver Cc: "Paul E. McKenney" , Anders Roxell , Andrew Morton , Alexander Potapenko , Dmitry Vyukov , Jann Horn , Mark Rutland , Linux Kernel Mailing List , Linux-MM , kasan-dev , rcu@vger.kernel.org, Peter Zijlstra , Tejun Heo , Lai Jiangshan Subject: Re: [PATCH] kfence: Avoid stalling work queue task without allocations Message-ID: <20201123112812.19e918b3@gandalf.local.home> In-Reply-To: <20201123152720.GA2177956@elver.google.com> References: <20201112161439.GA2989297@elver.google.com> <20201112175406.GF3249@paulmck-ThinkPad-P72> <20201113175754.GA6273@paulmck-ThinkPad-P72> <20201117105236.GA1964407@elver.google.com> <20201117182915.GM1437@paulmck-ThinkPad-P72> <20201118225621.GA1770130@elver.google.com> <20201118233841.GS1437@paulmck-ThinkPad-P72> <20201119125357.GA2084963@elver.google.com> <20201120142734.75af5cd6@gandalf.local.home> <20201123152720.GA2177956@elver.google.com> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 23 Nov 2020 16:27:20 +0100 Marco Elver wrote: > On Fri, Nov 20, 2020 at 02:27PM -0500, Steven Rostedt wrote: > > On Thu, 19 Nov 2020 13:53:57 +0100 > > Marco Elver wrote: > > > > > Running tests again, along with the function tracer > > > Running tests on all trace events: > > > Testing all events: > > > BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 12s! > > > > The below patch might be noisy, but can you add it to the kernel that > > crashes and see if a particular event causes the issue? > > > > [ note I didn't even compile test. I hope it works ;) ] > > > > Perhaps run it a couple of times to see if it crashes on the same set of > > events each time. > > Thanks! I have attached the logs of 2 runs. I think one problem here is > that the enabling of an event doesn't immediately trigger the problem, > so it's hard to say which one caused it. > I noticed: [ 237.650900] enabling event benchmark_event In both traces. Could you disable CONFIG_TRACEPOINT_BENCHMARK and see if the issue goes away. That event kicks off a thread that spins in a tight loop for some time and could possibly cause some issues. It still shouldn't break things, we can narrow it down if it is the culprit. -- Steve