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=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_2 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 83230C56201 for ; Fri, 20 Nov 2020 19:28:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4A75422201 for ; Fri, 20 Nov 2020 19:28:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732374AbgKTT1j (ORCPT ); Fri, 20 Nov 2020 14:27:39 -0500 Received: from mail.kernel.org ([198.145.29.99]:43718 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729489AbgKTT1i (ORCPT ); Fri, 20 Nov 2020 14:27:38 -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 D2C75221F1; Fri, 20 Nov 2020 19:27:35 +0000 (UTC) Date: Fri, 20 Nov 2020 14:27:34 -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: <20201120142734.75af5cd6@gandalf.local.home> In-Reply-To: <20201119125357.GA2084963@elver.google.com> References: <20201111202153.GT517454@elver.google.com> <20201112001129.GD3249@paulmck-ThinkPad-P72> <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> 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 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. -- Steve diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 98d194d8460e..eb1dd9cf77a9 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -773,6 +773,8 @@ static void remove_event_file_dir(struct trace_event_file *file) kmem_cache_free(file_cachep, file); } +static int spam; + /* * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events. */ @@ -808,6 +810,8 @@ __ftrace_set_clr_event_nolock(struct trace_array *tr, const char *match, if (event && strcmp(event, name) != 0) continue; + if (spam) + printk("%s event %s\n", set ? "enabling" : "disabling", name); ret = ftrace_event_enable_disable(file, set); /* @@ -3647,6 +3651,7 @@ static __init void event_trace_self_tests(void) pr_info("Running tests on all trace events:\n"); pr_info("Testing all events: "); + spam = 1; ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1); if (WARN_ON_ONCE(ret)) { pr_warn("error enabling all events\n"); @@ -3661,6 +3666,7 @@ static __init void event_trace_self_tests(void) pr_warn("error disabling all events\n"); return; } + spam = 0; pr_cont("OK\n"); }