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=-6.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 F12BAC4742C for ; Mon, 2 Nov 2020 12:23:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9B511223B0 for ; Mon, 2 Nov 2020 12:23:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="cxJBlz3R"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="WrVe6SPO" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728444AbgKBMXe (ORCPT ); Mon, 2 Nov 2020 07:23:34 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:58736 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728498AbgKBMXe (ORCPT ); Mon, 2 Nov 2020 07:23:34 -0500 Date: Mon, 2 Nov 2020 13:23:25 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1604319812; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=HgwwUY5/F2HnTzAMH5El6bOrIItG+nZNqxWdOrbFQQ8=; b=cxJBlz3RIkKPicwe3sk1tnKoPRoLj2Z8gT2pTQwCbnmc+O7p79jYRfF7ZgEg6NZyxpWPjs NjWuN5ptYZzts+070TJz/Jp/cLSCNLC5/BMXMuvKUVKbmWew63t8KRnkgeXpQK43V5hWw8 9N4R/TW8ci39T6Vo2sQwSgtJOPhZqezktAWCGnKFczOoRoX6QTBPCLwpTWXv7645YCDzAw KBMgkKwBjOM9Kx/zMw2JkYyETALtPcxo2yd6q9zevG7bSay0DBhWyZ5baY6YJfuEdoItUl yP8jluEPTtLuhq0bLBnwKl1H59r3iFunNCweWNU+pTHYmI1MM/VdkExPqd1tww== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1604319812; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=HgwwUY5/F2HnTzAMH5El6bOrIItG+nZNqxWdOrbFQQ8=; b=WrVe6SPOSZ7eICRe9EyQuREEZldZxfWwngJC3WfarvCfTLaaA6k7ql7B40deeDsTstltCe CA8KDmGnVExpytCg== From: Sebastian Andrzej Siewior To: Mike Galbraith Cc: linux-rt-users , Thomas Gleixner , Steven Rostedt Subject: Re: 5.10-rt: non-repeatable flush_delayed_work()...del_timer_wait_running() ATOMIC_SLEEP splat Message-ID: <20201102122325.pre6t4qo7bktrru2@linutronix.de> References: <20201030191853.raabwjou753fk4sh@linutronix.de> <17f055aad6788c17dbeb522f2cac4f8bb94f759b.camel@gmx.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <17f055aad6788c17dbeb522f2cac4f8bb94f759b.camel@gmx.de> Precedence: bulk List-ID: X-Mailing-List: linux-rt-users@vger.kernel.org On 2020-11-01 06:23:50 [+0100], Mike Galbraith wrote: > Apparently, timer ain't ever supposed to be running when you get there > via flush_delayed_work(), but it was. The first hunk will always trigger the warning and not just if the slow/wait path is really used. The second part should fix it. diff --git a/kernel/time/timer.c b/kernel/time/timer.c index 7edc9fba34bbd..696bb88d15db2 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -1372,6 +1372,13 @@ int del_timer_sync(struct timer_list *timer) */ WARN_ON(in_irq() && !(timer->flags & TIMER_IRQSAFE)); + /* + * Can not be used with disabled interrupts on PREEMPT_RT because + * del_timer_wait_running() sleeps. + */ + if (IS_ENABLED(CONFIG_PREEMPT_RT)) + WARN_ON(irqs_disabled()); + do { ret = try_to_del_timer_sync(timer); diff --git a/kernel/workqueue.c b/kernel/workqueue.c index c71da2a59e127..1ca03051a949f 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -3187,10 +3187,11 @@ EXPORT_SYMBOL_GPL(cancel_work_sync); */ bool flush_delayed_work(struct delayed_work *dwork) { - local_irq_disable(); - if (del_timer_sync(&dwork->timer)) + if (del_timer_sync(&dwork->timer)) { + local_irq_disable(); __queue_work(dwork->cpu, dwork->wq, &dwork->work); - local_irq_enable(); + local_irq_enable(); + } return flush_work(&dwork->work); } EXPORT_SYMBOL(flush_delayed_work); Sebastian