Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756813AbaDWHOq (ORCPT ); Wed, 23 Apr 2014 03:14:46 -0400 Received: from www.linutronix.de ([62.245.132.108]:53355 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756687AbaDWHOo (ORCPT ); Wed, 23 Apr 2014 03:14:44 -0400 Message-ID: <53576859.8060706@linutronix.de> Date: Wed, 23 Apr 2014 09:14:33 +0200 From: Sebastian Andrzej Siewior User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Icedove/24.4.0 MIME-Version: 1.0 To: Steven Rostedt CC: Stanislav Meduna , "linux-rt-users@vger.kernel.org" , Linux ARM Kernel , "linux-kernel@vger.kernel.org" , Thomas Gleixner , Peter Zijlstra Subject: Re: BUG: spinlock trylock failure on UP, i.MX28 3.12.15-rt25 References: <534C3606.7010206@meduna.org> <534C731F.1050406@meduna.org> <534DADF1.6060608@meduna.org> <20140422115439.GA20669@linutronix.de> <20140422094657.5b6ca1e2@gandalf.local.home> <53569E05.8010600@linutronix.de> <20140422134802.73fc1fa4@gandalf.local.home> <20140422141650.7f43d5ba@gandalf.local.home> In-Reply-To: <20140422141650.7f43d5ba@gandalf.local.home> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/22/2014 08:16 PM, Steven Rostedt wrote: > --- a/kernel/timer.c > +++ b/kernel/timer.c > @@ -1447,6 +1447,12 @@ static void run_timer_softirq(struct softirq_action *h) > __run_timers(base); > } > > +#ifdef CONFIG_SMP > +#define timer_should_raise_softirq(lock) !spin_do_trylock(lock) > +#else > +#define timer_should_raise_softirq(lock) 1 > +#endif > + No. The lock may be taken but it also may be available no matter if UP or not. With this patch applied the lockdep splat will go away but the FULL_NO_HZ people will come back because the timer softirq is scheduled even if no timer has expired. Sebastian -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/