From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754772AbbCPOKZ (ORCPT ); Mon, 16 Mar 2015 10:10:25 -0400 Received: from www.linutronix.de ([62.245.132.108]:35454 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751989AbbCPOKV (ORCPT ); Mon, 16 Mar 2015 10:10:21 -0400 Message-ID: <5506E446.1060007@linutronix.de> Date: Mon, 16 Mar 2015 15:10:14 +0100 From: Sebastian Andrzej Siewior User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.5.0 MIME-Version: 1.0 To: Steven Rostedt CC: linux-kernel@vger.kernel.org, linux-rt-users , Thomas Gleixner , Carsten Emde , John Kacur , Paul Gortmaker Subject: Re: [PATCH RT 00/39] Linux 3.14.34-rt32-rc1 References: <20150312191307.081068717@goodmis.org> <20150316135910.GA28130@linutronix.de> <20150316100205.261c039e@gandalf.local.home> In-Reply-To: <20150316100205.261c039e@gandalf.local.home> Content-Type: text/plain; charset=windows-1252 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,URIBL_BLOCKED=0.001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/16/2015 03:02 PM, Steven Rostedt wrote: > On Mon, 16 Mar 2015 14:59:10 +0100 > Sebastian Andrzej Siewior wrote: > >> * Steven Rostedt | 2015-03-12 15:13:07 [-0400]: >> >>> Please scream at me if I messed something up. Please test the patches too. >> >> So Paul remided us about the dead lock thingy that has been reported. >> Users reported that it does not occur with v3.18-RT and they think it is >> due to 'Revert "timers: do not raise softirq unconditionally"' in >> Revert-timers-do-not-raise-softirq-unconditionally.patch. >> >> I reverted it because I couldn't get highres to get to work at all on >> v3.18 due to different synchronisation / expectaion of the timer >> framework. Since the trylock might record a different lock owner it is >> possible that this causes the deadlock (it thinks). Therefore it has no >> stable tag nor any reference to the deadlock problem. > > I guess the question is, is there any other place that does a trylock > in hard irq context? If so, the revert isn't going to fix it. This is the only place and I introduced it only for that reason. > > -- Steve Sebastian