Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753433AbbEZNHM (ORCPT ); Tue, 26 May 2015 09:07:12 -0400 Received: from [62.245.222.98] ([62.245.222.98]:53606 "EHLO mail.bmw-carit.de" rhost-flags-FAIL-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752825AbbEZNHJ (ORCPT ); Tue, 26 May 2015 09:07:09 -0400 X-CTCH-RefID: str=0001.0A0C0202.55646C50.023A,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0 Message-ID: <55646C50.7070106@bmw-carit.de> Date: Tue, 26 May 2015 14:51:28 +0200 From: Daniel Wagner User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Steven Rostedt CC: Ingo Molnar , Peter Zijlstra , "linux-kernel@vger.kernel.org" Subject: Re: lockdep warning: threadirqs and preemptoff tracer References: <555C49D8.8030009@bmw-carit.de> <55645E62.2070507@bmw-carit.de> <20150526083215.28f3374b@gandalf.local.home> In-Reply-To: <20150526083215.28f3374b@gandalf.local.home> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1225 Lines: 28 On 05/26/2015 02:32 PM, Steven Rostedt wrote: > Daniel Wagner wrote: >> On 05/20/2015 10:46 AM, Daniel Wagner wrote: >> I starred for a while at the code and saw the comment in >> __local_bh_disable_ip(): >> >> /* >> * The preempt tracer hooks into preempt_count_add and will break >> * lockdep because it calls back into lockdep after SOFTIRQ_OFFSET >> * is set and before current->softirq_enabled is cleared. >> * We must manually increment preempt_count here and manually >> * call the trace_preempt_off later. >> */ >> >> >From this I figured this might be the same problem just in the >> enable path. The below patch made the lockdep warning disappear. >> Though I am not sure what I breaking with this. > > Don't you want to modify __local_bh_enable_ip()? __do_softirq() calls __local_bh_disable_ip() and __local_bh_enable() and not __local_bh_enable_ip(). I have no clue why this is done this way. Need to look into the history. -- 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/