Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756169Ab3GKQza (ORCPT ); Thu, 11 Jul 2013 12:55:30 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:32988 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756057Ab3GKQz1 (ORCPT ); Thu, 11 Jul 2013 12:55:27 -0400 X-Authority-Analysis: v=2.0 cv=Du3UCRD+ c=1 sm=0 a=Sro2XwOs0tJUSHxCKfOySw==:17 a=Drc5e87SC40A:10 a=mY5AGG0wUPsA:10 a=5SG0PmZfjMsA:10 a=IkcTkHD0fZMA:10 a=meVymXHHAAAA:8 a=KGjhK52YXX0A:10 a=x45eBLDEq7QA:10 a=SlZC6DwobfxERQ2Y5Y4A:9 a=QEXdDO2ut3YA:10 a=Sro2XwOs0tJUSHxCKfOySw==:117 X-Cloudmark-Score: 0 X-Authenticated-User: X-Originating-IP: 67.255.60.225 Message-ID: <1373561726.17876.48.camel@gandalf.local.home> Subject: Re: timer: lockup in run_timer_softirq() From: Steven Rostedt To: Peter Zijlstra Cc: Sasha Levin , Dave Jones , Tejun Heo , tglx@linutronix.de, LKML , trinity@vger.kernel.org Date: Thu, 11 Jul 2013 12:55:26 -0400 In-Reply-To: <20130711164204.GK25631@dyad.programming.kicks-ass.net> References: <51DC902F.3070403@oracle.com> <20130709224706.GA13855@redhat.com> <51DC9379.9050408@oracle.com> <20130709230316.GB13855@redhat.com> <51DC983F.2010409@oracle.com> <20130710095210.GD17211@twins.programming.kicks-ass.net> <1373459254.7458.49.camel@gandalf.local.home> <20130710124245.GT25631@dyad.programming.kicks-ass.net> <1373461091.7458.55.camel@gandalf.local.home> <20130711164204.GK25631@dyad.programming.kicks-ass.net> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.4.4-3 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 891 Lines: 26 On Thu, 2013-07-11 at 18:42 +0200, Peter Zijlstra wrote: > I'm afraid this is going to be hard to create and hard to keep correct :/ That's the nature of tracing functions ;-) > > Other than that, a function tracer environment that is safer to use might be > useful for other people as well. Not sure how to make the environment safe, as the main purpose of the function trace is to debug those hard to debug locations, like NMIs, RCU, dynamic ticks, etc. To ensure a "safe" environment, it would cripple the tracer. Hmm, what would you state as a safe environment? How can we detect if the environment is safe to trace or not? -- Steve -- 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/