From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753181AbaBZRYt (ORCPT ); Wed, 26 Feb 2014 12:24:49 -0500 Received: from mail.efficios.com ([78.47.125.74]:42604 "EHLO mail.efficios.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751716AbaBZRYs (ORCPT ); Wed, 26 Feb 2014 12:24:48 -0500 Date: Wed, 26 Feb 2014 17:24:47 +0000 (UTC) From: Mathieu Desnoyers To: Steven Rostedt Cc: Peter Zijlstra , LKML , Ingo Molnar , Rusty Russell , Frederic Weisbecker , Andrew Morton Message-ID: <339841817.31009.1393435487685.JavaMail.zimbra@efficios.com> In-Reply-To: <20140226111542.15657cd6@gandalf.local.home> References: <20140225191505.32b56105@gandalf.local.home> <188130295.30493.1393375141631.JavaMail.zimbra@efficios.com> <20140225194926.4eac5872@gandalf.local.home> <20140226085926.GF18404@twins.programming.kicks-ass.net> <192956891.30659.1393418892222.JavaMail.zimbra@efficios.com> <20140226111542.15657cd6@gandalf.local.home> Subject: Re: [RFC][PATCH] tracing: Warn and notify if tracepoints are not loaded due to module taint MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [206.248.138.119] X-Mailer: Zimbra 8.0.5_GA_5839 (ZimbraWebClient - FF27 (Linux)/8.0.5_GA_5839) Thread-Topic: tracing: Warn and notify if tracepoints are not loaded due to module taint Thread-Index: wRlfhXC2k93erj3krVcQ33U0TyX1Xw== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ----- Original Message ----- > From: "Steven Rostedt" > To: "Mathieu Desnoyers" > Cc: "Peter Zijlstra" , "LKML" , "Ingo Molnar" , > "Rusty Russell" , "Frederic Weisbecker" , "Andrew Morton" > > Sent: Wednesday, February 26, 2014 11:15:42 AM > Subject: Re: [RFC][PATCH] tracing: Warn and notify if tracepoints are not loaded due to module taint > > On Wed, 26 Feb 2014 12:48:12 +0000 (UTC) > Mathieu Desnoyers wrote: > > > > How about instead of a WARN, you use a normal KERN_ERR printk(). There's > > > no point to the entire WARN state dump, that's needlessly verbose. > > > > > > When you have a normal error print you can have as many as are required > > > and put the mod name back in. > > > > The good old printk KERN_ERR is a very good idea. I agree that WARN() is > > too verbose for our needs here. > > Actually, it's not so bad for the WARN() after my last patch to only > allocate (or even process tracepoints) if mod->num_tracepionts is > greater than zero. I didn't realize you were wasting memory for all > modules that were loaded. > > My fear with the KERN_ERR is that it wont be noticeable enough. Where > as a stack dump is something that will catch people's attention. > > And as Rusty has said, if you are loading a module that is forced, or > something strange, it is broken. The failure of loading the tracepoints > of a module is a bug if the module happens to have tracepoints. > > After the MOD_SIG fix, any failure should be a big banner bug. Either > they are using a forced module with tracepoints that should not be > loaded. Or they have tracepoints is a non-GPL module (which is also a > big no-no). Agreed that after the skip for modules containing 0 tracepoints, it gets much more specific. I like that. So then a WARN_ON() that prints the specific module name involved would be the way to go ? Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com