From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934041Ab0D3Sdk (ORCPT ); Fri, 30 Apr 2010 14:33:40 -0400 Received: from fallback.mail.elte.hu ([157.181.151.13]:46255 "EHLO fallback.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934030Ab0D3Sdd (ORCPT ); Fri, 30 Apr 2010 14:33:33 -0400 Date: Fri, 30 Apr 2010 12:07:49 +0200 From: Ingo Molnar To: "Paul E. McKenney" Cc: linux-kernel@vger.kernel.org, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca, josh@joshtriplett.org, dvhltc@us.ibm.com, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, Valdis.Kletnieks@vt.edu, dhowells@redhat.com, eric.dumazet@gmail.com Subject: Re: [PATCH tip/core/urgent] fix several lockdep splats, allow multiple splats Message-ID: <20100430100749.GC14202@elte.hu> References: <20100421200150.GA3818@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100421200150.GA3818@linux.vnet.ibm.com> User-Agent: Mutt/1.5.20 (2009-08-17) X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.5 -2.0 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0007] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Paul E. McKenney wrote: > Hello! > > This patchset contains four RCU lockdep splat fixes, courtesy of David > Howells, Peter Zijlstra, and Trond Myklebust, [...] I've applied #1 and #2 - but shouldnt #4 and #5 go via the NFS tree? > [...] as well as an enhancement by Lai Jiangshan that permits collecting > more than one RCU lockdep splat per boot. Hm, this #3 patch i disagree with quite fundamentally: one of the big virtues of lockdep is that it complains only once and then shuts up and lets the system work. It allows distro debug kernels to have lockdep enabled, etc. One bugreport per bootup per user is the most we can expect really. Not disabling it risks getting a stream of repeat messages, annoyed testers and gives us _less_ bugreports in the end. Also, often the _first_ warning is the most reliable one - sometimes there's interactions, and the first bug causing a second warning as well, etc. So reporting just the highest-quality (i.e. first) issue we detect is the best approach. Thanks, Ingo