From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761305AbYGJSIr (ORCPT ); Thu, 10 Jul 2008 14:08:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760577AbYGJSHT (ORCPT ); Thu, 10 Jul 2008 14:07:19 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:35783 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760566AbYGJSHR (ORCPT ); Thu, 10 Jul 2008 14:07:17 -0400 Date: Thu, 10 Jul 2008 20:06:20 +0200 From: Ingo Molnar To: Linus Torvalds Cc: Alexey Dobriyan , Nick Piggin , "Rafael J. Wysocki" , Kamalesh Babulal , "Paul E. McKenney" , Linux Kernel Mailing List , Adrian Bunk , Andrew Morton , Natalie Protasevich , Kernel Testers List , "Paul E. McKenney" Subject: Re: 2.6.26-rc9-git4: Reported regressions from 2.6.25 Message-ID: <20080710180620.GA30844@elte.hu> References: <4yrA-dRoNlD.A.jcB.ny-cIB@albercik> <200807101725.36175.nickpiggin@yahoo.com.au> <20080710110213.GA6688@martell.zuzino.mipt.ru> <20080710173459.GA11648@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080710173459.GA11648@elte.hu> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Ingo Molnar wrote: > cool! :) > > (hm, could anyone please resend Nick's original mail? The original one > is not in my lkml folder nor on lkml.org - only the quoted one.) ok, got the mail now now: | | Annoyed this wasn't a crazy obscure error in the algorithm I could | | fix :) [...] Paul recently ran a formal proof against all sorts of RCU details (and found and fixed a few obscure races that way that no-one ever triggered), so i'd be quite surprised if we found anything in the core algorithm :-) | | [...] I spent all day debugging it and had to make a special test | | case (rcutorture didn't seem to trigger it), and a big RCU state | | logging infrastructure to log millions of RCU state transitions and | | events. Oh well. nice debugging! Acked-by: Ingo Molnar i'm wondering why rcutorture didnt trigger it. I do run !HOTPLUG + RCU_PREEMPT kernels and never saw this. Nor did Paul. That aspect is weird. Ingo