From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756166AbZICS6W (ORCPT ); Thu, 3 Sep 2009 14:58:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754641AbZICS6V (ORCPT ); Thu, 3 Sep 2009 14:58:21 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:58096 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754350AbZICS6V (ORCPT ); Thu, 3 Sep 2009 14:58:21 -0400 Date: Thu, 3 Sep 2009 20:58:06 +0200 From: Ingo Molnar To: Thomas Gleixner Cc: Martin Schwidefsky , mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, johnstul@us.ibm.com, linux-tip-commits@vger.kernel.org Subject: Re: [boot crash] Re: [tip:timers/core] clocksource: Resolve cpu hotplug dead lock with TSC unstable Message-ID: <20090903185806.GA5949@elte.hu> References: <20090831101928.4c00c797@skybase> <20090903181743.GA22431@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090903181743.GA22431@elte.hu> User-Agent: Mutt/1.5.18 (2008-05-17) 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=3.2.5 -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: > i tried to bisect it but it's inconclusive: > > # bad: [32beef9c] Merge branch 'perfcounters/core' > # bad: [b6413360] manual merge of x86/platform > # bad: [d9e5f39a] Merge branch 'auto-oprofile-next' into auto-latest > # bad: [cbaff272] Merge branch 'auto-timers-next' into auto-latest > > as the bisection comes up with that merge commit. Perhaps the > combination of the x86/platform changes and the clocksource > changes triggered it? That seems to be the case - i just tested a combination merge of tip:auto-timers-next and tip:auto-x86-next and the result crashed in a similar way too. Since normal bisection cannot find such breakages, i did a topical bisection (merging the finegrained tip:x86/* topics into the timer tree gradually and testing each merge). That way i could exclude: x86/platform, x86/pat, x86/asm, x86/apic, x86/percpu, x86/cpu, x86/mm and arrived to x86/tsc - which contains a single commit: d3b8f88: x86: Make tsc=reliable override boot time stability checks Reverting that commit from tip:master gives me a non-crashing bootup. Ingo