Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764887AbZAONj4 (ORCPT ); Thu, 15 Jan 2009 08:39:56 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757582AbZAONjq (ORCPT ); Thu, 15 Jan 2009 08:39:46 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:37155 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757293AbZAONjo (ORCPT ); Thu, 15 Jan 2009 08:39:44 -0500 Date: Thu, 15 Jan 2009 14:39:16 +0100 From: Ingo Molnar To: Tejun Heo Cc: roel kluin , "H. Peter Anvin" , Brian Gerst , ebiederm@xmission.com, cl@linux-foundation.org, rusty@rustcorp.com.au, travis@sgi.com, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, steiner@sgi.com, hugh@veritas.com Subject: Re: [patch] add optimized generic percpu accessors Message-ID: <20090115133916.GA3417@elte.hu> References: <496C9FB7.9050907@kernel.org> <496D8CEB.5060402@zytor.com> <20090114093834.GA19799@elte.hu> <25e057c00901150204x61c54d9fl91afe23477d1f12f@mail.gmail.com> <496F0F5E.3080404@kernel.org> <20090115113230.GH22850@elte.hu> <496F1FA6.6050204@kernel.org> <20090115122222.GI22850@elte.hu> <496F3577.4020303@kernel.org> <20090115133206.GA31416@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090115133206.GA31416@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 Content-Length: 1156 Lines: 30 * Ingo Molnar wrote: > FYI, -tip testing found the following bug with your percpu stuff: > > There's an early exception during bootup, on 64-bit x86: > > PANIC: early exception 0e rip 10:ffffffff80276855: error ? cr2 6688 > > - gcc version 4.3.2 20081007 (Red Hat 4.3.2-6) (GCC) > - binutils-2.18.50.0.6-2.x86_64 > > config attached. You can find the disassembly of lock_release_holdtime() > below - that's where it crashed: Gut feeling: we must have gotten a window where the PDA is not right. Note how it crashes in lock_release_holdtime() - that is CONFIG_LOCK_STAT instrumentation - very lowlevel and pervasive. Function tracing is also enabled although it should be inactive at the early stages. So i'd take a good look at the PDA setup portion of the boot code, and see whether some spinlock acquire/release can slip in while the PDA/percpu-area is not reliable. Ingo -- 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/