Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933262AbZAOVzx (ORCPT ); Thu, 15 Jan 2009 16:55:53 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932663AbZAOVzN (ORCPT ); Thu, 15 Jan 2009 16:55:13 -0500 Received: from hera.kernel.org ([140.211.167.34]:55964 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932694AbZAOVzK (ORCPT ); Thu, 15 Jan 2009 16:55:10 -0500 Message-ID: <496FB09A.8020808@kernel.org> Date: Fri, 16 Jan 2009 06:54:34 +0900 From: Tejun Heo User-Agent: Thunderbird 2.0.0.19 (X11/20081227) MIME-Version: 1.0 To: Ingo Molnar 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 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> <20090115133916.GA3417@elte.hu> In-Reply-To: <20090115133916.GA3417@elte.hu> X-Enigmail-Version: 0.95.7 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.0 (hera.kernel.org [127.0.0.1]); Thu, 15 Jan 2009 21:54:38 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1332 Lines: 36 Hello, Ingo. Ingo Molnar wrote: > * 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. Heh... I tought I got this covered pretty good. I'll get onto debugging in a few hours. Thanks for testing. -- tejun -- 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/