From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757271AbYIDOZy (ORCPT ); Thu, 4 Sep 2008 10:25:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752881AbYIDOZc (ORCPT ); Thu, 4 Sep 2008 10:25:32 -0400 Received: from casper.infradead.org ([85.118.1.10]:55154 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752412AbYIDOZb (ORCPT ); Thu, 4 Sep 2008 10:25:31 -0400 Subject: Re: [2.6.27] early exception - lockdep related? From: Peter Zijlstra To: Luca Tettamanti Cc: linux-kernel@vger.kernel.org, mingo@redhat.com In-Reply-To: <68676e00809031221v6486d4cdmc1ac7487acd01190@mail.gmail.com> References: <20080902210646.GA10925@dreamland.darkstar.lan> <1220424721.8609.74.camel@twins> <68676e00809030128o45820023n6f270847e14af2a3@mail.gmail.com> <68676e00809031221v6486d4cdmc1ac7487acd01190@mail.gmail.com> Content-Type: text/plain Date: Thu, 04 Sep 2008 16:25:31 +0200 Message-Id: <1220538332.8609.233.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2008-09-03 at 21:21 +0200, Luca Tettamanti wrote: > On Wed, Sep 3, 2008 at 10:28 AM, Luca Tettamanti wrote: > > On Wed, Sep 3, 2008 at 8:52 AM, Peter Zijlstra wrote: > >> On Tue, 2008-09-02 at 23:06 +0200, Luca Tettamanti wrote: > >>> Hello, > >>> I'm seeing an early exception (0e) - which seems related to lockdep - at > >>> boot with many 2.6.27 kernels and I'm having troubles to track it down. > >> > >> Does it print one of these nice stack traces? > > > > Of course not ;-) It dies before dumping the stack trace (or at least > > it doesn't make to the console - that machine has a serial port, but > > my notebook does not... I've ordered a usb-to-serial adapter). > > > >>> The strange thing is that it comes and goes with different kernel > >>> versions > >> > >> What kernel version did you generate the below with - and what config. > > > > -rc2 is working, after that it's intermittent. The last kernel that I > > tried is -git from a couple of days ago. > > > >>> , but a "bad" kernel consistently fails across reboots. It also > >>> seems to be sensitive to the configuration (attached) > >> > >> you seem to have forgotten that attachment. > > > > Ops, will send as soon as I get home. > > Config is attached. > > I tried netconsole, but got not output. No luck with qemu either :S > > QEMU from SVN reports that: > qemu: fatal: Trying to execute code outside RAM or ROM at 0x00000000000a0000 > > KVM goes a bit further but dies due to an exception while the kernel > is still executing in real mode. Sadly your config just boots, albeit not to userspace due to missing drivers. root@twins:/mnt/build/linux-2.6# git-describe v2.6.27-rc5-6-gbef69ea root@twins:/mnt/build/linux-2.6# /mnt/md0/cross/bin/x86_64-linux-gcc --version x86_64-linux-gcc (GCC) 4.3.1 20080510 (prerelease)