From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965175AbXGSRB1 (ORCPT ); Thu, 19 Jul 2007 13:01:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965170AbXGSRBO (ORCPT ); Thu, 19 Jul 2007 13:01:14 -0400 Received: from cantor2.suse.de ([195.135.220.15]:35757 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965138AbXGSRBM (ORCPT ); Thu, 19 Jul 2007 13:01:12 -0400 From: Andi Kleen Organization: SUSE Linux Products GmbH, Nuernberg, GF: Markus Rex, HRB 16746 (AG Nuernberg) To: "Pekka Enberg" Subject: Re: kmalloc zero size changes break i386 Date: Thu, 19 Jul 2007 19:01:06 +0200 User-Agent: KMail/1.9.6 Cc: "Christoph Lameter" , torvalds@osdl.org, linux-kernel@vger.kernel.org References: <200707191201.35777.ak@suse.de> <84144f020707190708p1c4d63cnbb0397a602c3527d@mail.gmail.com> In-Reply-To: <84144f020707190708p1c4d63cnbb0397a602c3527d@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200707191901.06492.ak@suse.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thursday 19 July 2007 16:08:34 Pekka Enberg wrote: > Hi Andi, > > On 7/19/07, Andi Kleen wrote: > > qemu testing and booting test machines with i386 kernels wasn't very successfull > > with recent git kernels. I got either BUGs because of failing sysfs initialization > > or oopses in kmalloc, but no user land. > > > > I bisected it down to this commit. > > > > To reproduce: try to boot a 386 defconfig kernel, compiled with gcc 4.1, in qemu > > [snip] > > > 6cb8f91320d3e720351c21741da795fed580b21b is first bad commit > > commit 6cb8f91320d3e720351c21741da795fed580b21b > > Author: Christoph Lameter > > Date: Tue Jul 17 04:03:22 2007 -0700 > > > > Slab allocators: consistent ZERO_SIZE_PTR support and NULL result semantics > > I have i386 defconfig kernel + qemu + busybox userland image + GCC > 4.1.2 booting ok here. Did you manage to capture the oops? The sysfs crashes are all over; the first I saw is the BUG_ON() in kernel_param_sysfs_setup(); but it was changing during the bisect and in other similar sysfs BUG_ON()s too. During one bisect state I also had a crash in kmalloc itself. I right now don't have it anymore; do you want me to restart the bisect go recreate it? x86-64 kernels BTW work just fine; just something seems to be broken with i386. Unfortunately newsetup seems to have broken argument passing to qemu so it's a bit difficult to get more out of it. > Is the > userland image available somewhere? Userland is not reached yet. You can just use a dummy dd if=/dev/zero of=.... bs=1M count=1 file. -Andi