Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754014Ab1BPUQD (ORCPT ); Wed, 16 Feb 2011 15:16:03 -0500 Received: from smtp1.linux-foundation.org ([140.211.169.13]:58357 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752194Ab1BPUP7 (ORCPT ); Wed, 16 Feb 2011 15:15:59 -0500 MIME-Version: 1.0 In-Reply-To: References: <20110216185234.GA11636@tiehlicka.suse.cz> <20110216193700.GA6377@elte.hu> From: Linus Torvalds Date: Wed, 16 Feb 2011 12:09:35 -0800 Message-ID: Subject: Re: BUG: Bad page map in process udevd (anon_vma: (null)) in 2.6.38-rc4 To: Ingo Molnar Cc: Michal Hocko , linux-mm@kvack.org, LKML Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1503 Lines: 37 On Wed, Feb 16, 2011 at 11:50 AM, Linus Torvalds wrote: > > Yup, goodie. It does look like it might be exactly the same thing, > except now the offset seems to be 0x1e68 instead of 0x1768. It was 0x1748 in Eric's case. Background for Michal: http://lkml.org/lkml/2011/2/14/223 Michal - if you can re-create this, it would be wonderful if you can enable CONFIG_DEBUG_PAGEALLOC. I didn't find any obvious candidates yet. Also, what is a bit surprising is that the x86-32 offset is bigger than the x86-64 one. Normally the x86-64 structures are much bigger due to the obvious 64-bit fields. I wonder if it's something counting backwards from the top. IOW, it could be a "list_init()" on the kernel stack (which is 8kB - see THREAD_ORDER) after the stack has been released. That would explain why the offset is bigger on x86-32, because it's simply closer to the top-of-stack. The other possibility is that the offset is much smaller on x86, and is just 0xe68 (with just one pte error, it's hard to tell how many significant bits there are - there's no pattern as in Eric's case). That said, neither 0x1e68 nor 0xe68 seems to be in the main vmlinux file. But I haven't checked modules yet. Linus -- 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/