From: Linus Torvalds Subject: Re: 2.6.25-git2: BUG: unable to handle kernel paging request at ffffffffffffffff Date: Thu, 24 Apr 2008 18:48:32 -0700 (PDT) Message-ID: References: <4811090A.9030809@gmail.com> <20080424.183558.96469288.davem@davemloft.net> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: jirislaby@gmail.com, zdenek.kabelac@gmail.com, mingo@elte.hu, rjw@sisk.pl, paulmck@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, linux-ext4@vger.kernel.org, herbert@gondor.apana.org.au, penberg@cs.helsinki.fi, clameter@sgi.com To: David Miller Return-path: Received: from smtp1.linux-foundation.org ([140.211.169.13]:36315 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754256AbYDYBvS (ORCPT ); Thu, 24 Apr 2008 21:51:18 -0400 In-Reply-To: <20080424.183558.96469288.davem@davemloft.net> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Thu, 24 Apr 2008, David Miller wrote: > > So the clue is setting some byte at ((offset % 8) == 0) into a > structure with 0xf0... It's not always at (offset % 8) == 0. We've seen that 0xf0 pattern in other oopses, but it's not always 8-byte aligned. In fact, when we've seen it in oopses, it has generally been in the higher bytes (eg offset 5 within a 64-bit word, causing an invalid pointer on x86-64). But that 0xf0 definitely has shown up before. It's not the *only* corruption, but it's definitely a very interesting pattern. And the other ones that didn't show the 0xf0 pattern could obviously be due to pointers that were corrupted by 0xf0 in low bytes, so it _may_ be the source of the other corruptions too that didn't have an obvious 0xf0 directly in them. Linus