Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754658AbYGROtU (ORCPT ); Fri, 18 Jul 2008 10:49:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754496AbYGROtE (ORCPT ); Fri, 18 Jul 2008 10:49:04 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:38168 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753111AbYGROtC (ORCPT ); Fri, 18 Jul 2008 10:49:02 -0400 Message-ID: <4880AD35.6080506@linux-foundation.org> Date: Fri, 18 Jul 2008 09:48:21 -0500 From: Christoph Lameter User-Agent: Thunderbird 2.0.0.14 (Windows/20080421) MIME-Version: 1.0 To: Pekka Enberg CC: Evgeniy Polyakov , Ingo Molnar , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, Vegard Nossum , "Rafael J. Wysocki" Subject: Re: [bug, netconsole, SLUB] BUG skbuff_head_cache: Poison overwritten References: <20080717214222.GA29449@elte.hu> <20080718054626.GA3338@2ka.mipt.ru> <84144f020807180202l6c703234ic3a2b57e73a1d89a@mail.gmail.com> <20080718101624.GA7107@2ka.mipt.ru> <84144f020807180744w40677f6dm790d2caee3ca0d15@mail.gmail.com> In-Reply-To: <84144f020807180744w40677f6dm790d2caee3ca0d15@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 751 Lines: 17 Pekka Enberg wrote: > Yeah. See the free_debug_processing() function in mm/slub.c for > details (the on_freelist() part). However, if you look at slab_free() > you can see that in the SLUB fast-path we don't do any of these > debugging checks. So you can end up with slab corruption without a > nice error message. The slub fastpath is not used when debugging is enabled. Without debugging on double frees will typically corrupt the freepointer. So you get an invalid pointer reference in __slab_free. -- 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/