From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755314Ab0JESCJ (ORCPT ); Tue, 5 Oct 2010 14:02:09 -0400 Received: from mail.candelatech.com ([208.74.158.172]:53837 "EHLO ns3.lanforge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753133Ab0JESCI (ORCPT ); Tue, 5 Oct 2010 14:02:08 -0400 X-Greylist: delayed 1908 seconds by postgrey-1.27 at vger.kernel.org; Tue, 05 Oct 2010 14:02:08 EDT Message-ID: <4CAB60AB.5060808@candelatech.com> Date: Tue, 05 Oct 2010 10:30:19 -0700 From: Ben Greear Organization: Candela Technologies User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100430 Fedora/3.0.4-2.fc11 Thunderbird/3.0.4 MIME-Version: 1.0 To: linux-kernel Subject: Can SLUB debugging show back-trace for deletion point? Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org I'm debugging a wireless issue that is apparently a write-after-free issue with skbs. Oct 5 09:50:18 localhost kernel: ============================================================================= Oct 5 09:50:18 localhost kernel: BUG kmalloc-8192: Poison overwritten Oct 5 09:50:18 localhost kernel: ----------------------------------------------------------------------------- Oct 5 09:50:18 localhost kernel: Oct 5 09:50:18 localhost kernel: INFO: 0xf5b18040-0xf5b1812f. First byte 0x80 instead of 0x6b Oct 5 09:50:18 localhost kernel: INFO: Allocated in ath_rxbuf_alloc+0x1d/0x74 [ath] age=54091 cpu=0 pid=613 Oct 5 09:50:18 localhost kernel: INFO: Freed in skb_release_data+0x8c/0x90 age=89 cpu=0 pid=4029 Oct 5 09:50:18 localhost kernel: INFO: Slab 0xc1fef300 objects=3 used=2 fp=0xf5b18000 flags=0x400040c1 Oct 5 09:50:18 localhost kernel: INFO: Object 0xf5b18000 @offset=0 fp=0x(null) .... I get a backtrace for the point at which this is detected, but it seems what would really be useful is a backtrace for where it was freed. Is there any way to get that information printed out by slub debugging? Thanks, Ben -- Ben Greear Candela Technologies Inc http://www.candelatech.com