From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753398AbXDUM7k (ORCPT ); Sat, 21 Apr 2007 08:59:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751024AbXDUM7k (ORCPT ); Sat, 21 Apr 2007 08:59:40 -0400 Received: from ausmtp05.au.ibm.com ([202.81.18.154]:39020 "EHLO ausmtp05.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753349AbXDUM7i (ORCPT ); Sat, 21 Apr 2007 08:59:38 -0400 Message-ID: <462A0AA9.8000304@linux.vnet.ibm.com> Date: Sat, 21 Apr 2007 18:29:21 +0530 From: Balbir Singh Reply-To: balbir@linux.vnet.ibm.com Organization: IBM User-Agent: Thunderbird 1.5.0.10 (X11/20070306) MIME-Version: 1.0 To: Andrew Morton CC: Balbir Singh , nagar@watson.ibm.com, jlan@sgi.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH -mm] Taskstats fix the structure members alignment issue References: <20070420164341.14718.5013.sendpatchset@balbir-laptop> <20070420121543.6a1a8426.akpm@linux-foundation.org> In-Reply-To: <20070420121543.6a1a8426.akpm@linux-foundation.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andrew Morton wrote: > On Fri, 20 Apr 2007 22:13:41 +0530 > Balbir Singh wrote: > >> We broke the the alignment of members of taskstats to the 8 byte boundary >> with the CSA patches. In the current kernel, the taskstats structure is >> not suitable for use by 32 bit applications in a 64 bit kernel. >> > > ugh, that was bad of us. Yes :-) > >> ... >> The patch adds an __attribute__((aligned(8))) to the >> taskstats structure members so that 32 bit applications using taskstats >> can work with a 64 bit kernel. > > But there might be 32-bit applications out there which are using the > present wrong structure? > > otoh, I assume that those applications would be using taskstats.h and would > hence encounter this bug and we would have heard about it, is that correct? > Yes, correct. > otoh^2, 32-bit applications running under 32-bit kernels will presently be > functioning correctly, and your change will require that those applications > be recompiled, I think? > Yes, correct. They would be broken with this fix. We could bump up the version TASKSTATS_VERSION to 4. Would you like a new patch the version bumped up? > > This patch looks like 2.6.20 and 2.6.21 material, but very carefully... Yes, 2.6.20 and 2.6.21 sound correct. -- Warm Regards, Balbir Singh Linux Technology Center IBM, ISTL