Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932327AbWBQJJW (ORCPT ); Fri, 17 Feb 2006 04:09:22 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932354AbWBQJJW (ORCPT ); Fri, 17 Feb 2006 04:09:22 -0500 Received: from fw5.argo.co.il ([194.90.79.130]:3346 "EHLO argo2k.argo.co.il") by vger.kernel.org with ESMTP id S932327AbWBQJJV (ORCPT ); Fri, 17 Feb 2006 04:09:21 -0500 Message-ID: <43F592BC.9080606@argo.co.il> Date: Fri, 17 Feb 2006 11:09:16 +0200 From: Avi Kivity User-Agent: Mozilla Thunderbird 1.0.7-1.1.fc4 (X11/20050929) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Daniel Walker CC: Ingo Molnar , Johannes Stezenbach , linux-kernel@vger.kernel.org, Ulrich Drepper , Thomas Gleixner , Arjan van de Ven , David Singleton , Andrew Morton Subject: Re: [patch 0/5] lightweight robust futexes: -V1 References: <20060215151711.GA31569@elte.hu> <20060216145823.GA25759@linuxtv.org> <20060216172007.GB29151@elte.hu> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 17 Feb 2006 09:09:19.0687 (UTC) FILETIME=[D5D49D70:01C633A1] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1284 Lines: 33 Daniel Walker wrote: > On Thu, 16 Feb 2006, Ingo Molnar wrote: > >> >> that's memory corruption - which robust futexes do not (and cannot) >> solve. Robustness is mostly about handling sudden death (e.g. which is >> due to oom, or is due to a user killing the task, or due to the >> application crashing in some non-memory-corrupting way), but it cannot >> handle all possible failure modes. > > > I don't think this is a weakness in Dave or Inaky's versions. Dave > at least maintained the bulk of the information in kernel space. The > uaddr was used for the fast locking in userspace, but not for > maintaining the robustness . > > Correct me if I'm wrong Dave. In the general case of memory corruption, the data protected by the robust futex might be corrupted, and no robust futex implementation can protect against that, In fact it's a lot more likely since the application code has pointers to the data but not to the robust list. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic. - 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/