From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762856AbXJPCdS (ORCPT ); Mon, 15 Oct 2007 22:33:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757667AbXJPCdJ (ORCPT ); Mon, 15 Oct 2007 22:33:09 -0400 Received: from netops-testserver-3-out.sgi.com ([192.48.171.28]:51426 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1757555AbXJPCdI (ORCPT ); Mon, 15 Oct 2007 22:33:08 -0400 Date: Mon, 15 Oct 2007 19:32:59 -0700 From: Paul Jackson To: David Rientjes Cc: menage@google.com, nickpiggin@yahoo.com.au, a.p.zijlstra@chello.nl, balbir@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, clg@fr.ibm.com, ebiederm@xmission.com, containers@lists.osdl.org, serue@us.ibm.com, svaidy@linux.vnet.ibm.com, akpm@linux-foundation.org, xemul@openvz.org Subject: Re: [RFC] cpuset update_cgroup_cpus_allowed Message-Id: <20071015193259.f9eb51b2.pj@sgi.com> In-Reply-To: References: <20071015071115.16057.72116.sendpatchset@jackhammer.engr.sgi.com> Organization: SGI X-Mailer: Sylpheed version 2.2.4 (GTK+ 2.8.3; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > Yet by not doing any locking here to prevent a cpu from being > hot-unplugged, you can race and allow the hot-unplug event to happen > before calling set_cpus_allowed(). That makes this entire function a > no-op with set_cpus_allowed() returning -EINVAL for every call, which > isn't caught, and no error is reported to userspace. Good point ... hmmm ... -- I won't rest till it's the best ... Programmer, Linux Scalability Paul Jackson 1.925.600.0401