From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932260AbXCHRpp (ORCPT ); Thu, 8 Mar 2007 12:45:45 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752612AbXCHRpp (ORCPT ); Thu, 8 Mar 2007 12:45:45 -0500 Received: from e6.ny.us.ibm.com ([32.97.182.146]:49210 "EHLO e6.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752609AbXCHRpo (ORCPT ); Thu, 8 Mar 2007 12:45:44 -0500 Date: Thu, 8 Mar 2007 23:22:33 +0530 From: Srivatsa Vaddagiri To: menage@google.com Cc: akpm@osdl.org, pj@sgi.com, sekharan@us.ibm.com, dev@sw.ru, xemul@sw.ru, serue@us.ibm.com, ebiederm@xmission.com, ckrm-tech@lists.sourceforge.net, linux-kernel@vger.kernel.org, rohitseth@google.com, mbligh@google.com, winget@google.com, containers@lists.osdl.org, devel@openvz.org Subject: Re: [PATCH 3/7] containers (V7): Add generic multi-subsystem API to containers Message-ID: <20070308175233.GK6504@in.ibm.com> Reply-To: vatsa@in.ibm.com References: <20070212081521.808338000@menage.corp.google.com> <20070212085104.485337000@menage.corp.google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070212085104.485337000@menage.corp.google.com> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 12, 2007 at 12:15:24AM -0800, menage@google.com wrote: > +static struct container_group *find_container_group( > + struct container_group *oldcg, struct container *cont) > +{ > + struct container_group *res; > + struct container_subsys *ss; > + int h = cont->hierarchy; > + int i; > + > + BUG_ON(oldcg->container[h] == cont); > + /* First see if we already have a container group that matches > + * the desired set */ > + spin_lock(&container_group_lock); I think this should be spin_lock_irq(). I have been bitten by lockdep warning in the rcfs patchs. But I think they should apply here as well. Essentially, container_task_count() is called from cpuset.c after doing write_lock_irq(tasklist_lock). This creates the dependency: tasklist_lock (irqs disabled) -> container_group_lock However in above function, find_container_group (and several other functions) we take container_group_lock w/o blocking interrupts. An interrupt handler now trying to take tasklist_lock will cause a deadlock. -- Regards, vatsa