From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752244AbWAEWna (ORCPT ); Thu, 5 Jan 2006 17:43:30 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752204AbWAEWna (ORCPT ); Thu, 5 Jan 2006 17:43:30 -0500 Received: from fmr21.intel.com ([143.183.121.13]:704 "EHLO scsfmr001.sc.intel.com") by vger.kernel.org with ESMTP id S1752150AbWAEWn3 (ORCPT ); Thu, 5 Jan 2006 17:43:29 -0500 Date: Thu, 5 Jan 2006 14:42:10 -0800 From: Ashok Raj To: Tony Luck Cc: Nathan Lynch , linux-kernel@vger.kernel.org, Ben Collins , Andrew Morton , ashok.raj@intel.com Subject: Re: [PATCH] fix workqueue oops during cpu offline Message-ID: <20060105144210.A14956@unix-os.sc.intel.com> References: <20060105045810.GE16729@localhost.localdomain> <12c511ca0601051345pee8d8wc735507d361fa65e@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: <12c511ca0601051345pee8d8wc735507d361fa65e@mail.gmail.com>; from tony.luck@intel.com on Thu, Jan 05, 2006 at 01:45:50PM -0800 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 05, 2006 at 01:45:50PM -0800, Tony Luck wrote: > On 1/4/06, Nathan Lynch wrote: > > This is where things go wrong -- any_online_cpu() now gets 1, not 0. > > In queue_work, the cpu_workqueue_struct at per_cpu_ptr(wq->cpu_wq, 1) is > > uninitialized. > > Same issue on ia64 when I tried to add Ashok' s patch to allow > removal of cpu0 (BSP in ia64-speak). Ashok told me that this fix > solves the problem for us too. > Is this safe to use in NUMA path as well? Not that memory hot-remove is there yet today, but if a NUMA node is being removed, i would assume the memory for that node goes with it. i.e assuming alloc_percpu() gets node local memory for each cpu. So is it safe to continue to reference an area of an offline cpu that may not exist? -- Cheers, Ashok Raj - Open Source Technology Center