Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932551Ab3CTSKZ (ORCPT ); Wed, 20 Mar 2013 14:10:25 -0400 Received: from mail-pb0-f42.google.com ([209.85.160.42]:54772 "EHLO mail-pb0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756571Ab3CTSKY (ORCPT ); Wed, 20 Mar 2013 14:10:24 -0400 Date: Wed, 20 Mar 2013 11:10:10 -0700 From: Tejun Heo To: Lai Jiangshan Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH 15/21] workqueue: remove worker_maybe_bind_and_lock() Message-ID: <20130320181010.GA30484@htj.dyndns.org> References: <1363721306-2030-1-git-send-email-laijs@cn.fujitsu.com> <1363721306-2030-16-git-send-email-laijs@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1363721306-2030-16-git-send-email-laijs@cn.fujitsu.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 888 Lines: 26 On Wed, Mar 20, 2013 at 03:28:15AM +0800, Lai Jiangshan wrote: > static struct worker *alloc_worker(void) > { > struct worker *worker; > @@ -2326,7 +2262,8 @@ repeat: > spin_unlock_irq(&wq_mayday_lock); > > /* migrate to the target cpu if possible */ > - worker_maybe_bind_and_lock(pool); > + set_cpus_allowed_ptr(current, pool->attrs->cpumask); > + spin_lock_irq(&pool->lock); > rescuer->pool = pool; You can't do this. The CPU might go up between set_cpus_allowed_ptr() and spin_lock_irq() and the rescuer can end up executing a work item which was issued while the target CPU is up on the wrong CPU. Thanks. -- tejun -- 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/