From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754028Ab2DWHJr (ORCPT ); Mon, 23 Apr 2012 03:09:47 -0400 Received: from mail-ob0-f174.google.com ([209.85.214.174]:45494 "EHLO mail-ob0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750945Ab2DWHJo (ORCPT ); Mon, 23 Apr 2012 03:09:44 -0400 Date: Mon, 23 Apr 2012 00:08:28 -0700 From: Anton Vorontsov To: Andrew Morton , Oleg Nesterov Cc: Russell King , Mike Frysinger , Benjamin Herrenschmidt , Richard Weinberger , Paul Mundt , Peter Zijlstra , KOSAKI Motohiro , John Stultz , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, uclinux-dist-devel@blackfin.uclinux.org, linuxppc-dev@lists.ozlabs.org, linux-sh@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net, linaro-kernel@lists.linaro.org, patches@linaro.org, linux-mm@kvack.org Subject: [PATCH 2/9] arm: Use clear_tasks_mm_cpumask() Message-ID: <20120423070828.GB30752@lizard> References: <20120423070641.GA27702@lizard> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20120423070641.GA27702@lizard> 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 Checking for process->mm is not enough because process' main thread may exit or detach its mm via use_mm(), but other threads may still have a valid mm. To fix this we would need to use find_lock_task_mm(), which would walk up all threads and returns an appropriate task (with task lock held). clear_tasks_mm_cpumask() has this issue fixed, so let's use it. Suggested-by: Oleg Nesterov Signed-off-by: Anton Vorontsov --- arch/arm/kernel/smp.c | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index addbbe8..e824ee4 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -130,7 +130,6 @@ static void percpu_timer_stop(void); int __cpu_disable(void) { unsigned int cpu = smp_processor_id(); - struct task_struct *p; int ret; ret = platform_cpu_disable(cpu); @@ -160,12 +159,7 @@ int __cpu_disable(void) flush_cache_all(); local_flush_tlb_all(); - read_lock(&tasklist_lock); - for_each_process(p) { - if (p->mm) - cpumask_clear_cpu(cpu, mm_cpumask(p->mm)); - } - read_unlock(&tasklist_lock); + clear_tasks_mm_cpumask(cpu); return 0; } -- 1.7.9.2