From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757222AbZCMADT (ORCPT ); Thu, 12 Mar 2009 20:03:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751407AbZCMADL (ORCPT ); Thu, 12 Mar 2009 20:03:11 -0400 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:55647 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751272AbZCMADK (ORCPT ); Thu, 12 Mar 2009 20:03:10 -0400 From: KOSAKI Motohiro To: LKML Subject: [PATCH for tip] tracing: Don't use tracing_record_cmdline() in workqueue tracer fix Cc: kosaki.motohiro@jp.fujitsu.com, Ingo Molnar , Steven Rostedt , Frederic Weisbecker Message-Id: <20090313090042.43CD.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.50 [ja] Date: Fri, 13 Mar 2009 09:03:04 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org commit c3ffc7a40b7e94b094efe1c8ab4e24370a782b65 "Don't use tracing_record_cmdline() in workqueue tracer" have a race window. find_task_by_vpid() require task_list_lock(). but the patch doesn't. fixing here. Signed-off-by: KOSAKI Motohiro --- kernel/trace/trace_workqueue.c | 20 ++++++++++++++------ 1 files changed, 14 insertions(+), 6 deletions(-) diff --git a/kernel/trace/trace_workqueue.c b/kernel/trace/trace_workqueue.c index fb5ccac..9ab035b 100644 --- a/kernel/trace/trace_workqueue.c +++ b/kernel/trace/trace_workqueue.c @@ -193,12 +193,20 @@ static int workqueue_stat_show(struct seq_file *s, void *p) struct cpu_workqueue_stats *cws = p; unsigned long flags; int cpu = cws->cpu; - struct task_struct *tsk = find_task_by_vpid(cws->pid); - - seq_printf(s, "%3d %6d %6u %s\n", cws->cpu, - atomic_read(&cws->inserted), - cws->executed, - tsk ? tsk->comm : "<...>"); + struct pid *pid; + struct task_struct *tsk; + + pid = find_get_pid(cws->pid); + if (pid) { + tsk = get_pid_task(pid, PIDTYPE_PID); + if (tsk) { + seq_printf(s, "%3d %6d %6u %s\n", cws->cpu, + atomic_read(&cws->inserted), cws->executed, + tsk->comm); + put_task_struct(tsk); + } + put_pid(pid); + } spin_lock_irqsave(&workqueue_cpu_stat(cpu)->lock, flags); if (&cws->list == workqueue_cpu_stat(cpu)->list.next) -- 1.6.0.6