From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753770Ab0C2VPa (ORCPT ); Mon, 29 Mar 2010 17:15:30 -0400 Received: from e4.ny.us.ibm.com ([32.97.182.144]:50279 "EHLO e4.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752822Ab0C2VP3 (ORCPT ); Mon, 29 Mar 2010 17:15:29 -0400 Date: Mon, 29 Mar 2010 14:15:25 -0700 From: "Paul E. McKenney" To: linux-kernel@vger.kernel.org Cc: mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca, josh@joshtriplett.org, dvhltc@us.ibm.com, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, Valdis.Kletnieks@vt.edu, dhowells@redhat.com, eric.dumazet@gmail.com, abogani@texware.it Subject: [PATCH tip/core/urgent] rcu: protect fork-time cgroup access Message-ID: <20100329211525.GA17703@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add an rcu_read_lock() / rcu_read_unlock() pair to protect a fork-time cgroup access. This seems likely to be a false positive. Located by: Alessio Igor Bogani Signed-off-by: Paul E. McKenney --- sched.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/sched.c b/kernel/sched.c index 9ab3cd7..d4bb5e0 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2621,7 +2621,9 @@ void sched_fork(struct task_struct *p, int clone_flags) if (p->sched_class->task_fork) p->sched_class->task_fork(p); + rcu_read_lock(); set_task_cpu(p, cpu); + rcu_read_unlock(); #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) if (likely(sched_info_on()))