Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753749Ab0DVJ2y (ORCPT ); Thu, 22 Apr 2010 05:28:54 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:64032 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1753706Ab0DVJ2w (ORCPT ); Thu, 22 Apr 2010 05:28:52 -0400 Message-ID: <4BD01740.7050805@cn.fujitsu.com> Date: Thu, 22 Apr 2010 17:30:40 +0800 From: Li Zefan User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1b3pre) Gecko/20090513 Fedora/3.0-2.3.beta2.fc11 Thunderbird/3.0b2 MIME-Version: 1.0 To: LKML CC: "containers@lists.osdl.org" , "Paul E. McKenney" , Paul Menage , Andrew Morton , Ingo Molnar , Peter Zijlstra Subject: [PATCH 3/5] sched: Fix an RCU warning in print_task() References: <4BD016F4.8060108@cn.fujitsu.com> In-Reply-To: <4BD016F4.8060108@cn.fujitsu.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1056 Lines: 38 With CONFIG_PROVE_RCU=y, a warning can be triggered: $ cat /proc/sched_debug ... kernel/cgroup.c:1649 invoked rcu_dereference_check() without protection! ... Both cgroup_path() and task_group() should be called with either rcu_read_lock or cgroup_mutex held. Signed-off-by: Li Zefan --- kernel/sched_debug.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c index 9cf1baf..87a330a 100644 --- a/kernel/sched_debug.c +++ b/kernel/sched_debug.c @@ -114,7 +114,9 @@ print_task(struct seq_file *m, struct rq *rq, struct task_struct *p) { char path[64]; + rcu_read_lock(); cgroup_path(task_group(p)->css.cgroup, path, sizeof(path)); + rcu_read_unlock(); SEQ_printf(m, " %s", path); } #endif -- 1.6.3 -- 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/