From mboxrd@z Thu Jan 1 00:00:00 1970 From: Li Zefan Subject: [PATCH] cls_cgroup: Fix rcu lockdep warning Date: Thu, 02 Sep 2010 14:30:07 +0800 Message-ID: <4C7F446F.8040303@cn.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Herbert Xu , Dave Jones , netdev , LKML To: David Miller Return-path: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Calling task_subsys_state() without holding rcu_read_lock or cgroup_mutex can cause lockdep warning. Reported-by: Dave Jones Signed-off-by: Li Zefan --- include/net/cls_cgroup.h | 10 ++++++++-- 1 files changed, 8 insertions(+), 2 deletions(-) diff --git a/include/net/cls_cgroup.h b/include/net/cls_cgroup.h index dd1fdb8..a4dc5b0 100644 --- a/include/net/cls_cgroup.h +++ b/include/net/cls_cgroup.h @@ -27,11 +27,17 @@ struct cgroup_cls_state #ifdef CONFIG_NET_CLS_CGROUP static inline u32 task_cls_classid(struct task_struct *p) { + int classid; + if (in_interrupt()) return 0; - return container_of(task_subsys_state(p, net_cls_subsys_id), - struct cgroup_cls_state, css)->classid; + rcu_read_lock(); + classid = container_of(task_subsys_state(p, net_cls_subsys_id), + struct cgroup_cls_state, css)->classid; + rcu_read_unlock(); + + return classid; } #else extern int net_cls_subsys_id; -- 1.6.3