From: Li Zefan <lizf@cn.fujitsu.com>
To: David Miller <davem@davemloft.net>
Cc: Herbert Xu <herbert@gondor.hengli.com.au>,
Dave Jones <davej@redhat.com>, netdev <netdev@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: [PATCH] cls_cgroup: Fix rcu lockdep warning
Date: Thu, 02 Sep 2010 14:30:07 +0800 [thread overview]
Message-ID: <4C7F446F.8040303@cn.fujitsu.com> (raw)
Calling task_subsys_state() without holding rcu_read_lock or
cgroup_mutex can cause lockdep warning.
Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
---
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
next reply other threads:[~2010-09-02 6:25 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-02 6:30 Li Zefan [this message]
2010-09-02 10:38 ` [PATCH] cls_cgroup: Fix rcu lockdep warning Peter Zijlstra
2010-09-02 17:05 ` David Miller
2010-09-02 17:16 ` Paul E. McKenney
2010-09-03 1:10 ` Li Zefan
2010-09-03 4:52 ` Herbert Xu
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