From: Peter Zijlstra <peterz@infradead.org>
To: Li Zefan <lizf@cn.fujitsu.com>
Cc: David Miller <davem@davemloft.net>,
Herbert Xu <herbert@gondor.hengli.com.au>,
Dave Jones <davej@redhat.com>, netdev <netdev@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: Re: [PATCH] cls_cgroup: Fix rcu lockdep warning
Date: Thu, 02 Sep 2010 12:38:36 +0200 [thread overview]
Message-ID: <1283423916.2059.1847.camel@laptop> (raw)
In-Reply-To: <4C7F446F.8040303@cn.fujitsu.com>
On Thu, 2010-09-02 at 14:30 +0800, Li Zefan wrote:
> Calling task_subsys_state() without holding rcu_read_lock or
> cgroup_mutex can cause lockdep warning.
>
That is not a suitable changelog.
Was the warning correct? Is your patch correct? What does RCU protect
here and why can we use classid after dropping it.
Simply frobbing code to make the warning go away is not good.
next prev parent reply other threads:[~2010-09-02 10:38 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-02 6:30 [PATCH] cls_cgroup: Fix rcu lockdep warning Li Zefan
2010-09-02 10:38 ` Peter Zijlstra [this message]
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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