From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Miles Lane <miles.lane@gmail.com>
Cc: Vivek Goyal <vgoyal@redhat.com>, Eric Paris <eparis@redhat.com>,
Lai Jiangshan <laijs@cn.fujitsu.com>, Ingo Molnar <mingo@elte.hu>,
Peter Zijlstra <peterz@infradead.org>,
LKML <linux-kernel@vger.kernel.org>,
nauman@google.com, eric.dumazet@gmail.com,
netdev@vger.kernel.org, Jens Axboe <jens.axboe@oracle.com>,
Gui Jianfeng <guijianfeng@cn.fujitsu.com>,
Li Zefan <lizf@cn.fujitsu.com>,
Johannes Berg <johannes@sipsolutions.net>
Subject: Re: 2.6.35-rc2-git1 - include/linux/cgroup.h:534 invoked rcu_dereference_check() without protection!
Date: Mon, 7 Jun 2010 17:19:29 -0700 [thread overview]
Message-ID: <20100608001929.GF2387@linux.vnet.ibm.com> (raw)
In-Reply-To: <AANLkTin2pPqOUx--9fIX3BH3e-cU6oCRufijcx_4ozx5@mail.gmail.com>
On Mon, Jun 07, 2010 at 02:14:25PM -0400, Miles Lane wrote:
> Hi All,
>
> I just reproduced a warning I reported quite a while ago. Is a patch
> for this in the pipeline?
I proposed a patch, thinking that it was a false positive. Peter Zijlstra
pointed out that there was a real race, and proposed an alternative patch,
which may be found at http://lkml.org/lkml/2010/4/22/603.
Could you please test Peter's patch and let us know if it cures the problem?
Thanx, Paul
> [ 0.167267] [ INFO: suspicious rcu_dereference_check() usage. ]
> [ 0.167396] ---------------------------------------------------
> [ 0.167526] include/linux/cgroup.h:534 invoked
> rcu_dereference_check() without protection!
> [ 0.167728]
> [ 0.167729] other info that might help us debug this:
> [ 0.167731]
> [ 0.168092]
> [ 0.168093] rcu_scheduler_active = 1, debug_locks = 1
> [ 0.168337] no locks held by watchdog/0/5.
> [ 0.168462]
> [ 0.168463] stack backtrace:
> [ 0.168704] Pid: 5, comm: watchdog/0 Not tainted 2.6.35-rc2-git1 #8
> [ 0.168834] Call Trace:
> [ 0.168965] [<ffffffff81064e9c>] lockdep_rcu_dereference+0x9d/0xa5
> [ 0.169100] [<ffffffff8102c1ce>] task_subsys_state+0x59/0x70
> [ 0.169232] [<ffffffff8103189b>] __sched_setscheduler+0x19d/0x2f8
> [ 0.169365] [<ffffffff8102a5ef>] ? need_resched+0x1e/0x28
> [ 0.169497] [<ffffffff813c7d01>] ? schedule+0x586/0x619
> [ 0.169628] [<ffffffff81081c33>] ? watchdog+0x0/0x8c
> [ 0.169758] [<ffffffff81031a11>] sched_setscheduler+0xe/0x10
> [ 0.169889] [<ffffffff81081c5d>] watchdog+0x2a/0x8c
> [ 0.170010] [<ffffffff81081c33>] ? watchdog+0x0/0x8c
> [ 0.170141] [<ffffffff81054a82>] kthread+0x89/0x91
> [ 0.170274] [<ffffffff81003054>] kernel_thread_helper+0x4/0x10
> [ 0.170405] [<ffffffff813ca480>] ? restore_args+0x0/0x30
> [ 0.170536] [<ffffffff810549f9>] ? kthread+0x0/0x91
> [ 0.170667] [<ffffffff81003050>] ? kernel_thread_helper+0x0/0x10
> [ 0.176751] lockdep: fixing up alternatives.
next prev parent reply other threads:[~2010-06-08 0:19 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-07 18:14 2.6.35-rc2-git1 - include/linux/cgroup.h:534 invoked rcu_dereference_check() without protection! Miles Lane
2010-06-08 0:19 ` Paul E. McKenney [this message]
2010-06-08 4:16 ` Miles Lane
2010-06-08 8:40 ` Peter Zijlstra
2010-06-08 13:14 ` Miles Lane
2010-06-08 13:34 ` Peter Zijlstra
2010-06-09 15:11 ` Miles Lane
2010-06-09 15:24 ` Peter Zijlstra
2010-06-09 15:29 ` Miles Lane
2010-06-09 17:00 ` Miles Lane
2010-06-09 17:57 ` Peter Zijlstra
2010-06-09 18:15 ` Peter Zijlstra
2010-06-09 21:15 ` Miles Lane
2010-06-09 21:20 ` Peter Zijlstra
[not found] ` <AANLkTilsDv59zbL7rbAgJByz_vSnZ0QlbK3dVJUX2VYQ@mail.gmail.com>
2010-06-22 9:44 ` [PATCH] sched: silence PROVE_RCU in sched_fork() Peter Zijlstra
2010-06-23 7:25 ` Li Zefan
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