From: Sitsofe Wheeler <sitsofe@yahoo.com>
To: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org
Subject: lockdep recursive locking detected (rcu_kthread / __cache_free)
Date: Mon, 3 Oct 2011 18:53:22 +0100 [thread overview]
Message-ID: <20111003175322.GA26122@sucs.org> (raw)
Hi,
While running 3.1.0-rc8 the following lockdep warning (seemingly related
to RCU) was printed as the kernel was starting.
udev: starting version 151
udevd (263): /proc/263/oom_adj is deprecated, please use /proc/263/oom_score_adj instead.
=============================================
[ INFO: possible recursive locking detected ]
3.1.0-rc8-dirty #508
---------------------------------------------
rcu_kthread/6 is trying to acquire lock:
(&(&parent->list_lock)->rlock){..-...}, at: [<b016fe11>] __cache_free+0x2dd/0x382
but task is already holding lock:
(&(&parent->list_lock)->rlock){..-...}, at: [<b016fe11>] __cache_free+0x2dd/0x382
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&(&parent->list_lock)->rlock);
lock(&(&parent->list_lock)->rlock);
*** DEADLOCK ***
May be due to missing lock nesting notation
1 lock held by rcu_kthread/6:
#0: (&(&parent->list_lock)->rlock){..-...}, at: [<b016fe11>] __cache_free+0x2dd/0x382
stack backtrace:
Pid: 6, comm: rcu_kthread Not tainted 3.1.0-rc8-dirty #508
Call Trace:
[<b0144466>] __lock_acquire+0xb90/0xc0e
[<b044c0c2>] ? _raw_spin_unlock_irqrestore+0x2f/0x46
[<b0223ebc>] ? debug_object_active_state+0x94/0xbc
[<b01315af>] ? rcuhead_fixup_activate+0x26/0x4c
[<b01448be>] lock_acquire+0x5b/0x72
[<b016fe11>] ? __cache_free+0x2dd/0x382
[<b044bb22>] _raw_spin_lock+0x25/0x34
[<b016fe11>] ? __cache_free+0x2dd/0x382
[<b016fe11>] __cache_free+0x2dd/0x382
[<b016ff5c>] kmem_cache_free+0x3e/0x5b
[<b0170097>] slab_destroy+0x11e/0x126
[<b0170184>] free_block+0xe5/0x112
[<b016fe54>] __cache_free+0x320/0x382
[<b01759a1>] ? file_free_rcu+0x32/0x39
[<b016ff5c>] kmem_cache_free+0x3e/0x5b
[<b01759a1>] file_free_rcu+0x32/0x39
[<b014ca68>] rcu_process_callbacks+0x95/0xa8
[<b014cb34>] rcu_kthread+0xb9/0xd2
[<b013356c>] ? wake_up_bit+0x1b/0x1b
[<b014ca7b>] ? rcu_process_callbacks+0xa8/0xa8
[<b0133305>] kthread+0x6c/0x71
[<b0133299>] ? __init_kthread_worker+0x42/0x42
[<b044ce02>] kernel_thread_helper+0x6/0xd
--
Sitsofe | http://sucs.org/~sits/
next reply other threads:[~2011-10-03 17:53 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-03 17:53 Sitsofe Wheeler [this message]
2011-10-03 20:31 ` lockdep recursive locking detected (rcu_kthread / __cache_free) Paul E. McKenney
2011-10-03 20:46 ` Christoph Lameter
2011-10-03 21:06 ` Peter Zijlstra
2011-10-03 21:47 ` Paul E. McKenney
2011-10-04 14:28 ` Christoph Lameter
2011-10-04 14:40 ` Peter Zijlstra
2011-10-04 14:50 ` Christoph Lameter
2011-10-04 15:09 ` Peter Zijlstra
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