From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1754047AbbGaRoF (ORCPT <rfc822;w@1wt.eu>);
	Fri, 31 Jul 2015 13:44:05 -0400
Received: from arcturus.aphlor.org ([188.246.204.175]:48256 "EHLO
	arcturus.aphlor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1753655AbbGaRoB (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Fri, 31 Jul 2015 13:44:01 -0400
Date: Fri, 31 Jul 2015 13:43:53 -0400
From: Dave Jones <davej@codemonkey.org.uk>
To: Linux Kernel <linux-kernel@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Subject: unpinning an unpinned lock. (pidns/scheduler)
Message-ID: <20150731174353.GA25799@codemonkey.org.uk>
Mail-Followup-To: Dave Jones <davej@codemonkey.org.uk>,
	Linux Kernel <linux-kernel@vger.kernel.org>,
	Peter Zijlstra <peterz@infradead.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
User-Agent: Mutt/1.5.23 (2014-03-12)
X-Spam-Score: -2.9 (--)
X-Spam-Report: Spam report generated by SpamAssassin on "arcturus.aphlor.org"
 Content analysis details:   (-2.9 points, 5.0 required)
  pts rule name              description
 ---- ---------------------- --------------------------------------------------
 -1.0 ALL_TRUSTED            Passed through trusted hosts only via SMTP
 -1.9 BAYES_00               BODY: Bayes spam probability is 0 to 1%
                             [score: 0.0000]
X-Authenticated-User: davej@codemonkey.org.uk
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

Just found a machine with this on 4.2-rc4

WARNING: CPU: 0 PID: 11787 at kernel/locking/lockdep.c:3497 lock_unpin_lock+0x109/0x110()
unpinning an unpinned lock
CPU: 0 PID: 11787 Comm: kworker/0:1 Not tainted 4.2.0-rc4-think+ #5
Workqueue: events proc_cleanup_work
 0000000000000009 ffff8804f8983988 ffffffff9f7f5eed 0000000000000007
 ffff8804f89839d8 ffff8804f89839c8 ffffffff9f07b72a 00000000000000a8
 0000000000000070 ffff8805079d5c98 0000000000000092 0000000000000002
Call Trace:
 [<ffffffff9f7f5eed>] dump_stack+0x4f/0x7b
 [<ffffffff9f07b72a>] warn_slowpath_common+0x8a/0xc0
 [<ffffffff9f07b7a6>] warn_slowpath_fmt+0x46/0x50
 [<ffffffff9f0d0c59>] lock_unpin_lock+0x109/0x110
 [<ffffffff9f7f944f>] __schedule+0x39f/0xb30
 [<ffffffff9f7f9ca1>] schedule+0x41/0x90
 [<ffffffff9f7fe88f>] schedule_timeout+0x33f/0x5b0
 [<ffffffff9f0cfdfe>] ? put_lock_stats.isra.29+0xe/0x30
 [<ffffffff9f0d33d5>] ? mark_held_locks+0x75/0xa0
 [<ffffffff9f7ffb70>] ? _raw_spin_unlock_irq+0x30/0x60
 [<ffffffff9f0ad5e1>] ? get_parent_ip+0x11/0x50
 [<ffffffff9f7fb16c>] wait_for_completion+0xec/0x120
 [<ffffffff9f0abfc0>] ? wake_up_q+0x70/0x70
 [<ffffffff9f0f38f0>] ? rcu_barrier+0x20/0x20
 [<ffffffff9f0ea3f8>] wait_rcu_gp+0x68/0x90
 [<ffffffff9f0ea370>] ? trace_raw_output_rcu_barrier+0x80/0x80
 [<ffffffff9f7fb0b8>] ? wait_for_completion+0x38/0x120
 [<ffffffff9f0ee4dc>] synchronize_rcu+0x3c/0xb0
 [<ffffffff9f21de3f>] kern_unmount+0x2f/0x40
 [<ffffffff9f26dca5>] pid_ns_release_proc+0x15/0x20
 [<ffffffff9f1354b5>] proc_cleanup_work+0x15/0x20
 [<ffffffff9f0993f3>] process_one_work+0x1f3/0x7a0
 [<ffffffff9f099362>] ? process_one_work+0x162/0x7a0
 [<ffffffff9f099a99>] ? worker_thread+0xf9/0x470
 [<ffffffff9f099a09>] worker_thread+0x69/0x470
 [<ffffffff9f0ad773>] ? preempt_count_sub+0xa3/0xf0
 [<ffffffff9f0999a0>] ? process_one_work+0x7a0/0x7a0
 [<ffffffff9f09fbbf>] kthread+0x11f/0x140
 [<ffffffff9f09faa0>] ? kthread_create_on_node+0x250/0x250
 [<ffffffff9f80098f>] ret_from_fork+0x3f/0x70
 [<ffffffff9f09faa0>] ? kthread_create_on_node+0x250/0x250
---[ end trace e75342db87128aeb ]---