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From: Peter Zijlstra <peterz@infradead.org>
To: Fengguang Wu <fengguang.wu@intel.com>
Cc: "Nicolai Hähnle" <Nicolai.Haehnle@amd.com>,
	"Chris Wilson" <chris@chris-wilson.co.uk>,
	"Ingo Molnar" <mingo@kernel.org>,
	linux-kernel@vger.kernel.org, LKP <lkp@01.org>
Subject: Re: [locking/ww_mutex] 2a0c112828 WARNING: CPU: 0 PID: 18 at kernel/locking/mutex.c:305 __ww_mutex_wakeup_for_backoff
Date: Mon, 27 Feb 2017 11:35:43 +0100	[thread overview]
Message-ID: <20170227103543.GA6536@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20170227102824.GV6500@twins.programming.kicks-ass.net>

On Mon, Feb 27, 2017 at 11:28:24AM +0100, Peter Zijlstra wrote:
> On Mon, Feb 27, 2017 at 01:14:09PM +0800, Fengguang Wu wrote:
> > Hello,
> > 
> > This bisect result is not satisfactory, however the bug is very
> > reproducible and looks still alive in mainline&linux-next. You may
> > try the attached reproduce-* script to debug it.
> 
> OK, let me try that, however, see below.

What that reproduces does is:


[   17.169056] =====================================
[   17.171014] [ BUG: bad unlock balance detected! ]
[   17.172115] 4.10.0-10265-ge5d56ef #18 Not tainted
[   17.172115] -------------------------------------
[   17.172115] kworker/u2:0/5 is trying to release lock (ww_class_mutex) at:
[   17.172115] [<41575474>] ww_mutex_unlock+0x66/0x72
[   17.172115] but there are no more locks to release!
[   17.172115] 
[   17.172115] other info that might help us debug this:
[   17.172115] 
[   17.172115] other info that might help us debug this:
[   17.172115] 4 locks held by kworker/u2:0/5:
[   17.172115]  #0:  ("test-ww_mutex"){......}, at: [<41041def>] process_one_work+0x168/0x33a
[   17.172115]  #1:  ((&stress->work)){......}, at: [<41041def>] process_one_work+0x168/0x33a
[   17.172115]  #2:  (ww_class_acquire){......}, at: [<41041e47>] process_one_work+0x1c0/0x33a
[   17.172115]  #3:  (ww_class_mutex){......}, at: [<41057d98>] stress_inorder_work+0xbf/0x218
[   17.172115] 
[   17.172115] stack backtrace:
[   17.172115] 
[   17.172115] stack backtrace:
[   17.172115] CPU: 0 PID: 5 Comm: kworker/u2:0 Not tainted 4.10.0-10265-ge5d56ef #18
[   17.172115] Workqueue: test-ww_mutex stress_inorder_work
[   17.172115] Call Trace:
[   17.172115]  dump_stack+0x16/0x18
[   17.172115]  print_unlock_imbalance_bug+0xb4/0xc1
[   17.172115]  ? ww_mutex_unlock+0x66/0x72
[   17.172115]  lock_release+0x28d/0x2bb
[   17.172115]  ? ww_mutex_unlock+0x66/0x72
[   17.172115]  __mutex_unlock_slowpath+0x2d/0x1db
[   17.172115]  ? schedule_hrtimeout_range+0xd/0xf
[   17.172115]  mutex_unlock+0xb/0xd
[   17.172115]  ww_mutex_unlock+0x66/0x72
[   17.172115]  stress_inorder_work+0x10a/0x218
[   17.172115]  process_one_work+0x1c0/0x33a
[   17.172115]  ? process_one_work+0x168/0x33a
[   17.172115]  worker_thread+0x22f/0x315
[   17.172115]  kthread+0xed/0xf2
[   17.172115]  ? process_scheduled_works+0x24/0x24
[   17.172115]  ? __kthread_create_on_node+0x11f/0x11f
[   17.172115]  ret_from_fork+0x21/0x30

Which is an entirely different error.. Lemme look into that.

  reply	other threads:[~2017-02-27 11:44 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-27  5:14 Fengguang Wu
2017-02-27 10:28 ` Peter Zijlstra
2017-02-27 10:35   ` Peter Zijlstra [this message]
2017-03-01 15:01     ` Boqun Feng
2017-03-01 15:18       ` Peter Zijlstra
     [not found]       ` <20170301154043.hcsbpgooc3kqt45j@wfg-t540p.sh.intel.com>
2017-03-01 15:51         ` Peter Zijlstra
2017-03-01 15:55           ` Fengguang Wu
2017-03-01 15:54         ` Peter Zijlstra
2017-03-01 16:11           ` Chris Wilson
2017-03-01 16:26             ` Chris Wilson
2017-03-01 16:54               ` Peter Zijlstra
2017-03-01 17:39                 ` Fengguang Wu
2017-03-02  8:21       ` [tip:locking/urgent] locking/ww_mutex: Adjust the lock number for stress test tip-bot for Boqun Feng

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