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Subject: Re: net/bluetooth: workqueue destruction WARNING in
 hci_unregister_dev
To: Tejun Heo <tj@kernel.org>
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Cc: Dmitry Vyukov <dvyukov@google.com>, Marcel Holtmann <marcel@holtmann.org>,
        Gustavo Padovan <gustavo@padovan.org>,
        Johan Hedberg <johan.hedberg@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
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        Eric Dumazet <edumazet@google.com>, Takashi Iwai <tiwai@suse.com>
From: Jiri Slaby <jslaby@suse.cz>
Message-ID: <56D7FFE1.90900@suse.cz>
Date: Thu, 3 Mar 2016 10:12:01 +0100
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Hi,

On 03/02/2016, 04:45 PM, Tejun Heo wrote:
> On Fri, Feb 19, 2016 at 01:10:00PM +0100, Jiri Slaby wrote:
>>> 1. didn't help, the problem persists. So I haven't applied the patch from 2.
>>
>> FWIW I dumped more info about the wq:
>> wq->name='hci0' pwq=ffff8800390d7600 wq->dfl_pwq=ffff8800390d5200
>> pwq->refcnt=2 pwq->nr_active=0 delayed_works: <nothing>
> 
> Can you please print out the same info for all pwq's during shutdown?
> It looks like we're leaking pwq refcnt but I can't spot a place where
> that could happen on an empty pwq.

I have not done that yet, but today, I see:
destroy_workqueue: name='req_hci0' pwq=ffff88002f590300
wq->dfl_pwq=ffff88002f591e00 pwq->refcnt=2 pwq->nr_active=0 delayed_works:
   pwq 12: cpus=0-1 node=0 flags=0x4 nice=-20 active=0/1
     in-flight: 18568:wq_barrier_func

thanks,
-- 
js
suse labs