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Date: Tue, 31 May 2011 11:32:02 +0200
From: Stanislaw Gruszka <sgruszka@redhat.com>
To: Ivo Van Doorn <ivdoorn@gmail.com>
Cc: Stanislaw Gruszka <stf_xl@wp.pl>,
	Gertjan van Wingerde <gwingerde@gmail.com>,
	Helmut Schaa <helmut.schaa@googlemail.com>,
	linux-wireless@vger.kernel.org
Subject: Re: [PATCH wireless-2.6] rt2x00: fix rmmod crash
Message-ID: <20110531093201.GA15266@redhat.com> (sfid-20110531_113235_918522_09C586DF)
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Hello

On Mon, May 30, 2011 at 08:25:37PM +0200, Ivo Van Doorn wrote:
> On Sun, May 29, 2011 at 12:45 PM, Stanislaw Gruszka <stf_xl@wp.pl> wrote:
> > Do not destroy workqueue, which still can be used by autowakeup_work,
> > before ieee80211_unregister_hw() is called.
> 
> Well isn't the bug then that autowakeup_work isn't cancelled using
> cancel_work_sync
> like the other workqueue tasks?
> 
> I rather add the call to cancel_work_sync then moving the killing of
> the workqueue.
> The position where the workqueue is destroyed should be the place
> where we cancel
> all scheduled work, that way we can assume no rt2x00-related threads ater this
> position.

rt2x00lib_config() could be running simultaneously to rt2x00lib_remove_dev()
and queue just canceled autowake_work again into (just destroyed) workqueue.
Other solution to fix, would be use ieee80211_queue_work() instead of custom
workqueue, is that better?

Stanislaw