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Subject: Re: [3.0-rc4] lockdep: netdev notifier vs rfkill
From: Luciano Coelho <coelho@ti.com>
To: Daniel J Blueman <daniel.blueman@gmail.com>
Cc: Johannes Berg <johannes@sipsolutions.net>,
	"John W. Linville" <linville@tuxdriver.com>,
	linux-wireless@vger.kernel.org
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Date: Thu, 30 Jun 2011 08:34:17 +0300
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On Tue, 2011-06-21 at 21:10 +0800, Daniel J Blueman wrote: 
> When hitting the hard rfkill in 3.0-rc4, lockdep spots some likely lock misuse:
> 
> =======================================================
> [ INFO: possible circular locking dependency detected ]
> 3.0.0-rc4-340c #1
> -------------------------------------------------------
> kworker/0:0/4 is trying to acquire lock:
>  (&rdev->mtx){+.+.+.}, at: [<ffffffff816cefce>]
> cfg80211_netdev_notifier_call+0x11e/0x650
> 
> but task is already holding lock:
>  (&rdev->devlist_mtx){+.+.+.}, at: [<ffffffff816cff16>]
> cfg80211_rfkill_set_block+0x46/0xa0
> 
> which lock already depends on the new lock.

This should be fixed with the patch for 3.0 that I have just sent,
"cfg80211: fix deadlock with rfkill/sched_scan by adding new mutex".

-- 
Cheers,
Luca.