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Date: Tue, 10 Mar 2009 11:10:20 +0200
From: Jouni Malinen <j@w1.fi>
To: "Luis R. Rodriguez" <lrodriguez@atheros.com>
Cc: linux-wireless@vger.kernel.org
Subject: Re: [RFC] cfg80211: send regulatory beacon hint events to userspace
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On Mon, Mar 09, 2009 at 10:48:52PM -0400, Luis R. Rodriguez wrote:

> There is something awefully wrong with this patch and after some
> good review I cannot determine what is wrong with it. The issue is
> I end up following bug complaint saying I'm sleeping while I'm atomic..
> but this is all from a workqueue so what gives?

You hold a spinlock while trying to alloc memory with GFP_KERNEL..

> [14462.644641]  [<ffffffff804a40c4>] __alloc_skb+0x44/0x140
> [14462.644652]  [<ffffffffa051a8b3>] nl80211_send_beacon_hint_event+0x33/0x370 [cfg80211]
> [14462.644660]  [<ffffffff8026960e>] ? put_lock_stats+0xe/0x30
> [14462.644671]  [<ffffffffa0511f19>] handle_reg_beacon+0xa9/0xc0 [cfg80211]
> [14462.644685]  [<ffffffffa0512500>] ? reg_todo+0x0/0x5c0 [cfg80211]
> [14462.644696]  [<ffffffff80541a1d>] ? _spin_lock_bh+0x6d/0x80

That would be spin_lock_bh() from reg_process_pending_beacon_hints(), I
would assume.. nl80211_send_beacon_hint_event() cannot use GFP_KERNEL on
such a call path.

-- 
Jouni Malinen                                            PGP id EFC895FA