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Commit 96869a39 authored by Michael Buesch's avatar Michael Buesch Committed by John W. Linville
Browse files

b43: Workaround circular locking in hw-tkip key update callback 



The TKIP key update callback is called from the RX path, where the driver
mutex is already locked. This results in a circular locking bug.
Avoid this by removing the lock.

Johannes noted that there is a separate bug: The callback still breaks on SDIO
hardware, because SDIO hardware access needs to sleep, but we are not allowed
to sleep in the callback due to mac80211's RCU locking.

Signed-off-by: default avatarMichael Buesch <mb@bu3sch.de>
Tested-by: default avatarLarry Finger <Larry.Finger@lwfinger.net>
Reported-by: default avatar <kecsa@kutfo.hit.bme.hu>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: stable <stable@kernel.org>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 65896510

drivers/net/wireless/b43/main.c

+5 −8
Original line number Diff line number Diff line
@@ -856,22 +856,19 @@ static void b43_op_update_tkip_key(struct ieee80211_hw *hw, 
	if (B43_WARN_ON(!modparam_hwtkip))

		return;



	mutex_lock(&wl->mutex);



	/* This is only called from the RX path through mac80211, where

	 * our mutex is already locked. */

	B43_WARN_ON(!mutex_is_locked(&wl->mutex));

	dev = wl->current_dev;

	if (!dev || b43_status(dev) < B43_STAT_INITIALIZED)

		goto out_unlock;

	B43_WARN_ON(!dev || b43_status(dev) < B43_STAT_INITIALIZED);



	keymac_write(dev, index, NULL);	/* First zero out mac to avoid race */



	rx_tkip_phase1_write(dev, index, iv32, phase1key);

	/* only pairwise TKIP keys are supported right now */

	if (WARN_ON(!sta))

		goto out_unlock;

		return;

	keymac_write(dev, index, sta->addr);



out_unlock:

	mutex_unlock(&wl->mutex);

}



static void do_key_write(struct b43_wldev *dev,