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: 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
......@@ -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,
......
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