mac80211: fix txq queue related crashes

The driver can access the queue simultanously
while mac80211 tears down the interface. Without
spinlock protection this could lead to corrupting
sk_buff_head and subsequently to an invalid
pointer dereference.

Fixes: ba8c3d6f16a1 ("mac80211: add an intermediate software queue implementation")
Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index 33ae3c81bfc581218c48b6ab0061e3587dbf205d..0451f120746ec8155dce1eca967121c6228a7ab8 100644 (file)
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -977,7 +977,10 @@ static void ieee80211_do_stop(struct ieee80211_sub_if_data *sdata,
        if (sdata->vif.txq) {
                struct txq_info *txqi = to_txq_info(sdata->vif.txq);
 
+               spin_lock_bh(&txqi->queue.lock);
                ieee80211_purge_tx_queue(&local->hw, &txqi->queue);
+               spin_unlock_bh(&txqi->queue.lock);
+
                atomic_set(&sdata->txqs_len[txqi->txq.ac], 0);
        }