mac80211: add a fix to prevent unsafe queue wake calls during restart

Signed-off-by: Felix Fietkau <nbd@nbd.name>

package/kernel/mac80211/patches/subsys/301-mac80211-do-not-call-driver-wake_tx_queue-op-during-.patch

@@ -0,0 +1,33 @@
+From: Felix Fietkau <nbd@nbd.name>
+Date: Fri, 1 Mar 2019 14:42:56 +0100
+Subject: [PATCH] mac80211: do not call driver wake_tx_queue op during reconfig
+
+There are several scenarios in which mac80211 can call drv_wake_tx_queue
+after ieee80211_restart_hw has been called and has not yet completed.
+Driver private structs are considered uninitialized until mac80211 has
+uploaded the vifs, stations and keys again, so using private tx queue
+data during that time is not safe.
+
+The driver can also not rely on drv_reconfig_complete to figure out when
+it is safe to accept drv_wake_tx_queue calls again, because it is only
+called after all tx queues are woken again.
+
+To fix this, bail out early in drv_wake_tx_queue if local->in_reconfig
+is set.
+
+Cc: stable@vger.kernel.org
+Signed-off-by: Felix Fietkau <nbd@nbd.name>
+---
+
+--- a/net/mac80211/driver-ops.h
++++ b/net/mac80211/driver-ops.h
+@@ -1166,6 +1166,9 @@ static inline void drv_wake_tx_queue(str
+ {
+ 	struct ieee80211_sub_if_data *sdata = vif_to_sdata(txq->txq.vif);
+ 
++	if (local->in_reconfig)
++		return;
++
+ 	if (!check_sdata_in_driver(sdata))
+ 		return;
+