iwlwifi: mvm: avoid crash on restart w/o reserved queues

commit 03c902bf upstream.

When the firmware restarts in a situation in which any station
has no queue reserved anymore because that queue was used, the
code will crash trying to access the queue_info array at the
offset 255, which is far too big. Fix this by checking that a
queue is actually reserved before writing its status.

Fixes: 8d98ae6e ("iwlwifi: mvm: re-assign old queues after hw restart in dqa mode")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/net/wireless/intel/iwlwifi/mvm/sta.c

@@ -1144,9 +1144,10 @@ static void iwl_mvm_realloc_queues_after_restart(struct iwl_mvm *mvm,
 		.frame_limit = IWL_FRAME_LIMIT,
 	};
 
-	/* Make sure reserved queue is still marked as such (or allocated) */
-	mvm->queue_info[mvm_sta->reserved_queue].status =
-		IWL_MVM_QUEUE_RESERVED;
+	/* Make sure reserved queue is still marked as such (if allocated) */
+	if (mvm_sta->reserved_queue != IEEE80211_INVAL_HW_QUEUE)
+		mvm->queue_info[mvm_sta->reserved_queue].status =
+			IWL_MVM_QUEUE_RESERVED;
 
 	for (i = 0; i <= IWL_MAX_TID_COUNT; i++) {
 		struct iwl_mvm_tid_data *tid_data = &mvm_sta->tid_data[i];