--- x/drivers/tty/n_gsm.c
+++ n/drivers/tty/n_gsm.c
@@ -2608,6 +2608,8 @@ static struct gsm_mux *gsm_alloc_mux(voi
 		return NULL;
 	}
 	spin_lock_init(&gsm->lock);
+	spin_lock_init(&gsm->control_lock);
+	spin_lock_init(&gsm->tx_lock);
 	mutex_init(&gsm->mutex);
 	kref_init(&gsm->ref);
 	INIT_LIST_HEAD(&gsm->tx_ctrl_list);