diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index a864a93f9cec19d80d9ce65d53cf73d89d1e8437..18ff237313493b74a68846a62da63f72887b4d45 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -2164,6 +2164,7 @@ static void gsm_cleanup_mux(struct gsm_mux *gsm, bool disc)
 	int i;
 	struct gsm_dlci *dlci;
 	struct gsm_msg *txq, *ntxq;
+	unsigned long flags;
 
 	gsm->dead = true;
 	mutex_lock(&gsm->mutex);
@@ -2186,10 +2187,13 @@ static void gsm_cleanup_mux(struct gsm_mux *gsm, bool disc)
 			gsm_dlci_release(gsm->dlci[i]);
 	mutex_unlock(&gsm->mutex);
 	/* Now wipe the queues */
+
+	spin_lock_irqsave(&gsm->tx_lock, flags);
 	tty_ldisc_flush(gsm->tty);
 	list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list)
 		kfree(txq);
 	INIT_LIST_HEAD(&gsm->tx_list);
+	spin_unlock_irqrestore(&gsm->tx_lock, flags);
 }
 
 /**