diff --git a/drivers/tty/serial/jsm/jsm_neo.c b/drivers/tty/serial/jsm/jsm_neo.c
index bf0e2a4cb0cef..c6f927a76c3be 100644
--- a/drivers/tty/serial/jsm/jsm_neo.c
+++ b/drivers/tty/serial/jsm/jsm_neo.c
@@ -815,7 +815,9 @@ static void neo_parse_isr(struct jsm_board *brd, u32 port)
 		/* Parse any modem signal changes */
 		jsm_dbg(INTR, &ch->ch_bd->pci_dev,
 			"MOD_STAT: sending to parse_modem_sigs\n");
+		spin_lock_irqsave(&ch->uart_port.lock, lock_flags);
 		neo_parse_modem(ch, readb(&ch->ch_neo_uart->msr));
+		spin_unlock_irqrestore(&ch->uart_port.lock, lock_flags);
 	}
 }
 
diff --git a/drivers/tty/serial/jsm/jsm_tty.c b/drivers/tty/serial/jsm/jsm_tty.c
index 8e42a7682c63d..d74cbbbf33c62 100644
--- a/drivers/tty/serial/jsm/jsm_tty.c
+++ b/drivers/tty/serial/jsm/jsm_tty.c
@@ -187,6 +187,7 @@ static void jsm_tty_break(struct uart_port *port, int break_state)
 
 static int jsm_tty_open(struct uart_port *port)
 {
+	unsigned long lock_flags;
 	struct jsm_board *brd;
 	struct jsm_channel *channel =
 		container_of(port, struct jsm_channel, uart_port);
@@ -240,6 +241,7 @@ static int jsm_tty_open(struct uart_port *port)
 	channel->ch_cached_lsr = 0;
 	channel->ch_stops_sent = 0;
 
+	spin_lock_irqsave(&port->lock, lock_flags);
 	termios = &port->state->port.tty->termios;
 	channel->ch_c_cflag	= termios->c_cflag;
 	channel->ch_c_iflag	= termios->c_iflag;
@@ -259,6 +261,7 @@ static int jsm_tty_open(struct uart_port *port)
 	jsm_carrier(channel);
 
 	channel->ch_open_count++;
+	spin_unlock_irqrestore(&port->lock, lock_flags);
 
 	jsm_dbg(OPEN, &channel->ch_bd->pci_dev, "finish\n");
 	return 0;