diff --git a/drivers/tty/serial/serial_mctrl_gpio.c b/drivers/tty/serial/serial_mctrl_gpio.c
index 02147361eaa94747aea5d7f7235fc61c6cd92109..9e1086f7f22a9c45f708f1126d0ff0298b9b2c8b 100644
--- a/drivers/tty/serial/serial_mctrl_gpio.c
+++ b/drivers/tty/serial/serial_mctrl_gpio.c
@@ -125,9 +125,12 @@ static irqreturn_t mctrl_gpio_irq_handle(int irq, void *context)
 	struct uart_port *port = gpios->port;
 	u32 mctrl = gpios->mctrl_prev;
 	u32 mctrl_diff;
+	unsigned long flags;
 
 	mctrl_gpio_get(gpios, &mctrl);
 
+	spin_lock_irqsave(&port->lock, flags);
+
 	mctrl_diff = mctrl ^ gpios->mctrl_prev;
 	gpios->mctrl_prev = mctrl;
 
@@ -147,6 +150,8 @@ static irqreturn_t mctrl_gpio_irq_handle(int irq, void *context)
 		wake_up_interruptible(&port->state->port.delta_msr_wait);
 	}
 
+	spin_unlock_irqrestore(&port->lock, flags);
+
 	return IRQ_HANDLED;
 }