1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/tty/serial/pxa.c b/drivers/tty/serial/pxa.c
index 21b7d8b86493..7788d53281a0 100644
--- a/drivers/tty/serial/pxa.c
+++ b/drivers/tty/serial/pxa.c
@@ -223,6 +223,7 @@ static void serial_pxa_start_tx(struct uart_port *port)
         }
 }
 
+/* should hold up->port.lock */
 static inline void check_modem_status(struct uart_pxa_port *up)
 {
         int status;
@@ -255,12 +256,14 @@ static inline irqreturn_t serial_pxa_irq(int irq, void *dev_id)
         iir = serial_in(up, UART_IIR);
         if (iir & UART_IIR_NO_INT)
                 return IRQ_NONE;
+        spin_lock(&up->port.lock);
         lsr = serial_in(up, UART_LSR);
         if (lsr & UART_LSR_DR)
                 receive_chars(up, &lsr);
         check_modem_status(up);
         if (lsr & UART_LSR_THRE)
                 transmit_chars(up);
+        spin_unlock(&up->port.lock);
         return IRQ_HANDLED;
 }