For serdev framework, tty->dev is a NULL pointer, lpuart_uport_is_active
calling device_may_wakeup() may cause kernel NULL pointer crash, so here
add the NULL pointer check before using it.

Fixes: 4f5cb8c5e915 ("tty: serial: fsl_lpuart: enable wakeup source for lpuart")
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
---
 drivers/tty/serial/fsl_lpuart.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index 3281e81e1723..8daac87d063c 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -3022,7 +3022,7 @@ static bool lpuart_uport_is_active(struct lpuart_port *sport)
 	tty = tty_port_tty_get(port);
 	if (tty) {
 		tty_dev = tty->dev;
-		may_wake = device_may_wakeup(tty_dev);
+		may_wake = tty_dev && device_may_wakeup(tty_dev);
 		tty_kref_put(tty);
 	}
 
-- 
2.17.1