From: Sherry Sun <sherry.sun@xxxxxxx> commit 178e00f36f934a88682d96aa046c1f90cb6f83a7 upstream. 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") Cc: stable <stable@xxxxxxxxxx> Signed-off-by: Sherry Sun <sherry.sun@xxxxxxx> Link: https://lore.kernel.org/r/20230323110923.24581-1-sherry.sun@xxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/tty/serial/fsl_lpuart.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/tty/serial/fsl_lpuart.c +++ b/drivers/tty/serial/fsl_lpuart.c @@ -2896,7 +2896,7 @@ static bool lpuart_uport_is_active(struc 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); }