tty: serial: fsl_lpuart: fix crash in lpuart_uport_is_active

BugLink: https://bugs.launchpad.net/bugs/2016879
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@kernel.org>
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20230323110923.24581-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index f58f57ad7fbe1488e1fa12f3f097e6fb8ff9aa92..59c10bceebbeff5d44741dee01bb205612d656a9 100644 (file)
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -2896,7 +2896,7 @@ 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);
        }