serial: core: fix crash in uart_suspend_port
authorLucas Stach <l.stach@pengutronix.de>
Thu, 11 May 2017 10:56:14 +0000 (12:56 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 18 May 2017 14:43:55 +0000 (16:43 +0200)
With serdev we might end up with serial ports that have no cdev exported
to userspace, as they are used as the bus interface to other devices. In
that case serial_match_port() won't be able to find a matching tty_dev.

Skip the irq wakeup enabling in that case, as serdev will make sure to
keep the port active, as long as there are devices depending on it.

Fixes: 8ee3fde04758 (tty_port: register tty ports with serdev bus)
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/tty/serial/serial_core.c

index 0f45b78..bc6caea 100644 (file)
@@ -2083,7 +2083,7 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport)
        mutex_lock(&port->mutex);
 
        tty_dev = device_find_child(uport->dev, &match, serial_match_port);
-       if (device_may_wakeup(tty_dev)) {
+       if (tty_dev && device_may_wakeup(tty_dev)) {
                if (!enable_irq_wake(uport->irq))
                        uport->irq_wake = 1;
                put_device(tty_dev);