patch "serial: core: fix crash in uart_suspend_port" added to tty-linus

patch "serial: core: fix crash in uart_suspend_port" added to tty-linus

[gregkh]

This is a note to let you know that I've just added the patch titled

    serial: core: fix crash in uart_suspend_port

to my tty git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git
in the tty-linus branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.

If you have any questions about this process, please let me know.


>From 88e2582e90bb89fe895ff0dceeb5d5ab65d07997 Mon Sep 17 00:00:00 2001
From: Lucas Stach <l.stach@pengutronix.de>
Date: Thu, 11 May 2017 12:56:14 +0200
Subject: serial: core: fix crash in uart_suspend_port

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 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 0f45b7884a2c..bc6caea6099f 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -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);
-- 
2.13.0