Patch "serial: core: fix crash in uart_suspend_port" has been added to the 4.11-stable tree

Patch "serial: core: fix crash in uart_suspend_port" has been added to the 4.11-stable tree

[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 the 4.11-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     serial-core-fix-crash-in-uart_suspend_port.patch
and it can be found in the queue-4.11 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>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

From: Lucas Stach <l.stach@pengutronix.de>

commit 88e2582e90bb89fe895ff0dceeb5d5ab65d07997 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/tty/serial/serial_core.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- 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
 	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);


Patches currently in stable-queue which might be from l.stach@pengutronix.de are

queue-4.11/serial-core-fix-crash-in-uart_suspend_port.patch