Patch "gpiolib: Fix NULL pointer deference" has been added to the 4.6-stable tree

Patch "gpiolib: Fix NULL pointer deference" has been added to the 4.6-stable tree

[gregkh]

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

    gpiolib: Fix NULL pointer deference

to the 4.6-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:
     gpiolib-fix-null-pointer-deference.patch
and it can be found in the queue-4.6 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 11f33a6d15bfa397867ac0d7f3481b6dd683286f Mon Sep 17 00:00:00 2001
From: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Date: Fri, 3 Jun 2016 19:10:01 +0200
Subject: gpiolib: Fix NULL pointer deference

From: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>

commit 11f33a6d15bfa397867ac0d7f3481b6dd683286f upstream.

Under some circumstances, a gpiochip might be half cleaned from the
gpio_device list.

This patch makes sure that the chip pointer is still valid, before
calling the match function.

[  104.088296] BUG: unable to handle kernel NULL pointer dereference at
0000000000000090
[  104.089772] IP: [<ffffffff813d2045>] of_gpiochip_find_and_xlate+0x15/0x80
[  104.128273] Call Trace:
[  104.129802]  [<ffffffff813d2030>] ? of_parse_own_gpio+0x1f0/0x1f0
[  104.131353]  [<ffffffff813cd910>] gpiochip_find+0x60/0x90
[  104.132868]  [<ffffffff813d21ba>] of_get_named_gpiod_flags+0x9a/0x120
...
[  104.141586]  [<ffffffff8163d12b>] gpio_led_probe+0x11b/0x360

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/gpio/gpiolib.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -841,7 +841,7 @@ struct gpio_chip *gpiochip_find(void *da
 
 	spin_lock_irqsave(&gpio_lock, flags);
 	list_for_each_entry(gdev, &gpio_devices, list)
-		if (match(gdev->chip, data))
+		if (gdev->chip && match(gdev->chip, data))
 			break;
 
 	/* No match? */


Patches currently in stable-queue which might be from ricardo.ribalda@gmail.com are

queue-4.6/gpiolib-fix-unaligned-used-of-reference-counters.patch
queue-4.6/gpiolib-fix-null-pointer-deference.patch