Commit 869ffbd5 authored Jun 03, 2016 by Ricardo Ribalda Delgado Committed by Sasha Levin Jun 19, 2016

gpiolib: Fix NULL pointer deference



[ Upstream commit 11f33a6d15bfa397867ac0d7f3481b6dd683286f ]

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

Cc: stable@vger.kernel.org
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

parent 34558d3f

drivers/gpio/gpiolib.c

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -356,7 +356,7 @@ struct gpio_chip gpiochip_find(void data,

	spin_lock_irqsave(&gpio_lock, flags);		spin_lock_irqsave(&gpio_lock, flags);
	list_for_each_entry(chip, &gpio_chips, list)		list_for_each_entry(chip, &gpio_chips, list)
	if (match(chip, data))		if (chip && match(chip, data))
	break;		break;

	/* No match? */		/* No match? */