From: Vladimir Zapolskiy <vz@mleia.com>
Date: Thu, 21 Dec 2017 16:37:24 +0000 (+0200)
Subject: gpiolib: don't dereference a desc before validation
X-Git-Tag: v4.15.17~144
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ffc544a91a0f9040a79fda8c2cb051fefa43212b;p=thirdparty%2Fkernel%2Fstable.git

gpiolib: don't dereference a desc before validation


[ Upstream commit 30322bcf82d74cad0d6e1cf9ba7fa7fa48c7a026 ]

The fix restores a proper validation of an input gpio desc, which
might be needed to deal with optional GPIOs correctly.

Fixes: 02e479808b5d ("gpio: Alter semantics of *raw* operations to actually be raw")
Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 7a5cf5b08c54f..00d0060435856 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -2468,7 +2468,7 @@ EXPORT_SYMBOL_GPL(gpiod_direction_output_raw);
  */
 int gpiod_direction_output(struct gpio_desc *desc, int value)
 {
-	struct gpio_chip *gc = desc->gdev->chip;
+	struct gpio_chip *gc;
 	int ret;
 
 	VALIDATE_DESC(desc);
@@ -2485,6 +2485,7 @@ int gpiod_direction_output(struct gpio_desc *desc, int value)
 		return -EIO;
 	}
 
+	gc = desc->gdev->chip;
 	if (test_bit(FLAG_OPEN_DRAIN, &desc->flags)) {
 		/* First see if we can enable open drain in hardware */
 		ret = gpio_set_drive_single_ended(gc, gpio_chip_hwgpio(desc),