Patch "gpio: bail out silently on NULL descriptors" has been added to the 4.6-stable tree

[<gregkh@linuxfoundation.org>]

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

    gpio: bail out silently on NULL descriptors

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:
     gpio-bail-out-silently-on-null-descriptors.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 54d77198fdfbc4f0fe11b4252c1d9c97d51a3264 Mon Sep 17 00:00:00 2001
From: Linus Walleij <linus.walleij@linaro.org>
Date: Mon, 30 May 2016 16:48:39 +0200
Subject: gpio: bail out silently on NULL descriptors
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

From: Linus Walleij <linus.walleij@linaro.org>

commit 54d77198fdfbc4f0fe11b4252c1d9c97d51a3264 upstream.

In fdeb8e1547cb9dd39d5d7223b33f3565cf86c28e
("gpio: reflect base and ngpio into gpio_device")
assumed that GPIO descriptors are either valid or error
pointers, but gpiod_get_[index_]optional() actually return
NULL descriptors and then all subsequent calls should just
bail out.

Cc: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Andrew Lunn <andrew@lunn.ch>
Fixes: fdeb8e1547cb ("gpio: reflect base and ngpio into gpio_device")
Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/gpio/gpiolib.c |   11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1339,10 +1339,13 @@ done:
 /*
  * This descriptor validation needs to be inserted verbatim into each
  * function taking a descriptor, so we need to use a preprocessor
- * macro to avoid endless duplication.
+ * macro to avoid endless duplication. If the desc is NULL it is an
+ * optional GPIO and calls should just bail out.
  */
 #define VALIDATE_DESC(desc) do { \
-	if (!desc || !desc->gdev) { \
+	if (!desc) \
+		return 0; \
+	if (!desc->gdev) { \
 		pr_warn("%s: invalid GPIO\n", __func__); \
 		return -EINVAL; \
 	} \
@@ -1353,7 +1356,9 @@ done:
 	} } while (0)
 
 #define VALIDATE_DESC_VOID(desc) do { \
-	if (!desc || !desc->gdev) { \
+	if (!desc) \
+		return; \
+	if (!desc->gdev) { \
 		pr_warn("%s: invalid GPIO\n", __func__); \
 		return; \
 	} \


Patches currently in stable-queue which might be from linus.walleij@linaro.org are

queue-4.6/gpiolib-fix-unaligned-used-of-reference-counters.patch
queue-4.6/gpio-bcm-kona-fix-bcm_kona_gpio_reset-warnings.patch
queue-4.6/pinctrl-mediatek-fix-dual-edge-code-defect.patch
queue-4.6/gpio-bail-out-silently-on-null-descriptors.patch
queue-4.6/gpiolib-fix-null-pointer-deference.patch