gpiolib: Fix unaligned used of reference counters (f4833b8c) · Commits · 戴 / test

gpiolib relies on the reference counters to clean up the gpio_device structure. Although the number of get/put is properly aligned on gpiolib.c itself, it does not take into consideration how the referece counters are affected by other external functions such as cdev_add and device_add. Because of this, after the last call to put_device, the reference counter has a value of +3, therefore never calling gpiodevice_release. Due to the fact that some of the device has already been cleaned on gpiochip_remove, the library will end up OOPsing the kernel (e.g. a call to of_gpiochip_find_and_xlate). Cc: stable@vger.kernel.org Signed-off-by:

Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> Signed-off-by:

Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpiolib.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -449,7 +449,6 @@ static void gpiodevice_release(struct device *dev)
		{
		struct gpio_device *gdev = dev_get_drvdata(dev);

		cdev_del(&gdev->chrdev);
		list_del(&gdev->list);
		ida_simple_remove(&gpio_ida, gdev->id);
		kfree(gdev->label);
		@@ -482,7 +481,6 @@ static int gpiochip_setup_dev(struct gpio_device *gdev)

		/* From this point, the .release() function cleans up gpio_device */
		gdev->dev.release = gpiodevice_release;
		get_device(&gdev->dev);
		pr_debug("%s: registered GPIOs %d to %d on device: %s (%s)\n",
		__func__, gdev->base, gdev->base + gdev->ngpio - 1,
		dev_name(&gdev->dev), gdev->chip->label ? : "generic");
		@@ -770,6 +768,8 @@ void gpiochip_remove(struct gpio_chip *chip)
		* be removed, else it will be dangling until the last user is
		* gone.
		*/
		cdev_del(&gdev->chrdev);
		device_del(&gdev->dev);
		put_device(&gdev->dev);
		}
		EXPORT_SYMBOL_GPL(gpiochip_remove);

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