Commit 19314797 authored by Bartosz Golaszewski's avatar Bartosz Golaszewski
Browse files

gpiolib: fix bitmap operations related to line event watching 



When operating on the bits of watched_lines bitmap, we're using
desc_to_gpio() which returns the GPIO number from the global numberspace.
This leads to all sorts of memory corruptions and invalid behavior. We
should switch to using gpio_chip_hwgpio() instead.

Fixes: 51c1064e ("gpiolib: add new ioctl() for monitoring changes in line info")
Reported-by: default avatarKent Gibson <warthog618@gmail.com>
Signed-off-by: default avatarBartosz Golaszewski <bgolaszewski@baylibre.com>
Tested-by: default avatarKent Gibson <warthog618@gmail.com>
parent 48543bd8

drivers/gpio/gpiolib.c

+3 −3
Original line number Diff line number Diff line
@@ -1261,7 +1261,7 @@ static long gpio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 
			return -EFAULT;



		if (cmd == GPIO_GET_LINEINFO_WATCH_IOCTL)

			set_bit(desc_to_gpio(desc), priv->watched_lines);

			set_bit(gpio_chip_hwgpio(desc), priv->watched_lines);



		return 0;

	} else if (cmd == GPIO_GET_LINEHANDLE_IOCTL) {
@@ -1276,7 +1276,7 @@ static long gpio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 
		if (IS_ERR(desc))

			return PTR_ERR(desc);



		clear_bit(desc_to_gpio(desc), priv->watched_lines);

		clear_bit(gpio_chip_hwgpio(desc), priv->watched_lines);

		return 0;

	}

	return -EINVAL;
@@ -1304,7 +1304,7 @@ static int lineinfo_changed_notify(struct notifier_block *nb, 
	struct gpio_desc *desc = data;

	int ret;



	if (!test_bit(desc_to_gpio(desc), priv->watched_lines))

	if (!test_bit(gpio_chip_hwgpio(desc), priv->watched_lines))

		return NOTIFY_DONE;



	memset(&chg, 0, sizeof(chg));