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From: Bartosz Golaszewski <brgl@bgdev.pl>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org,
	Bartosz Golaszewski <bgolaszewski@baylibre.com>,
	Kent Gibson <warthog618@gmail.com>
Subject: [PATCH] gpiolib: fix bitmap operations related to line event watching
Date: Wed, 26 Feb 2020 14:53:23 +0100	[thread overview]
Message-ID: <20200226135323.1840-1-brgl@bgdev.pl> (raw)

From: Bartosz Golaszewski <bgolaszewski@baylibre.com>

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: 51c1064e82e7 ("gpiolib: add new ioctl() for monitoring changes in line info")
Reported-by: Kent Gibson <warthog618@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
---
 drivers/gpio/gpiolib.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index a5cd1b4abe6f..5cc80f6f79e0 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -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));
-- 
2.25.0


             reply	other threads:[~2020-02-26 13:53 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-26 13:53 Bartosz Golaszewski [this message]
2020-02-26 14:57 ` [PATCH] gpiolib: fix bitmap operations related to line event watching Kent Gibson
2020-02-28 23:20 ` Linus Walleij
2020-02-29 13:43   ` Bartosz Golaszewski

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