gpio: cdev: avoid uninitialized variable dereference

[PATCH] gpio: cdev: avoid uninitialized variable dereference

Posted by Arnd Bergmann 1 year, 11 months ago

From: Arnd Bergmann <arnd@arndb.de>

The 'gc' variable is never set before it gets printed:

drivers/gpio/gpiolib-cdev.c:2802:11: error: variable 'gc' is uninitialized when used here [-Werror,-Wuninitialized]
 2802 |         chip_dbg(gc, "added GPIO chardev (%d:%d)\n", MAJOR(devt), gdev->id);
      |                  ^~
drivers/gpio/gpiolib.h:277:11: note: expanded from macro 'chip_dbg'
  277 |         dev_dbg(&gc->gpiodev->dev, "(%s): " fmt, gc->label, ##__VA_ARGS__)
      |                  ^~

Use dev_dbg() directly.

Fixes: 8574b5b47610 ("gpio: cdev: use correct pointer accessors with SRCU")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/gpio/gpiolib-cdev.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
index 85037fa4925e..d6e8d2b7ac8f 100644
--- a/drivers/gpio/gpiolib-cdev.c
+++ b/drivers/gpio/gpiolib-cdev.c
@@ -2783,7 +2783,6 @@ static const struct file_operations gpio_fileops = {
 
 int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt)
 {
-	struct gpio_chip *gc;
 	int ret;
 
 	cdev_init(&gdev->chrdev, &gpio_fileops);
@@ -2799,7 +2798,7 @@ int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt)
 	if (!rcu_access_pointer(gdev->chip))
 		return -ENODEV;
 
-	chip_dbg(gc, "added GPIO chardev (%d:%d)\n", MAJOR(devt), gdev->id);
+	dev_dbg(&gdev->dev, "added GPIO chardev (%d:%d)\n", MAJOR(devt), gdev->id);
 
 	return 0;
 }
-- 
2.39.2

Re: [PATCH] gpio: cdev: avoid uninitialized variable dereference

Posted by Bartosz Golaszewski 1 year, 11 months ago

On Fri, Feb 16, 2024 at 2:00 PM Arnd Bergmann <arnd@kernel.org> wrote:
>
> From: Arnd Bergmann <arnd@arndb.de>
>
> The 'gc' variable is never set before it gets printed:
>
> drivers/gpio/gpiolib-cdev.c:2802:11: error: variable 'gc' is uninitialized when used here [-Werror,-Wuninitialized]
>  2802 |         chip_dbg(gc, "added GPIO chardev (%d:%d)\n", MAJOR(devt), gdev->id);
>       |                  ^~
> drivers/gpio/gpiolib.h:277:11: note: expanded from macro 'chip_dbg'
>   277 |         dev_dbg(&gc->gpiodev->dev, "(%s): " fmt, gc->label, ##__VA_ARGS__)
>       |                  ^~
>
> Use dev_dbg() directly.
>
> Fixes: 8574b5b47610 ("gpio: cdev: use correct pointer accessors with SRCU")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---

Hi Arnd,

I seem to have beat you to it[1] and my patch doesn't change the log
message so I'll apply it instead of this one.

Thanks,
Bartosz

[1] https://lore.kernel.org/linux-gpio/1542ef65-508b-45be-ad5c-63ad124cb1a2@samsung.com/T/#t