media: i2c: ar0521: Check return value of devm_gpiod_get_optional() in ar0521_probe()

[PATCH] media: i2c: ar0521: Check return value of devm_gpiod_get_optional() in ar0521_probe()

Posted by Chen Ni 1 week, 2 days ago

The devm_gpiod_get_optional() function may return an error pointer
(ERR_PTR) in case of a genuine failure during GPIO acquisition, not just
NULL which indicates the legitimate absence of an optional GPIO.

Add an IS_ERR() check after the function call to catch such errors and
propagate them to the probe function, ensuring the driver fails to load
safely rather than proceeding with an invalid pointer.

Signed-off-by: Chen Ni <nichen@iscas.ac.cn>
---
 drivers/media/i2c/ar0521.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/media/i2c/ar0521.c b/drivers/media/i2c/ar0521.c
index f156058500e3..ed324c2d87aa 100644
--- a/drivers/media/i2c/ar0521.c
+++ b/drivers/media/i2c/ar0521.c
@@ -1094,6 +1094,9 @@ static int ar0521_probe(struct i2c_client *client)
 	/* Request optional reset pin (usually active low) and assert it */
 	sensor->reset_gpio = devm_gpiod_get_optional(dev, "reset",
 						     GPIOD_OUT_HIGH);
+	if (IS_ERR(sensor->reset_gpio))
+		return dev_err_probe(dev, PTR_ERR(sensor->reset_gpio),
+				     "failed to get reset gpio\n");
 
 	v4l2_i2c_subdev_init(&sensor->sd, client, &ar0521_subdev_ops);
 
-- 
2.25.1

Re: [PATCH] media: i2c: ar0521: Check return value of devm_gpiod_get_optional() in ar0521_probe()

Posted by Krzysztof Hałasa 2 days, 19 hours ago

Hi Chen,

Chen Ni <nichen@iscas.ac.cn> writes:

> The devm_gpiod_get_optional() function may return an error pointer
> (ERR_PTR) in case of a genuine failure during GPIO acquisition, not just
> NULL which indicates the legitimate absence of an optional GPIO.

Well, it seems only right. Though I would prefer all-caps "GPIO" in
kernel messages. Either way,

Acked-by: Krzysztof Hałasa <khalasa@piap.pl>

> --- a/drivers/media/i2c/ar0521.c
> +++ b/drivers/media/i2c/ar0521.c
> @@ -1094,6 +1094,9 @@ static int ar0521_probe(struct i2c_client *client)
>         /* Request optional reset pin (usually active low) and assert it */
>         sensor->reset_gpio = devm_gpiod_get_optional(dev, "reset",
>                                                      GPIOD_OUT_HIGH);
> +       if (IS_ERR(sensor->reset_gpio))
> +               return dev_err_probe(dev, PTR_ERR(sensor->reset_gpio),
> +                                    "failed to get reset gpio\n");
>
>         v4l2_i2c_subdev_init(&sensor->sd, client, &ar0521_subdev_ops);
>

-- 
Krzysztof "Chris" Hałasa

Sieć Badawcza Łukasiewicz
Przemysłowy Instytut Automatyki i Pomiarów PIAP
Al. Jerozolimskie 202, 02-486 Warszawa

Re: [PATCH] media: i2c: ar0521: Check return value of devm_gpiod_get_optional() in ar0521_probe()

Posted by Markus Elfring 1 week, 1 day ago

…
> Add an IS_ERR() check after the function call to catch such errors and
> propagate them to the probe function, ensuring the driver fails to load
> safely rather than proceeding with an invalid pointer.

* Were any source code analysis tools involved here?

* Did anything hinder to add any tags (like “Fixes” and “Cc”) accordingly?


Regards,
Markus