Re: [PATCH v1] iio: temperature: hid-sensor-temperature: switch to non-devm iio_device_register()

[srinivas pandruvada]

On Mon, 2026-06-22 at 10:51 +0530, Sanjay Chitroda wrote:
> From: Sanjay Chitroda <sanjayembeddedse@xxxxxxxxx>
> 
> Avoid using devm_iio_device_register(), as this driver requires
> explicit
> error handling and teardown ordering.
> 
> Mixing devm_* APIs with goto-based error unwinding breaks the
> expected
> LIFO resource release model and can introduce race windows during
> device
> removal. In particular, the IIO device may remain visible to
> userspace
> while dependent resources are already being freed, potentially
> leading
> to use-after-free issues.

Please explain this use after free case here.

Thanks,
Srinivas

> 
> Add explicit iio_device_unregister() call in the teardown path to
> ensure
> deterministic cleanup and follow kernel resource management
> conventions.
> 
> Fixes: 59d0f2da3569 ("iio: hid: Add temperature sensor support")
> Signed-off-by: Sanjay Chitroda <sanjayembeddedse@xxxxxxxxx>
> ---
>  drivers/iio/temperature/hid-sensor-temperature.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iio/temperature/hid-sensor-temperature.c
> b/drivers/iio/temperature/hid-sensor-temperature.c
> index 9f628a8e5cfb..34bff7e9f3a3 100644
> --- a/drivers/iio/temperature/hid-sensor-temperature.c
> +++ b/drivers/iio/temperature/hid-sensor-temperature.c
> @@ -244,7 +244,7 @@ static int hid_temperature_probe(struct
> platform_device *pdev)
>  	if (ret)
>  		goto error_remove_trigger;
>  
> -	ret = devm_iio_device_register(indio_dev->dev.parent,
> indio_dev);
> +	ret = iio_device_register(indio_dev);
>  	if (ret)
>  		goto error_remove_callback;
>  
> @@ -264,6 +264,7 @@ static void hid_temperature_remove(struct
> platform_device *pdev)
>  	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
>  	struct temperature_state *temp_st = iio_priv(indio_dev);
>  
> +	iio_device_unregister(indio_dev);
>  	sensor_hub_remove_callback(hsdev,
> HID_USAGE_SENSOR_TEMPERATURE);
>  	hid_sensor_remove_trigger(indio_dev, &temp_st-
> >common_attributes);
>  }