Re: [PATCH 2/9] iio: orientation: hid-sensor-incl-3d: Fix race between callback registration and device exposure

[Pandruvada, Srinivas]

On Sat, 2026-06-06 at 17:07 +0530, Sanjay Chitroda wrote:
> From: Sanjay Chitroda <sanjayembeddedse@xxxxxxxxx>
> 
> The driver registers the IIO device before completing sensor hub
> callback registration and unregisters callbacks while the IIO device
> is still exposed during teardown.
> 
> This creates race windows in both probe and remove paths, which can
> lead to NULL pointer dereferences or use-after-free.

Reordering is fine, but can you show how this use after free is
possible?

Thanks,
Srinivas

> 
> Fix this by correct ordering of callback registration and
> IIO device registration in probe and remove paths.
> 
> Fixes: 098d3beccfb6 ("iio: hid-sensors: Added Inclinometer 3D")
> Signed-off-by: Sanjay Chitroda <sanjayembeddedse@xxxxxxxxx>
> ---
>  drivers/iio/orientation/hid-sensor-incl-3d.c | 20 ++++++++++--------
> --
>  1 file changed, 10 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/iio/orientation/hid-sensor-incl-3d.c
> b/drivers/iio/orientation/hid-sensor-incl-3d.c
> index 4e23a598a3fb..5e3d2bb9b5bf 100644
> --- a/drivers/iio/orientation/hid-sensor-incl-3d.c
> +++ b/drivers/iio/orientation/hid-sensor-incl-3d.c
> @@ -356,12 +356,6 @@ static int hid_incl_3d_probe(struct
> platform_device *pdev)
>  		return ret;
>  	}
>  
> -	ret = iio_device_register(indio_dev);
> -	if (ret) {
> -		dev_err(&pdev->dev, "device register failed\n");
> -		goto error_remove_trigger;
> -	}
> -
>  	incl_state->callbacks.send_event = incl_3d_proc_event;
>  	incl_state->callbacks.capture_sample =
> incl_3d_capture_sample;
>  	incl_state->callbacks.pdev = pdev;
> @@ -370,13 +364,19 @@ static int hid_incl_3d_probe(struct
> platform_device *pdev)
>  					&incl_state->callbacks);
>  	if (ret) {
>  		dev_err(&pdev->dev, "callback reg failed\n");
> -		goto error_iio_unreg;
> +		goto error_remove_trigger;
> +	}
> +
> +	ret = iio_device_register(indio_dev);
> +	if (ret) {
> +		dev_err(&pdev->dev, "device register failed\n");
> +		goto error_remove_callback;
>  	}
>  
>  	return 0;
>  
> -error_iio_unreg:
> -	iio_device_unregister(indio_dev);
> +error_remove_callback:
> +	sensor_hub_remove_callback(hsdev,
> HID_USAGE_SENSOR_INCLINOMETER_3D);
>  error_remove_trigger:
>  	hid_sensor_remove_trigger(indio_dev, &incl_state-
> >common_attributes);
>  	return ret;
> @@ -389,8 +389,8 @@ static void hid_incl_3d_remove(struct
> platform_device *pdev)
>  	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
>  	struct incl_3d_state *incl_state = iio_priv(indio_dev);
>  
> -	sensor_hub_remove_callback(hsdev,
> HID_USAGE_SENSOR_INCLINOMETER_3D);
>  	iio_device_unregister(indio_dev);
> +	sensor_hub_remove_callback(hsdev,
> HID_USAGE_SENSOR_INCLINOMETER_3D);
>  	hid_sensor_remove_trigger(indio_dev, &incl_state-
> >common_attributes);
>  }
>