[PATCH v2] iio: temperature: hid-sensor-temperature: switch to non-devm iio_device_register()

[Sanjay Chitroda]

From: Sanjay Chitroda <sanjayembeddedse@xxxxxxxxx>

Avoid using devm_iio_device_register(), as this driver requires explicit
error handling and teardown ordering.

With devm_iio_device_register(), IIO device remains registered until the
devres cleanup phase. However, driver's remove() callback removes the
sensor hub callback and trigger support. This can create a race window
where IIO device is still visible and read_raw() requests are issued.
These requests might call sensor_hub_input_attr_get_raw_value(), which
waits up to 5 seconds for a response from the sensor hub callback that
has already been removed.

Add an explicit iio_device_unregister() call in the teardown path to
ensure deterministic cleanup, so that userspace can no longer access the
device once backend resources begin to be dismantled.

Fixes: 59d0f2da3569 ("iio: hid: Add temperature sensor support")
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Maxwell Doose <m32285159@xxxxxxxxx>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxx>
Signed-off-by: Sanjay Chitroda <sanjayembeddedse@xxxxxxxxx>

---
Changes in v2:
- Added review tags of Maxwell and Andy along with stable Cc
- Based on input from Srinivas and investigation use-after-free
  explanation was not sufficiently justified so updated the commit
  message with appropriate information and kept Fixes tag
- Link to v1: https://lore.kernel.org/all/20260622052135.1804135-1-sanjayembedded@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 a8d3a15f9c53..ab6ec8f659b8 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);
 }
-- 
--