[PATCH v2 3/3] iio: humidity: hid-sensor-humidity: Use per-instance callbacks

[Christopher Hoover <ch@murgatroid.com>]

hid-sensor-humidity keeps a single static struct
hid_sensor_hub_callbacks for all instances and overwrites its pdev in
every probe, so with two humidity sensors, input reports for one are
delivered with the other's platform device, and a NULL dereference
follows once that device is removed.  The same bug was found in
hid-sensor-temperature, which shares this code.

Keep the callbacks in struct hid_humidity_state, as the other HID
sensor drivers (accel, gyro, als, ...) do.

Fixes: d7ed89d5aadf ("iio: hid: Add humidity sensor support")
Cc: stable@vger.kernel.org
Signed-off-by: Christopher Hoover <ch@murgatroid.com>
---
 drivers/iio/humidity/hid-sensor-humidity.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/iio/humidity/hid-sensor-humidity.c b/drivers/iio/humidity/hid-sensor-humidity.c
index 7cec81ff5685..95ee1d71c1a7 100644
--- a/drivers/iio/humidity/hid-sensor-humidity.c
+++ b/drivers/iio/humidity/hid-sensor-humidity.c
@@ -14,6 +14,7 @@
 
 struct hid_humidity_state {
 	struct hid_sensor_common common_attributes;
+	struct hid_sensor_hub_callbacks callbacks;
 	struct hid_sensor_hub_attribute_info humidity_attr;
 	struct {
 		s32 humidity_data;
@@ -184,11 +185,6 @@ static int humidity_parse_report(struct platform_device *pdev,
 	return ret;
 }
 
-static struct hid_sensor_hub_callbacks humidity_callbacks = {
-	.send_event = &humidity_proc_event,
-	.capture_sample = &humidity_capture_sample,
-};
-
 /* Function to initialize the processing for usage id */
 static int hid_humidity_probe(struct platform_device *pdev)
 {
@@ -240,9 +236,11 @@ static int hid_humidity_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, indio_dev);
 
-	humidity_callbacks.pdev = pdev;
+	humid_st->callbacks.send_event = humidity_proc_event;
+	humid_st->callbacks.capture_sample = humidity_capture_sample;
+	humid_st->callbacks.pdev = pdev;
 	ret = sensor_hub_register_callback(hsdev, HID_USAGE_SENSOR_HUMIDITY,
-					   &humidity_callbacks);
+					   &humid_st->callbacks);
 	if (ret)
 		goto error_remove_trigger;
 
-- 
2.43.0