[PATCH 4.9 13/29] iio:accel:bma180: rearrange iio trigger get and register

[Greg Kroah-Hartman]

From: Dmitry Rokosov <DDRokosov@xxxxxxxxxxxxxx>

commit e5f3205b04d7f95a2ef43bce4b454a7f264d6923 upstream.

IIO trigger interface function iio_trigger_get() should be called after
iio_trigger_register() (or its devm analogue) strictly, because of
iio_trigger_get() acquires module refcnt based on the trigger->owner
pointer, which is initialized inside iio_trigger_register() to
THIS_MODULE.
If this call order is wrong, the next iio_trigger_put() (from sysfs
callback or "delete module" path) will dereference "default" module
refcnt, which is incorrect behaviour.

Fixes: 0668a4e4d297 ("iio: accel: bma180: Fix indio_dev->trig assignment")
Signed-off-by: Dmitry Rokosov <ddrokosov@xxxxxxxxxxxxxx>
Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
Link: https://lore.kernel.org/r/20220524181150.9240-2-ddrokosov@xxxxxxxxxxxxxx
Cc: <Stable@xxxxxxxxxxxxxxx>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/iio/accel/bma180.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/iio/accel/bma180.c
+++ b/drivers/iio/accel/bma180.c
@@ -776,11 +776,12 @@ static int bma180_probe(struct i2c_clien
 		data->trig->dev.parent = &client->dev;
 		data->trig->ops = &bma180_trigger_ops;
 		iio_trigger_set_drvdata(data->trig, indio_dev);
-		indio_dev->trig = iio_trigger_get(data->trig);
 
 		ret = iio_trigger_register(data->trig);
 		if (ret)
 			goto err_trigger_free;
+
+		indio_dev->trig = iio_trigger_get(data->trig);
 	}
 
 	ret = iio_triggered_buffer_setup(indio_dev, NULL,