[PATCH v2 1/5] iio:accel:bma180: rearrange iio trigger get and register

From: Dmitry Rokosov
Date: Tue May 24 2022 - 14:15:14 EST


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>
---
drivers/iio/accel/bma180.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/accel/bma180.c b/drivers/iio/accel/bma180.c
index d8a454c266d5..5d0bd0fc3018 100644
--- a/drivers/iio/accel/bma180.c
+++ b/drivers/iio/accel/bma180.c
@@ -1006,11 +1006,12 @@ static int bma180_probe(struct i2c_client *client,

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,
--
2.36.0