[PATCH 5.4 39/60] iio:accel:bma180: rearrange iio trigger get and register

Greg Kroah-Hartman
2022-06-27T11:34:13Z

From: Dmitry Rokosov <DDRokosov@sberdevices.ru>

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@sberdevices.ru>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220524181150.9240-2-ddrokosov@sberdevices.ru
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
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
@@ -793,11 +793,12 @@ 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,