iio:chemical:ccs811: rearrange iio trigger get and register

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: f1f065d7ac30 ("iio: chemical: ccs811: Add support for data ready trigger")
Signed-off-by: Dmitry Rokosov <ddrokosov@sberdevices.ru>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220524181150.9240-5-ddrokosov@sberdevices.ru
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/chemical/ccs811.c b/drivers/iio/chemical/ccs811.c
index 847194f..80ef1aa 100644 (file)
--- a/drivers/iio/chemical/ccs811.c
+++ b/drivers/iio/chemical/ccs811.c
@@ -499,11 +499,11 @@ static int ccs811_probe(struct i2c_client *client,
 
                data->drdy_trig->ops = &ccs811_trigger_ops;
                iio_trigger_set_drvdata(data->drdy_trig, indio_dev);
-               indio_dev->trig = data->drdy_trig;
-               iio_trigger_get(indio_dev->trig);
                ret = iio_trigger_register(data->drdy_trig);
                if (ret)
                        goto err_poweroff;
+
+               indio_dev->trig = iio_trigger_get(data->drdy_trig);
        }
 
        ret = iio_triggered_buffer_setup(indio_dev, NULL,