iio:accel:mxc4005: rearrange iio trigger get and register

BugLink: https://bugs.launchpad.net/bugs/1986718
commit 9354c224c9b4f55847a0de3e968cba2ebf15af3b 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: 47196620c82f ("iio: mxc4005: add data ready trigger for mxc4005")
Signed-off-by: Dmitry Rokosov <ddrokosov@sberdevices.ru>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220524181150.9240-4-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>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

diff --git a/drivers/iio/accel/mxc4005.c b/drivers/iio/accel/mxc4005.c
index b3afbf064915268839c747a7defac132f8fac841..df600d2917c0ad56250922ef4bc431989bf28796 100644 (file)
--- a/drivers/iio/accel/mxc4005.c
+++ b/drivers/iio/accel/mxc4005.c
@@ -456,8 +456,6 @@ static int mxc4005_probe(struct i2c_client *client,
 
                data->dready_trig->ops = &mxc4005_trigger_ops;
                iio_trigger_set_drvdata(data->dready_trig, indio_dev);
-               indio_dev->trig = data->dready_trig;
-               iio_trigger_get(indio_dev->trig);
                ret = devm_iio_trigger_register(&client->dev,
                                                data->dready_trig);
                if (ret) {
@@ -465,6 +463,8 @@ static int mxc4005_probe(struct i2c_client *client,
                                "failed to register trigger\n");
                        return ret;
                }
+
+               indio_dev->trig = iio_trigger_get(data->dready_trig);
        }
 
        return devm_iio_device_register(&client->dev, indio_dev);