Re: [PATCH v2 3/5] iio:accel:mxc4005: rearrange iio trigger get and register

[Andy Shevchenko]

On Tue, May 24, 2022 at 8:14 PM Dmitry Rokosov <DDRokosov@xxxxxxxxxxxxxx> wrote:
>
> 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.

Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>

> Fixes: 47196620c82f ("iio: mxc4005: add data ready trigger for mxc4005")
> Signed-off-by: Dmitry Rokosov <ddrokosov@xxxxxxxxxxxxxx>
> ---
>  drivers/iio/accel/mxc4005.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iio/accel/mxc4005.c b/drivers/iio/accel/mxc4005.c
> index b3afbf064915..df600d2917c0 100644
> --- 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);
> --
> 2.36.0



-- 
With Best Regards,
Andy Shevchenko