Re: [PATCH v2 4/5] iio:chemical:ccs811: 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: f1f065d7ac30 ("iio: chemical: ccs811: Add support for data ready trigger")
> Signed-off-by: Dmitry Rokosov <ddrokosov@xxxxxxxxxxxxxx>
> ---
>  drivers/iio/chemical/ccs811.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iio/chemical/ccs811.c b/drivers/iio/chemical/ccs811.c
> index 847194fa1e46..80ef1aa9aae3 100644
> --- 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,
> --
> 2.36.0



-- 
With Best Regards,
Andy Shevchenko