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
