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: e4a70e3e7d84 ("iio: humidity: add support to hts221 rh/temp combo device")
> Signed-off-by: Dmitry Rokosov <ddrokosov@xxxxxxxxxxxxxx>
> ---
> drivers/iio/humidity/hts221_buffer.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iio/humidity/hts221_buffer.c b/drivers/iio/humidity/hts221_buffer.c
> index f29692b9d2db..66b32413cf5e 100644
> --- a/drivers/iio/humidity/hts221_buffer.c
> +++ b/drivers/iio/humidity/hts221_buffer.c
> @@ -135,9 +135,12 @@ int hts221_allocate_trigger(struct iio_dev *iio_dev)
>
> iio_trigger_set_drvdata(hw->trig, iio_dev);
> hw->trig->ops = &hts221_trigger_ops;
> +
> + err = devm_iio_trigger_register(hw->dev, hw->trig);
> +
> iio_dev->trig = iio_trigger_get(hw->trig);
>
> - return devm_iio_trigger_register(hw->dev, hw->trig);
> + return err;
> }
>
> static int hts221_buffer_preenable(struct iio_dev *iio_dev)
> --
> 2.36.0
--
With Best Regards,
Andy Shevchenko
