On Mon, 2021-02-22 at 18:31 +0900, Daejun Park wrote: > +} > +static DEVICE_ATTR_RW(requeue_timeout_ms); > + > +static struct attribute *hpb_dev_param_attrs[] = { > + &dev_attr_requeue_timeout_ms.attr, > +}; here, you lost a NULL member at the end of attribute struct. Bean