kset??

ksets are the top-level container class
A bag full of identical kobjects
Part of the sysfs hierarchy glue

kobjects can exist outside of sysfs
...but ksets cannot

struct kset {
        struct subsystem *subsys;
        struct kobj_type *ktype;
        struct list_head list;
        spinlock_t list_lock;
        struct kobject kobj;
        struct kset_hotplug_ops *hotplug_ops;
};

ktype overrides the kobject's pointer