Careful reference counting

kobject reference counting may not be enough
Must also cover objects required by the kobject

Example: char devices

struct kobject *cdev_get(struct cdev *p)
{
        struct module *owner = p->owner;
        struct kobject *kobj;

        if (owner && !try_module_get(owner))
                return NULL;
        kobj = kobject_get(&p->kobj);
        if (!kobj)
                module_put(owner);
        return kobj;
}