Linux Security Module security_operations

I try to register the Linux Security module, Root_Plug ( The source of LSM kernel module source is from http://lxr.linux.no/source/security/root_plug.c#L105 )
But it returns me '-EINVAL'

So I went to check the code, and I think this is what giving me the trouble

Code:

---

int register_security(struct security_operations *ops)
83 {
84        if (verify(ops)) {
85                printk(KERN_DEBUG "%s could not verify "
86                        "security_operations structure.\n", __FUNCTION__);
87                return -EINVAL;
88        }
89
90        if (security_ops != &dummy_security_ops)
91                return -EAGAIN;
92
93        security_ops = ops;
94
95        return 0;
96 }

---

at the line 84, the vertify brings to "return -EINVAL;"

Does anybody know what is the situation here?? am I wrong with this or?
I really have no clue...
please help.
Thanks...