reference: with td->td_ucred, it will be desirable to authorize
based on td->td_ucred, rather than p->p_ucred.
o Since the same variable 'p' was later used with pfind() on the target
process for the wakeup, introduce a new local variable 'targetp'
to use instead.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, NAI Labs