Add an XXX comment noting that getrusage() accesses p_stats->p_ru

and p_stats->p_cru without holding the appropriate locks.

sys/kern/kern_resource.c

@@ -806,6 +806,7 @@ getrusage(td, uap)
 	}
 	mtx_unlock(&Giant);
 	if (error == 0) {
+		/* XXX Unlocked access to p_stats->p_ru or p_cru. */
 		error = copyout(rup, uap->rusage, sizeof (struct rusage));
 	}
 	return(error);