diff --git a/sys/kern/kern_prot.c b/sys/kern/kern_prot.c
--- a/sys/kern/kern_prot.c
+++ b/sys/kern/kern_prot.c
@@ -93,6 +93,10 @@
 static void crsetgroups_locked(struct ucred *cr, int ngrp,
     gid_t *groups);
 
+static int cr_canseeotheruids(struct ucred *u1, struct ucred *u2);
+static int cr_canseeothergids(struct ucred *u1, struct ucred *u2);
+static int cr_canseejailproc(struct ucred *u1, struct ucred *u2);
+
 #ifndef _SYS_SYSPROTO_H_
 struct getpid_args {
 	int	dummy;
@@ -1346,7 +1350,7 @@
  * References: *u1 and *u2 must not change during the call
  *             u1 may equal u2, in which case only one reference is required
  */
-int
+static int
 cr_canseeotheruids(struct ucred *u1, struct ucred *u2)
 {
 
@@ -1376,7 +1380,7 @@
  * References: *u1 and *u2 must not change during the call
  *             u1 may equal u2, in which case only one reference is required
  */
-int
+static int
 cr_canseeothergids(struct ucred *u1, struct ucred *u2)
 {
 	int i, match;
@@ -1418,7 +1422,7 @@
  * References: *u1 and *u2 must not change during the call
  *             u1 may equal u2, in which case only one reference is required
  */
-int
+static int
 cr_canseejailproc(struct ucred *u1, struct ucred *u2)
 {
 	return ((see_jail_proc != 0 || u1->cr_prison == u2->cr_prison ||
diff --git a/sys/sys/proc.h b/sys/sys/proc.h
--- a/sys/sys/proc.h
+++ b/sys/sys/proc.h
@@ -1160,9 +1160,6 @@
 int	cr_bsd_visibility(struct ucred *u1, struct ucred *u2);
 int	cr_cansee(struct ucred *u1, struct ucred *u2);
 int	cr_canseesocket(struct ucred *cred, struct socket *so);
-int	cr_canseeothergids(struct ucred *u1, struct ucred *u2);
-int	cr_canseeotheruids(struct ucred *u1, struct ucred *u2);
-int	cr_canseejailproc(struct ucred *u1, struct ucred *u2);
 int	cr_cansignal(struct ucred *cred, struct proc *proc, int signum);
 int	enterpgrp(struct proc *p, pid_t pgid, struct pgrp *pgrp,
 	    struct session *sess);