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
@@ -2181,11 +2181,6 @@
 	bcopy(&src->cr_startcopy, &dest->cr_startcopy,
 	    (unsigned)((caddr_t)&src->cr_endcopy -
 		(caddr_t)&src->cr_startcopy));
-	/*
-	 * Avoid an assertion in crsetgroups() -> crextend().  To be removed as
-	 * 'cr_ngroups' is moved out of the bcopied area.
-	 */
-	dest->cr_ngroups = 0;
 	dest->cr_flags = src->cr_flags;
 	crsetgroups(dest, src->cr_ngroups, src->cr_groups);
 	uihold(dest->cr_uidinfo);
diff --git a/sys/sys/ucred.h b/sys/sys/ucred.h
--- a/sys/sys/ucred.h
+++ b/sys/sys/ucred.h
@@ -72,20 +72,22 @@
 	u_int	cr_users;		/* (c) proc + thread using this cred */
 	u_int	cr_flags;		/* credential flags */
 	struct auditinfo_addr	cr_audit;	/* Audit properties. */
-#define	cr_startcopy cr_uid
+#define	cr_startcopy cr_ispare
+	u_int	cr_ispare;		/* spare integer */
+	gid_t	cr_rgid;		/* real group id */
+	gid_t	cr_svgid;		/* saved group id */
 	uid_t	cr_uid;			/* effective user id */
 	uid_t	cr_ruid;		/* real user id */
 	uid_t	cr_svuid;		/* saved user id */
-	int	cr_ngroups;		/* number of groups */
-	gid_t	cr_rgid;		/* real group id */
-	gid_t	cr_svgid;		/* saved group id */
 	struct uidinfo	*cr_uidinfo;	/* per euid resource consumption */
 	struct uidinfo	*cr_ruidinfo;	/* per ruid resource consumption */
 	struct prison	*cr_prison;	/* jail(2) */
 	struct loginclass	*cr_loginclass; /* login class */
-	void 		*cr_pspare2[2];	/* general use 2 */
+	void		*cr_pspare[1];	/* spare pointer */
 #define	cr_endcopy	cr_label
 	struct label	*cr_label;	/* MAC label */
+	u_int	cr_ispare2;		/* spare integer */
+	int	cr_ngroups;		/* number of groups */
 	gid_t	*cr_groups;		/* groups */
 	int	cr_agroups;		/* Available groups */
 	/* storage for small groups */