Index: sys/kern/kern_cpuset.c
===================================================================
--- sys/kern/kern_cpuset.c
+++ sys/kern/kern_cpuset.c
@@ -160,6 +160,11 @@
 cpuset_getroot(struct cpuset *set)
 {
 
+	/*
+	 * If it's a jail, get the parent's root
+	 */
+	if ((set->cs_flags & CPU_SET_ROOT) == 1 && set->cs_parent != NULL)
+		set = set->cs_parent;
 	while ((set->cs_flags & CPU_SET_ROOT) == 0 && set->cs_parent != NULL)
 		set = set->cs_parent;
 	return (set);