Index: sys/vm/uma_core.c
===================================================================
--- sys/vm/uma_core.c
+++ sys/vm/uma_core.c
@@ -1918,8 +1918,9 @@
 	/*
 	 * We only destroy kegs from non secondary zones.
 	 */
-	if ((keg = zone->uz_keg) != NULL &&
+	if ((zone->uz_lockptr != &zone->uz_lock) &&
 	    (zone->uz_flags & UMA_ZONE_SECONDARY) == 0)  {
+		keg = zone->uz_keg;
 		rw_wlock(&uma_rwlock);
 		LIST_REMOVE(keg, uk_link);
 		rw_wunlock(&uma_rwlock);