Index: head/sys/vm/vm_map.c
===================================================================
--- head/sys/vm/vm_map.c
+++ head/sys/vm/vm_map.c
@@ -1965,6 +1965,14 @@
 
 	vm_map_lock(map);
 
+	/*
+	 * Ensure that we are not concurrently wiring pages.  vm_map_wire() may
+	 * need to fault pages into the map and will drop the map lock while
+	 * doing so, and the VM object may end up in an inconsistent state if we
+	 * update the protection on the map entry in between faults.
+	 */
+	vm_map_wait_busy(map);
+
 	VM_MAP_RANGE_CHECK(map, start, end);
 
 	if (vm_map_lookup_entry(map, start, &entry)) {