diff --git a/sys/vm/vm_map.h b/sys/vm/vm_map.h
index c1d10c93c3c..daf2b6ea4ca 100644
--- a/sys/vm/vm_map.h
+++ b/sys/vm/vm_map.h
@@ -71,6 +71,8 @@
 #ifndef	_VM_MAP_
 #define	_VM_MAP_
 
+#include <sys/lockmgr.h>
+
 /*
  *	Types defined:
  *