diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c
--- a/sys/kern/vfs_subr.c
+++ b/sys/kern/vfs_subr.c
@@ -99,6 +99,10 @@
 #include <vm/vm_kern.h>
 #include <vm/uma.h>
 
+#if defined(DEBUG_VFS_LOCKS) && (!defined(INVARIANTS) || !defined(WITNESS))
+#error DEBUG_VFS_LOCKS requires INVARIANTS and WITNESS
+#endif
+
 #ifdef DDB
 #include <ddb/ddb.h>
 #endif