Index: head/sys/vm/vm_page.c
===================================================================
--- head/sys/vm/vm_page.c
+++ head/sys/vm/vm_page.c
@@ -757,6 +757,7 @@
 {
 	u_int x;
 
+	vm_page_lock_assert(m, MA_NOTOWNED);
 	vm_page_assert_sbusied(m);
 
 	for (;;) {