diff --git a/sys/vm/vm_page.c b/sys/vm/vm_page.c
index 91683a648ebb..561a5d8b58d4 100644
--- a/sys/vm/vm_page.c
+++ b/sys/vm/vm_page.c
@@ -335,6 +335,7 @@ void
 vm_page_io_start(vm_page_t m)
 {
 
+	VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED);
 	mtx_assert(&vm_page_queue_mtx, MA_OWNED);
 	m->busy++;
 }
@@ -343,6 +344,7 @@ void
 vm_page_io_finish(vm_page_t m)
 {
 
+	VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED);
 	mtx_assert(&vm_page_queue_mtx, MA_OWNED);
 	m->busy--;
 	if (m->busy == 0)