--- a/src/hotspot/share/jfr/recorder/checkpoint/jfrCheckpointManager.cpp	Tue May 21 13:06:52 2019 -0400
+++ b/src/hotspot/share/jfr/recorder/checkpoint/jfrCheckpointManager.cpp	Tue May 21 20:53:27 2019 +0200
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2016, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -136,6 +136,8 @@
 
 void JfrCheckpointManager::register_full(BufferPtr t, Thread* thread) {
   // nothing here at the moment
+  assert(t != NULL, "invariant");
+  assert(t->acquired_by(thread), "invariant");
   assert(t->retired(), "invariant");
 }