diff -r 2c3cc4b01880 -r c16ac7a2eba4 src/hotspot/share/jfr/writers/jfrStorageAdapter.hpp
--- a/src/hotspot/share/jfr/writers/jfrStorageAdapter.hpp	Wed Oct 30 16:14:56 2019 +0100
+++ b/src/hotspot/share/jfr/writers/jfrStorageAdapter.hpp	Wed Oct 30 19:43:52 2019 +0100
@@ -82,7 +82,7 @@
     assert(_thread != NULL, "invariant");
     Flush f(_storage, used, requested, _thread);
     _storage = f.result();
-    return _storage != NULL;
+    return _storage != NULL && !_storage->excluded();
   }
 
   void release() {
@@ -236,7 +236,8 @@
   void release() {}
   bool flush(size_t used, size_t requested) {
     // don't flush/expand a buffer that is not our own
-    return false;
+    _pos = _start;
+    return true;
   }
 };