--- a/hotspot/src/share/vm/runtime/thread.hpp	Tue Dec 08 05:50:46 2015 -0800
+++ b/hotspot/src/share/vm/runtime/thread.hpp	Tue Dec 08 20:04:03 2015 +0100
@@ -272,7 +272,7 @@
   jlong _allocated_bytes;                       // Cumulative number of bytes allocated on
                                                 // the Java heap
 
-  TRACE_DATA _trace_data;                       // Thread-local data for tracing
+  mutable TRACE_DATA _trace_data;               // Thread-local data for tracing
 
   ThreadExt _ext;