--- old/src/hotspot/share/classfile/classLoaderData.hpp	2017-10-12 12:04:59.318680496 -0400
+++ new/src/hotspot/share/classfile/classLoaderData.hpp	2017-10-12 12:04:58.945312561 -0400
@@ -194,7 +194,7 @@
       Chunk(Chunk* c) : _next(c), _size(0) { }
     };
 
-    Chunk* _head;
+    Chunk* volatile _head;
 
     void oops_do_chunk(OopClosure* f, Chunk* c, const juint size);