diff -r 1c21c60f51bf -r 6a0c42c40cd1 src/hotspot/share/classfile/classLoaderData.hpp
--- a/src/hotspot/share/classfile/classLoaderData.hpp	Mon Oct 16 20:22:41 2017 +0000
+++ b/src/hotspot/share/classfile/classLoaderData.hpp	Mon Oct 16 22:36:06 2017 -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);