diff -r b02fb6a07ed5 -r 0e3d6188f198 src/share/vm/runtime/mutexLocker.hpp
--- a/src/share/vm/runtime/mutexLocker.hpp	Tue Sep 03 06:41:37 2019 +0100
+++ b/src/share/vm/runtime/mutexLocker.hpp	Tue Sep 03 06:57:35 2019 +0100
@@ -141,6 +141,7 @@
 extern Mutex*   Management_lock;                 // a lock used to serialize JVM management
 extern Monitor* Service_lock;                    // a lock used for service thread operation
 extern Monitor* PeriodicTask_lock;               // protects the periodic task structure
+extern Monitor* RedefineClasses_lock;            // locks classes from parallel redefinition
 
 #ifdef INCLUDE_TRACE
 extern Mutex*   JfrStacktrace_lock;              // used to guard access to the JFR stacktrace table