--- old/src/hotspot/share/classfile/classLoaderData.cpp	2018-03-14 13:33:53.952631368 -0400
+++ new/src/hotspot/share/classfile/classLoaderData.cpp	2018-03-14 13:33:53.354576494 -0400
@@ -596,6 +596,19 @@
   return new Dictionary(this, size, resizable);
 }
 
+// Tell the GC to keep this klass alive while iterating ClassLoaderDataGraph
+void ClassLoaderData::ensure_loader_alive() {
+  // A klass that was previously considered dead can be looked up in the
+  // CLD/SD, and its _java_mirror or _class_loader can be stored in a root
+  // or a reachable object making it alive again. The SATB part of G1 needs
+  // to get notified about this potential resurrection, otherwise the marking
+  // might not find the object.
+  if (!keep_alive()) {
+    oop* o = is_anonymous() ? _klasses->java_mirror_handle().ptr_raw() : &_class_loader;
+    (void)RootAccess<ON_PHANTOM_OOP_REF>::oop_load(o);
+  }
+}
+
 // Unloading support
 oop ClassLoaderData::keep_alive_object() const {
   assert_locked_or_safepoint(_metaspace_lock);
@@ -1035,18 +1048,21 @@
 
 void ClassLoaderDataGraph::classes_do(KlassClosure* klass_closure) {
   for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
+    cld->ensure_loader_alive();
     cld->classes_do(klass_closure);
   }
 }
 
 void ClassLoaderDataGraph::classes_do(void f(Klass* const)) {
   for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
+    cld->ensure_loader_alive();
     cld->classes_do(f);
   }
 }
 
 void ClassLoaderDataGraph::methods_do(void f(Method*)) {
   for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
+    cld->ensure_loader_alive();
     cld->methods_do(f);
   }
 }
@@ -1054,6 +1070,7 @@
 void ClassLoaderDataGraph::modules_do(void f(ModuleEntry*)) {
   assert_locked_or_safepoint(Module_lock);
   for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
+    cld->ensure_loader_alive();
     cld->modules_do(f);
   }
 }
@@ -1071,6 +1088,7 @@
 void ClassLoaderDataGraph::packages_do(void f(PackageEntry*)) {
   assert_locked_or_safepoint(Module_lock);
   for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
+    cld->ensure_loader_alive();
     cld->packages_do(f);
   }
 }
@@ -1087,6 +1105,7 @@
 
 void ClassLoaderDataGraph::loaded_classes_do(KlassClosure* klass_closure) {
   for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
+    cld->ensure_loader_alive();
     cld->loaded_classes_do(klass_closure);
   }
 }
@@ -1108,6 +1127,7 @@
 // Only walks the classes defined in this class loader.
 void ClassLoaderDataGraph::dictionary_classes_do(void f(InstanceKlass*)) {
   FOR_ALL_DICTIONARY(cld) {
+    cld->ensure_loader_alive();
     cld->dictionary()->classes_do(f);
   }
 }
@@ -1115,6 +1135,7 @@
 // Only walks the classes defined in this class loader.
 void ClassLoaderDataGraph::dictionary_classes_do(void f(InstanceKlass*, TRAPS), TRAPS) {
   FOR_ALL_DICTIONARY(cld) {
+    cld->ensure_loader_alive();
     cld->dictionary()->classes_do(f, CHECK);
   }
 }
@@ -1122,12 +1143,14 @@
 // Walks all entries in the dictionary including entries initiated by this class loader.
 void ClassLoaderDataGraph::dictionary_all_entries_do(void f(InstanceKlass*, ClassLoaderData*)) {
   FOR_ALL_DICTIONARY(cld) {
+    cld->ensure_loader_alive();
     cld->dictionary()->all_entries_do(f);
   }
 }
 
 void ClassLoaderDataGraph::verify_dictionary() {
   FOR_ALL_DICTIONARY(cld) {
+    cld->ensure_loader_alive();
     cld->dictionary()->verify();
   }
 }
--- old/src/hotspot/share/classfile/classLoaderData.hpp	2018-03-14 13:33:54.683698447 -0400
+++ new/src/hotspot/share/classfile/classLoaderData.hpp	2018-03-14 13:33:54.087643756 -0400
@@ -292,6 +292,7 @@
 
   void unload();
   bool keep_alive() const       { return _keep_alive > 0; }
+  void ensure_loader_alive();
   void classes_do(void f(Klass*));
   void loaded_classes_do(KlassClosure* klass_closure);
   void classes_do(void f(InstanceKlass*));
--- old/src/hotspot/share/prims/jvmtiGetLoadedClasses.cpp	2018-03-14 13:33:55.376762038 -0400
+++ new/src/hotspot/share/prims/jvmtiGetLoadedClasses.cpp	2018-03-14 13:33:54.778707164 -0400
@@ -42,20 +42,6 @@
   JvmtiEnv* _env;
   Thread*   _cur_thread;
 
-// Tell the GC to keep this klass alive
-static void ensure_klass_alive(oop o) {
-  // A klass that was previously considered dead can be looked up in the
-  // CLD/SD, and its _java_mirror or _class_loader can be stored in a root
-  // or a reachable object making it alive again. The SATB part of G1 needs
-  // to get notified about this potential resurrection, otherwise the marking
-  // might not find the object.
-#if INCLUDE_ALL_GCS
-  if (UseG1GC && o != NULL) {
-    G1BarrierSet::enqueue(o);
-  }
-#endif
-}
-
 public:
   LoadedClassesClosure(Thread* thread, JvmtiEnv* env) : _cur_thread(thread), _env(env) {
     assert(_cur_thread == Thread::current(), "must be current thread");
@@ -64,7 +50,6 @@
   void do_klass(Klass* k) {
     // Collect all jclasses
     _classStack.push((jclass) _env->jni_reference(Handle(_cur_thread, k->java_mirror())));
-    ensure_klass_alive(k->java_mirror());
   }
 
   int extract(jclass* result_list) {