8275800: Redefinition leaks MethodData::_extra_data_lock

src/hotspot/share/oops/instanceKlass.cpp

@@ -583,7 +583,10 @@ void InstanceKlass::deallocate_contents(ClassLoaderData* loader_data) {
 
   // Release C heap allocated data that this points to, which includes
   // reference counting symbol names.
-  release_C_heap_structures_internal();
+  // Can't release the constant pool here because the constant pool can be
+  // deallocated separately from the InstanceKlass for default methods and
+  // redefine classes.
+  release_C_heap_structures(/* release_constant_pool */ false);
 
   deallocate_methods(loader_data, methods());
   set_methods(NULL);
@@ -1638,7 +1641,8 @@ bool InstanceKlass::find_field_from_offset(int offset, bool is_static, fieldDesc
 void InstanceKlass::methods_do(void f(Method* method)) {
   // Methods aren't stable until they are loaded.  This can be read outside
   // a lock through the ClassLoaderData for profiling
-  if (!is_loaded()) {
+  // Redefined scratch classes are on the list and need to be cleaned
+  if (!is_loaded() && !is_scratch_class()) {
     return;
   }
 
@@ -2681,22 +2685,13 @@ static void method_release_C_heap_structures(Method* m) {
   m->release_C_heap_structures();
 }
 
-void InstanceKlass::release_C_heap_structures() {
-
+// Called also by InstanceKlass::deallocate_contents, with false for release_constant_pool.
+void InstanceKlass::release_C_heap_structures(bool release_constant_pool) {
   // Clean up C heap
-  release_C_heap_structures_internal();
-  constants()->release_C_heap_structures();
+  Klass::release_C_heap_structures();
 
   // Deallocate and call destructors for MDO mutexes
   methods_do(method_release_C_heap_structures);
-}
-
-void InstanceKlass::release_C_heap_structures_internal() {
-  Klass::release_C_heap_structures();
-
-  // Can't release the constant pool here because the constant pool can be
-  // deallocated separately from the InstanceKlass for default methods and
-  // redefine classes.
 
   // Deallocate oop map cache
   if (_oop_map_cache != NULL) {
@@ -2732,6 +2727,10 @@ void InstanceKlass::release_C_heap_structures_internal() {
 #endif
 
   FREE_C_HEAP_ARRAY(char, _source_debug_extension);
+
+  if (release_constant_pool) {
+    constants()->release_C_heap_structures();
+  }
 }
 
 void InstanceKlass::set_source_debug_extension(const char* array, int length) {
@@ -3988,8 +3987,6 @@ void InstanceKlass::purge_previous_version_list() {
       // so will be deallocated during the next phase of class unloading.
       log_trace(redefine, class, iklass, purge)
         ("previous version " INTPTR_FORMAT " is dead.", p2i(pv_node));
-      // For debugging purposes.
-      pv_node->set_is_scratch_class();
       // Unlink from previous version list.
       assert(pv_node->class_loader_data() == loader_data, "wrong loader_data");
       InstanceKlass* next = pv_node->previous_versions();
@@ -4104,8 +4101,6 @@ void InstanceKlass::add_previous_version(InstanceKlass* scratch_class,
   ConstantPool* cp_ref = scratch_class->constants();
   if (!cp_ref->on_stack()) {
     log_trace(redefine, class, iklass, add)("scratch class not added; no methods are running");
-    // For debugging purposes.
-    scratch_class->set_is_scratch_class();
     scratch_class->class_loader_data()->add_to_deallocate_list(scratch_class);
     return;
   }

src/hotspot/share/oops/instanceKlass.hpp

@@ -1101,7 +1101,7 @@ class InstanceKlass: public Klass {
   // callbacks for actions during class unloading
   static void unload_class(InstanceKlass* ik);
 
-  virtual void release_C_heap_structures();
+  virtual void release_C_heap_structures(bool release_constant_pool = true);
 
   // Naming
   const char* signature_name() const;
@@ -1218,9 +1218,6 @@ class InstanceKlass: public Klass {
                                   StaticLookupMode static_mode,
                                   PrivateLookupMode private_mode);
 
-  // Free CHeap allocated fields.
-  void release_C_heap_structures_internal();
-
 #if INCLUDE_JVMTI
   // RedefineClasses support
   void link_previous_versions(InstanceKlass* pv) { _previous_versions = pv; }

src/hotspot/share/oops/klass.cpp

@@ -105,7 +105,7 @@ bool Klass::is_subclass_of(const Klass* k) const {
   return false;
 }
 
-void Klass::release_C_heap_structures() {
+void Klass::release_C_heap_structures(bool release_constant_pool) {
   if (_name != NULL) _name->decrement_refcount();
 }
 

src/hotspot/share/oops/klass.hpp

@@ -661,7 +661,7 @@ class Klass : public Metadata {
   Symbol* name() const                   { return _name; }
   void set_name(Symbol* n);
 
-  virtual void release_C_heap_structures();
+  virtual void release_C_heap_structures(bool release_constant_pool = true);
 
  public:
   virtual jint compute_modifier_flags() const = 0;

src/hotspot/share/prims/jvmtiRedefineClasses.cpp

@@ -4404,6 +4404,9 @@ void VM_RedefineClasses::redefine_single_class(Thread* current, jclass the_jclas
 
   the_class->set_has_been_redefined();
 
+  // Scratch class is unloaded but still needs cleaning, and skipping for CDS.
+  scratch_class->set_is_scratch_class();
+
   // keep track of previous versions of this class
   the_class->add_previous_version(scratch_class, emcp_method_count);