1 files changed, 30 insertions, 27 deletions

diff --git a/runtime/class_linker.h b/runtime/class_linker.h
index a7a68b7..7750c8e 100644
--- a/runtime/class_linker.h
+++ b/runtime/class_linker.h
@@ -237,12 +237,14 @@ class ClassLinker {
   }
 
   void VisitClasses(ClassVisitor* visitor, void* arg)
-      LOCKS_EXCLUDED(dex_lock_)
+      LOCKS_EXCLUDED(Locks::classlinker_classes_lock_)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
-  // Less efficient variant of VisitClasses that doesn't hold the classlinker_classes_lock_
-  // when calling the visitor.
+
+  // Less efficient variant of VisitClasses that copies the class_table_ into secondary storage
+  // so that it can visit individual classes without holding the doesn't hold the
+  // Locks::classlinker_classes_lock_. As the Locks::classlinker_classes_lock_ isn't held this code
+  // can race with insertion and deletion of classes while the visitor is being called.
   void VisitClassesWithoutClassesLock(ClassVisitor* visitor, void* arg)
-      LOCKS_EXCLUDED(dex_lock_)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
   void VisitClassRoots(RootCallback* callback, void* arg, VisitRootFlags flags)
@@ -623,29 +625,6 @@ class ClassLinker {
                                        ConstHandle<mirror::ArtMethod> prototype)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
-  std::vector<const DexFile*> boot_class_path_;
-
-  mutable ReaderWriterMutex dex_lock_ DEFAULT_MUTEX_ACQUIRED_AFTER;
-  std::vector<size_t> new_dex_cache_roots_ GUARDED_BY(dex_lock_);;
-  std::vector<GcRoot<mirror::DexCache>> dex_caches_ GUARDED_BY(dex_lock_);
-  std::vector<const OatFile*> oat_files_ GUARDED_BY(dex_lock_);
-
-
-  // multimap from a string hash code of a class descriptor to
-  // mirror::Class* instances. Results should be compared for a matching
-  // Class::descriptor_ and Class::class_loader_.
-  typedef AllocationTrackingMultiMap<size_t, GcRoot<mirror::Class>, kAllocatorTagClassTable> Table;
-  // This contains strong roots. To enable concurrent root scanning of
-  // the class table, be careful to use a read barrier when accessing this.
-  Table class_table_ GUARDED_BY(Locks::classlinker_classes_lock_);
-  std::vector<std::pair<size_t, GcRoot<mirror::Class>>> new_class_roots_;
-
-  // Do we need to search dex caches to find image classes?
-  bool dex_cache_image_class_lookup_required_;
-  // Number of times we've searched dex caches for a class. After a certain number of misses we move
-  // the classes into the class_table_ to avoid dex cache based searches.
-  Atomic<uint32_t> failed_dex_cache_class_lookups_;
-
   mirror::Class* LookupClassFromTableLocked(const char* descriptor,
                                             const mirror::ClassLoader* class_loader,
                                             size_t hash)
@@ -656,6 +635,7 @@ class ClassLinker {
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
   void MoveImageClassesToClassTable() LOCKS_EXCLUDED(Locks::classlinker_classes_lock_)
+      LOCKS_EXCLUDED(Locks::classlinker_classes_lock_)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
   mirror::Class* LookupClassFromImage(const char* descriptor)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
@@ -672,6 +652,29 @@ class ClassLinker {
   void FixupTemporaryDeclaringClass(mirror::Class* temp_class, mirror::Class* new_class)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
+  std::vector<const DexFile*> boot_class_path_;
+
+  mutable ReaderWriterMutex dex_lock_ DEFAULT_MUTEX_ACQUIRED_AFTER;
+  std::vector<size_t> new_dex_cache_roots_ GUARDED_BY(dex_lock_);;
+  std::vector<GcRoot<mirror::DexCache>> dex_caches_ GUARDED_BY(dex_lock_);
+  std::vector<const OatFile*> oat_files_ GUARDED_BY(dex_lock_);
+
+
+  // multimap from a string hash code of a class descriptor to
+  // mirror::Class* instances. Results should be compared for a matching
+  // Class::descriptor_ and Class::class_loader_.
+  typedef AllocationTrackingMultiMap<size_t, GcRoot<mirror::Class>, kAllocatorTagClassTable> Table;
+  // This contains strong roots. To enable concurrent root scanning of
+  // the class table, be careful to use a read barrier when accessing this.
+  Table class_table_ GUARDED_BY(Locks::classlinker_classes_lock_);
+  std::vector<std::pair<size_t, GcRoot<mirror::Class>>> new_class_roots_;
+
+  // Do we need to search dex caches to find image classes?
+  bool dex_cache_image_class_lookup_required_;
+  // Number of times we've searched dex caches for a class. After a certain number of misses we move
+  // the classes into the class_table_ to avoid dex cache based searches.
+  Atomic<uint32_t> failed_dex_cache_class_lookups_;
+
   // indexes into class_roots_.
   // needs to be kept in sync with class_roots_descriptors_.
   enum ClassRoot {