commit d889178ec78930538d9d6a66c3df9ee9afaffbb4
author Mathieu Chartier <mathieuc@google.com> Sun Mar 02 13:28:37 2014 -0800
committer Mathieu Chartier <mathieuc@google.com> Mon Mar 03 17:08:30 2014 -0800
tree 6fa250bdadcdfc1702f57500e618b51df6d46828
parent 06c09f6d79e037ee00113d6289ef98226680797d

Guard entrypoint changing by runtime shutdown lock.

There was a race when we changed the allocation entrypoints where a
new thread would be starting (Thread::Init) and initialize to the
wrong entrypoints. Guarding allocation entrypoint changing
with the runtime shutdown lock fixes this race condition since
Thread::Init is only called with the runtime shutdown lock held.

Bug: 13250963

Change-Id: I8eb209c124b6bf17020de874e1b0083f158b8200

runtime/gc/heap.h

diff --git a/runtime/gc/heap.h b/runtime/gc/heap.h
index b194d8d..88adf81 100644
--- a/runtime/gc/heap.h
+++ b/runtime/gc/heap.h
@@ -197,13 +197,16 @@
   void RegisterNativeFree(JNIEnv* env, int bytes);
 
   // Change the allocator, updates entrypoints.
-  void ChangeAllocator(AllocatorType allocator);
+  void ChangeAllocator(AllocatorType allocator)
+      EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_)
+      LOCKS_EXCLUDED(Locks::runtime_shutdown_lock_);
 
   // Transition the garbage collector during runtime, may copy objects from one space to another.
   void TransitionCollector(CollectorType collector_type);
 
   // Change the collector to be one of the possible options (MS, CMS, SS).
-  void ChangeCollector(CollectorType collector_type);
+  void ChangeCollector(CollectorType collector_type)
+      EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_);
 
   // The given reference is believed to be to an object in the Java heap, check the soundness of it.
   // TODO: NO_THREAD_SAFETY_ANALYSIS since we call this everywhere and it is impossible to find a
@@ -465,7 +468,8 @@
 
   // Revoke all the thread-local allocation stacks.
   void RevokeAllThreadLocalAllocationStacks(Thread* self)
-      EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_);
+      EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_)
+      LOCKS_EXCLUDED(Locks::runtime_shutdown_lock_, Locks::thread_list_lock_);
 
   // Mark all the objects in the allocation stack in the specified bitmap.
   void MarkAllocStack(accounting::SpaceBitmap* bitmap1, accounting::SpaceBitmap* bitmap2,