6770608: G1: Mutator thread can flush barrier and satb queues during safepoint 6660573: G1: BigApps Failure : guarantee(satb_mq_set.completed_buffers_num() == 0,"invariant") Summary: When exiting a mutator thread is removed from the thread list before it has a chance to flush its SATB and barrier queues. If GC happens at this moment the objects that are refererred from these queues can be moved, which will case a crash. The fix is simply to flush the buffers before removing a thread from the list. Reviewed-by: jcoomes, tonyp

--- a/src/share/vm/gc_implementation/g1/ptrQueue.hpp	Fri Nov 07 12:52:16 2008 -0800
+++ b/src/share/vm/gc_implementation/g1/ptrQueue.hpp	Fri Nov 14 14:23:05 2008 -0800
@@ -62,7 +62,9 @@
   // given PtrQueueSet.
   PtrQueue(PtrQueueSet*, bool perm = false);
   // Release any contained resources.
-  ~PtrQueue();
+  void flush();
+  // Calls flush() when destroyed.
+  ~PtrQueue() { flush(); }
 
   // Associate a lock with a ptr queue.
   void set_lock(Mutex* lock) { _lock = lock; }