Fixes for OSThread creation shutdown race.

runtime/vm/dart.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/dart.h"
 
 #include "vm/code_observers.h"
 #include "vm/cpu.h"
 #include "vm/dart_api_state.h"
 #include "vm/dart_entry.h"
@@ skipping 230 matching lines @@
     // Send the OOB Kill message to all remaining application isolates.
     Isolate::KillAllIsolates(Isolate::kInternalKillMsg);
 
     // Shutdown the service isolate.
     ServiceIsolate::Shutdown();
 
     // Wait for all application isolates and the service isolate to shutdown
     // before shutting down the thread pool.
     WaitForIsolateShutdown();
 
-    // Disable creation of any new OSThread structures which means no more new
-    // threads can do an EnterIsolate. This must come after isolate shutdown
-    // because new threads may need to be spawned to shutdown the isolates.
-    OSThread::DisableOSThreadCreation();
-
     // Shutdown the thread pool. On return, all thread pool threads have exited.
     delete thread_pool_;
     thread_pool_ = NULL;
 
+    // Disable creation of any new OSThread structures which means no more new
+    // threads can do an EnterIsolate. This must come after isolate shutdown
+    // because new threads may need to be spawned to shutdown the isolates.
+    // This must come after deletion of the thread pool to avoid a race in which
+    // a thread spawned by the thread pool does not exit through the thread
+    // pool, messing up its bookkeeping.
+    OSThread::DisableOSThreadCreation();
+
     // Set the VM isolate as current isolate.
     bool result = Thread::EnterIsolate(vm_isolate_);
     ASSERT(result);
 
     ShutdownIsolate();
     vm_isolate_ = NULL;
     ASSERT(Isolate::IsolateListLength() == 0);
 
     TargetCPUFeatures::Cleanup();
     StoreBuffer::ShutDown();
@@ skipping 182 matching lines @@
   return predefined_handles_->handles_.IsValidScopedHandle(address);
 }
 
 
 bool Dart::IsReadOnlyApiHandle(Dart_Handle handle) {
   ASSERT(predefined_handles_ != NULL);
   return predefined_handles_->api_handles_.IsValidHandle(handle);
 }
 
 }  // namespace dart