Fix dead lock in isolate shutdown.

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/become.h"
 #include "vm/code_observers.h"
 #include "vm/cpu.h"
 #include "vm/dart_api_state.h"
@@ skipping 292 matching lines @@
   if (FLAG_support_service) {
     Service::SetGetServiceAssetsCallback(get_service_assets);
   }
 
   ServiceIsolate::Run();
 
   return NULL;
 }
 
 
+// This waits until only the VM isolate and the service isolate remains in the
+// list, i.e. list length == 2.
+void Dart::WaitForApplicationIsolateShutdown() {
+  ASSERT(!Isolate::creation_enabled_);
+  MonitorLocker ml(Isolate::isolates_list_monitor_);
+  while ((Isolate::isolates_list_head_ != NULL) &&
+         (Isolate::isolates_list_head_->next_ != NULL) &&
+         (Isolate::isolates_list_head_->next_->next_ != NULL)) {
+    ml.Wait();
+  }
+  ASSERT(Isolate::isolates_list_head_ == Dart::vm_isolate());

[zra, 2016/06/10 21:51:07]

Is the VM isolate really guaranteed to be first?

[Florian Schneider, 2016/06/10 21:53:05]

good point. I have to fix this assertion.

+  ASSERT(ServiceIsolate::IsServiceIsolate(Isolate::isolates_list_head_->next_));
+}
+
+
 // This waits until only the VM isolate remains in the list.
 void Dart::WaitForIsolateShutdown() {
   ASSERT(!Isolate::creation_enabled_);
   MonitorLocker ml(Isolate::isolates_list_monitor_);
   while ((Isolate::isolates_list_head_ != NULL) &&
          (Isolate::isolates_list_head_->next_ != NULL)) {
     ml.Wait();
   }
   ASSERT(Isolate::isolates_list_head_ == Dart::vm_isolate());
 }
@@ skipping 41 matching lines @@
     }
     Isolate::DisableIsolateCreation();
 
     // Send the OOB Kill message to all remaining application isolates.
     if (FLAG_trace_shutdown) {
       OS::PrintErr("[+%" Pd64 "ms] SHUTDOWN: Killing all app isolates\n",
                    timestamp());
     }
     Isolate::KillAllIsolates(Isolate::kInternalKillMsg);
 
+    // Wait for all isolates, but the service and the vm isolate to shut down.
+    if (FLAG_trace_shutdown) {
+      OS::PrintErr("[+%" Pd64 "ms] SHUTDOWN: Shutting down app isolates\n",
+                   timestamp());
+    }
+    WaitForApplicationIsolateShutdown();
+
     // Shutdown the service isolate.
     if (FLAG_trace_shutdown) {
       OS::PrintErr("[+%" Pd64 "ms] SHUTDOWN: Shutting down service isolate\n",
                    timestamp());
     }
     ServiceIsolate::Shutdown();
 
-    // Wait for all application isolates and the service isolate to shutdown
+    // Wait for the remaining isolate (service isolate) to shutdown
     // before shutting down the thread pool.
     if (FLAG_trace_shutdown) {
       OS::PrintErr("[+%" Pd64 "ms] SHUTDOWN: Waiting for isolate shutdown\n",
                    timestamp());
     }
     WaitForIsolateShutdown();
 
     // Shutdown the thread pool. On return, all thread pool threads have exited.
     if (FLAG_trace_shutdown) {
       OS::PrintErr("[+%" Pd64 "ms] SHUTDOWN: Deleting thread pool\n",
@@ skipping 313 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