1 files changed, 13 insertions, 6 deletions
diff --git a/lib/drb/extserv.rb b/lib/drb/extserv.rb
index 7da8130c2b..af52250518 100644
--- a/lib/drb/extserv.rb
+++ b/lib/drb/extserv.rb
@@ -4,16 +4,21 @@
 =end
 
 require 'drb/drb'
+require 'monitor'
 
 module DRb
   class ExtServ
+    include MonitorMixin
     include DRbUndumped
 
     def initialize(there, name, server=nil)
+      super()
       @server = server || DRb::primary_server
       @name = name
       ro = DRbObject.new(nil, there)
-      @invoker = ro.regist(name, DRbObject.new(self, @server.uri))
+      synchronize do
+        @invoker = ro.regist(name, DRbObject.new(self, @server.uri))
+      end
     end
     attr_reader :server
 
@@ -22,11 +27,13 @@ module DRb
     end
 
     def stop_service
-      @invoker.unregist(@name)
-      server = @server
-      @server = nil
-      server.stop_service
-      true
+      synchronize do
+        @invoker.unregist(@name)
+        server = @server
+        @server = nil
+        server.stop_service
+        true
+      end
     end
 
     def alive?