Lock the heartbeat against multiple invocations. May prevent deadlocks and/or

runaway thread use

OpenSim/Region/Framework/Scenes/Scene.cs

@@ -137,6 +137,8 @@ namespace OpenSim.Region.Framework.Scenes
         protected IAssetService m_AssetService = null;
         protected IAuthorizationService m_AuthorizationService = null;
 
+        private Object m_heartbeatLock = new Object();
+
         public IAssetService AssetService
         {
             get
@@ -942,6 +944,9 @@ namespace OpenSim.Region.Framework.Scenes
         /// <param name="e"></param>
         private void Heartbeat(object sender)
         {
+            if (!Monitor.TryEnter(m_heartbeatLock))
+                return;
+
             try
             {
                 Update();
@@ -952,6 +957,11 @@ namespace OpenSim.Region.Framework.Scenes
             catch (ThreadAbortException)
             {
             }
+            finally
+            {
+                Monitor.Pulse(m_heartbeatLock);
+                Monitor.Exit(m_heartbeatLock);
+            }
         }
 
         /// <summary>