Inconsistent locking of SenseRepeaters in Script Engine.

When I attempt to 'save oar' on a region with thousands of scripts with timers, I get a NullReferenceException every time. The problem comes from inconsistent locking in SensorRepeat.cs of the SenseRepeaters List. It is iterated and modified in many places and these places are all wrapped in a lock except in the GetSerializationData(). This is the function throwing the exception because an item in the list becomes null during iteration.

The attached patch locks SenseRepeatListLock in GetSerializationData()

1 files changed, 11 insertions, 8 deletions

diff --git a/OpenSim/Region/ScriptEngine/Shared/Api/Implementation/Plugins/SensorRepeat.cs b/OpenSim/Region/ScriptEngine/Shared/Api/Implementation/Plugins/SensorRepeat.cs
index ee01c3c..b75a2e4 100644
--- a/OpenSim/Region/ScriptEngine/Shared/Api/Implementation/Plugins/SensorRepeat.cs
+++ b/OpenSim/Region/ScriptEngine/Shared/Api/Implementation/Plugins/SensorRepeat.cs
@@ -516,16 +516,19 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api.Plugins
         {
             List<Object> data = new List<Object>();
 
-            foreach (SenseRepeatClass ts in SenseRepeaters)
+            lock (SenseRepeatListLock)
             {
-                if (ts.itemID == itemID)
+                foreach (SenseRepeatClass ts in SenseRepeaters)
                 {
-                    data.Add(ts.interval);
-                    data.Add(ts.name);
-                    data.Add(ts.keyID);
-                    data.Add(ts.type);
-                    data.Add(ts.range);
-                    data.Add(ts.arc);
+                    if (ts.itemID == itemID)
+                    {
+                        data.Add(ts.interval);
+                        data.Add(ts.name);
+                        data.Add(ts.keyID);
+                        data.Add(ts.type);
+                        data.Add(ts.range);
+                        data.Add(ts.arc);
+                    }
                 }
             }
             return data.ToArray();