* Increasing ScenePresences locking to prevent race conditions such as those seen in one of the crashes of mantis 1163

* It's not impossible that this could lead to deadlock where sessions simply appear to freeze, even though the region console still responds.
* If this is the case, please file a mantis

OpenSim/Region/Environment/Scenes/InnerScene.cs

@@ -115,8 +115,12 @@ namespace OpenSim.Region.Environment.Scenes
         }
 
         public void Close()
+        {
+            lock (ScenePresences)
             {
                 ScenePresences.Clear();
+            }
+            
             //SceneObjects.Clear();
             Entities.Clear();
         }
@@ -792,6 +796,8 @@ namespace OpenSim.Region.Environment.Scenes
         /// <returns></returns>
         public List<ScenePresence> GetScenePresences(FilterAvatarList filter)
         {
+            // No locking of scene presences here since we're passing back a list...
+            
             List<ScenePresence> result = new List<ScenePresence>();
             List<ScenePresence> ScenePresencesList = GetScenePresences();
 
@@ -812,11 +818,14 @@ namespace OpenSim.Region.Environment.Scenes
         /// <param name="avatarID"></param>
         /// <returns>null if the agent was not found</returns>
         public ScenePresence GetScenePresence(LLUUID agentID)
+        {
+            lock (ScenePresences)
             {
                 if (ScenePresences.ContainsKey(agentID))
                 {
                     return ScenePresences[agentID];
                 }
+            }
             
             return null;
         }
@@ -916,6 +925,8 @@ namespace OpenSim.Region.Environment.Scenes
         }
 
         internal bool TryGetAvatarByName(string avatarName, out ScenePresence avatar)
+        {
+            lock (ScenePresences)
             {
                 foreach (ScenePresence presence in ScenePresences.Values)
                 {
@@ -930,6 +941,7 @@ namespace OpenSim.Region.Environment.Scenes
                         }
                     }
                 }
+            }
 
             avatar = null;
             return false;
@@ -1007,12 +1019,15 @@ namespace OpenSim.Region.Environment.Scenes
         }
 
         internal void ForEachClient(Action<IClientAPI> action)
+        {
+            lock (ScenePresences)
             {
                 foreach (ScenePresence presence in ScenePresences.Values)
                 {
                     action(presence.ControllingClient);
                 }
             }
+        }
 
         #endregion
 

OpenSim/Region/Environment/Scenes/Scene.cs

@@ -2075,6 +2075,8 @@ namespace OpenSim.Region.Environment.Scenes
         public virtual void AgentCrossing(ulong regionHandle, LLUUID agentID, LLVector3 position, bool isFlying)
         {
             if (regionHandle == m_regInfo.RegionHandle)
+            {
+                lock (m_scenePresences)
                 {
                     if (m_scenePresences.ContainsKey(agentID))
                     {
@@ -2091,6 +2093,7 @@ namespace OpenSim.Region.Environment.Scenes
                     }
                 }
             }
+        }
 
         public virtual bool IncomingChildAgentDataUpdate(ulong regionHandle, ChildAgentDataUpdate cAgentData)
         {
@@ -2202,6 +2205,8 @@ namespace OpenSim.Region.Environment.Scenes
         /// <param name="flags"></param>
         public void RequestTeleportLocation(IClientAPI remoteClient, ulong regionHandle, LLVector3 position,
                                             LLVector3 lookAt, uint flags)
+        {
+            lock (m_scenePresences)
             {
                 if (m_scenePresences.ContainsKey(remoteClient.AgentId))
                 {
@@ -2209,6 +2214,7 @@ namespace OpenSim.Region.Environment.Scenes
                                                                  position, lookAt, flags);
                 }
             }
+        }
 
         /// <summary>
         /// Tries to teleport agent to landmark.
@@ -2217,6 +2223,8 @@ namespace OpenSim.Region.Environment.Scenes
         /// <param name="regionHandle"></param>
         /// <param name="position"></param>
         public void RequestTeleportLandmark(IClientAPI remoteClient, ulong regionHandle, LLVector3 position)
+        {
+            lock (m_scenePresences)
             {
                 if (m_scenePresences.ContainsKey(remoteClient.AgentId))
                 {
@@ -2224,6 +2232,7 @@ namespace OpenSim.Region.Environment.Scenes
                                                                  position, LLVector3.Zero, 0);
                 }
             }
+        }
 
         /// <summary>
         /// Agent is crossing the border into a neighbouring region.  Tell the neighbour about it!
@@ -2352,6 +2361,8 @@ namespace OpenSim.Region.Environment.Scenes
         /// <param name="url"></param>
         public void SendUrlToUser(LLUUID avatarID, string objectName, LLUUID objectID, LLUUID ownerID, bool groupOwned,
                                   string message, string url)
+        {
+            lock (m_scenePresences)
             {
                 if (m_scenePresences.ContainsKey(avatarID))
                 {
@@ -2359,12 +2370,17 @@ namespace OpenSim.Region.Environment.Scenes
                                                                              message, url);
                 }
             }
+        }
 
         public void SendDialogToUser(LLUUID avatarID, string objectName, LLUUID objectID, LLUUID ownerID, string message, LLUUID TextureID, int ch, string[] buttonlabels)
+        {
+            lock (m_scenePresences)
             {
                 if (m_scenePresences.ContainsKey(avatarID))
                 {
-                m_scenePresences[avatarID].ControllingClient.SendDialog(objectName, objectID, ownerID, message, TextureID, ch, buttonlabels);
+                    m_scenePresences[avatarID].ControllingClient.SendDialog(
+                        objectName, objectID, ownerID, message, TextureID, ch, buttonlabels);
+                }
             }
         }
 
@@ -2477,12 +2493,15 @@ namespace OpenSim.Region.Environment.Scenes
         /// <param name="message"></param>
         /// <param name="modal"></param>
         public void SendAlertToUser(LLUUID agentID, string message, bool modal)
+        {
+            lock (m_scenePresences)
             {
                 if (m_scenePresences.ContainsKey(agentID))
                 {
                     m_scenePresences[agentID].ControllingClient.SendAgentAlertMessage(message, modal);
                 }
             }
+        }
 
         /// <summary>
         /// 
@@ -2494,11 +2513,13 @@ namespace OpenSim.Region.Environment.Scenes
         public void handleRequestGodlikePowers(LLUUID agentID, LLUUID sessionID, LLUUID token, bool godLike,
                                                IClientAPI controllingClient)
         {
-            // First check that this is the sim owner
+            lock (m_scenePresences)
-            if (Permissions.GenericEstatePermission(agentID))
             {
                 // User needs to be logged into this sim
                 if (m_scenePresences.ContainsKey(agentID))
+                {   
+                    // First check that this is the sim owner
+                    if (Permissions.GenericEstatePermission(agentID))
                     {
                         // Next we check for spoofing.....
                         LLUUID testSessionID = m_scenePresences[agentID].ControllingClient.SessionId;
@@ -2511,12 +2532,13 @@ namespace OpenSim.Region.Environment.Scenes
                             }
                         }
                     }
-            }
                     else
                     {
                         m_scenePresences[agentID].ControllingClient.SendAgentAlertMessage("Request for god powers denied", false);
                     }
                 }
+            }
+        }
 
         /// <summary>
         /// Sends a Big Blue Box message on the upper right of the screen to the client
@@ -2571,6 +2593,8 @@ namespace OpenSim.Region.Environment.Scenes
         {
             // For some reason the client sends this seemingly hard coded UUID for kicking everyone.   Dun-know.
             LLUUID kickUserID = new LLUUID("44e87126e7944ded05b37c42da3d5cdb");
+            lock (m_scenePresences)
+            {
                 if (m_scenePresences.ContainsKey(agentID) || agentID == kickUserID)
                 {
                     if (Permissions.GenericEstatePermission(godID))
@@ -2586,6 +2610,7 @@ namespace OpenSim.Region.Environment.Scenes
 
                                                         }
                                 );
+                            
                             // This is a bit crude.   It seems the client will be null before it actually stops the thread
                             // The thread will kill itself eventually :/
                             // Is there another way to make sure *all* clients get this 'inter region' message?
@@ -2623,6 +2648,7 @@ namespace OpenSim.Region.Environment.Scenes
                     }
                 }
             }
+        }
 
         public void HandleObjectPermissionsUpdate(IClientAPI controller, LLUUID agentID, LLUUID sessionID, byte field, uint localId, uint mask, byte set)
         {

OpenSim/Region/Environment/Scenes/ScenePresence.cs

@@ -1506,6 +1506,7 @@ namespace OpenSim.Region.Environment.Scenes
             foreach (ScenePresence avatar in avatars)
             {
                 SendFullUpdateToOtherClient(avatar);
+                
                 if (avatar.LocalId != LocalId)
                 {
                     if (!avatar.m_isChildAgent || m_scene.m_seeIntoRegionFromNeighbor)