From c71181ff515b2d2e464dcf769f391cd5eccc4d0f Mon Sep 17 00:00:00 2001
From: UbitUmarov <ajlduarte@sapo.pt>
Date: Tue, 12 Oct 2021 18:08:49 +0100
Subject: [PATCH] possible multithreading issues

---
 OpenSim/Framework/Monitoring/JobEngine.cs | 14 +++++++++++---
 OpenSim/Framework/ObjectJobEngine.cs      | 13 ++++++++++---
 2 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/OpenSim/Framework/Monitoring/JobEngine.cs b/OpenSim/Framework/Monitoring/JobEngine.cs
index 850e99b1a6..3f71811d36 100644
--- a/OpenSim/Framework/Monitoring/JobEngine.cs
+++ b/OpenSim/Framework/Monitoring/JobEngine.cs
@@ -188,10 +188,10 @@ namespace OpenSim.Framework.Monitoring
 
             if (m_jobQueue.Count < m_jobQueue.BoundedCapacity)
             {
-                m_jobQueue.Add(job);
-
                 lock (JobLock)
                 {
+                    m_jobQueue.Add(job);
+
                     if (m_numberThreads < m_concurrency && m_numberThreads < m_jobQueue.Count)
                     {
                         Util.FireAndForget(ProcessRequests, null, Name, false);
@@ -225,7 +225,15 @@ namespace OpenSim.Framework.Monitoring
                 try
                 {
                     if(!m_jobQueue.TryTake(out currentJob, m_timeout, m_cancelSource.Token))
-                        break;
+                    {
+                        lock (JobLock)
+                        {
+                            if (m_jobQueue.Count > 0)
+                                continue;
+                            --m_numberThreads;
+                            return;
+                        }
+                    }
                 }
                 catch
                 {
diff --git a/OpenSim/Framework/ObjectJobEngine.cs b/OpenSim/Framework/ObjectJobEngine.cs
index 1087a25a32..11027c9b34 100644
--- a/OpenSim/Framework/ObjectJobEngine.cs
+++ b/OpenSim/Framework/ObjectJobEngine.cs
@@ -141,10 +141,9 @@ namespace OpenSim.Framework
             if (!m_isRunning)
                 return false;
 
-            m_jobQueue?.Add(o);
-
             lock (m_mainLock)
             {
+                m_jobQueue?.Add(o);
                 if (m_numberThreads < m_concurrency && m_numberThreads < m_jobQueue.Count)
                 {
                     Util.FireAndForget(ProcessRequests, null, m_name, false);
@@ -162,7 +161,15 @@ namespace OpenSim.Framework
                 try
                 {
                     if(!m_jobQueue.TryTake(out obj, m_threadsHoldtime, m_cancelSource.Token))
-                        break;
+                    {
+                        lock (m_mainLock)
+                        {
+                            if (m_jobQueue.Count > 0)
+                                continue;
+                            --m_numberThreads;
+                            return;
+                        }
+                    }
                 }
                 catch
                 {