From 572747a3f92186ce7f5f08c38aaa89382d3f20d9 Mon Sep 17 00:00:00 2001
From: Jon Evans <jon@craftyjon.com>
Date: Sun, 21 Nov 2021 13:30:36 -0500
Subject: [PATCH] Protect KIID generator from threading

---
 common/kiid.cpp | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/common/kiid.cpp b/common/kiid.cpp
index 07c21b2d24..16806551bd 100644
--- a/common/kiid.cpp
+++ b/common/kiid.cpp
@@ -33,8 +33,12 @@
 #include <boost/uuid/entropy_error.hpp>
 #endif
 
+#include <mutex>
+
 #include <wx/log.h>
 
+// boost:mt19937 is not thread-safe
+static std::mutex rng_mutex;
 
 // Create only once, as seeding is *very* expensive
 static boost::mt19937 rng;
@@ -69,9 +73,14 @@ KIID::KIID()
 #endif
 
         if( createNilUuids )
+        {
             m_uuid = nilGenerator();
+        }
         else
+        {
+            std::lock_guard<std::mutex> lock( rng_mutex );
             m_uuid = randomGenerator();
+        }
 
 #if BOOST_VERSION >= 106700
     }