From fdfde95dec276c241108720250997fb2e9edcab3 Mon Sep 17 00:00:00 2001
From: Alexey Rybalchenko <alexryba@gmail.com>
Date: Wed, 7 Sep 2022 23:26:04 +0200
Subject: [PATCH] region example: fix race between segment reset & presence
 check

---
 examples/region/keep-alive.cxx | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/examples/region/keep-alive.cxx b/examples/region/keep-alive.cxx
index 2509295b..98234bf4 100644
--- a/examples/region/keep-alive.cxx
+++ b/examples/region/keep-alive.cxx
@@ -19,6 +19,7 @@
 #include <chrono>
 #include <csignal>
 #include <map>
+#include <mutex>
 #include <string>
 #include <thread>
 
@@ -113,6 +114,7 @@ struct ShmManager
 
     bool CheckPresence()
     {
+        std::lock_guard<std::mutex> lock(localMtx);
         for (const auto& sc : segmentCfgs) {
             if (!(fair::mq::shmem::Monitor::SegmentIsPresent(fair::mq::shmem::ShmId{shmId}, sc.id))) {
                 return false;
@@ -128,6 +130,7 @@ struct ShmManager
 
     void ResetContent()
     {
+        std::lock_guard<std::mutex> lock(localMtx);
         fair::mq::shmem::Monitor::ResetContent(fair::mq::shmem::ShmId{shmId}, segmentCfgs, regionCfgs);
     }
 
@@ -145,6 +148,7 @@ struct ShmManager
     }
 
     std::string shmId;
+    std::mutex localMtx;
     map<uint16_t, fair::mq::shmem::Segment> segments;
     map<uint16_t, unique_ptr<fair::mq::shmem::UnmanagedRegion>> regions;
     std::vector<fair::mq::shmem::SegmentConfig> segmentCfgs;