From 87488f13387adb52e6430972c5de165e41d4db75 Mon Sep 17 00:00:00 2001
From: Sergey Grigoryants <isergey.am@gmail.com>
Date: Tue, 8 Sep 2020 19:31:58 +0300
Subject: [PATCH] Fix data race in GetInstance

---
 src/Singleton/Conceptual/ThreadSafe/main.cc | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/src/Singleton/Conceptual/ThreadSafe/main.cc b/src/Singleton/Conceptual/ThreadSafe/main.cc
index 1307cd4..c0b5a1f 100644
--- a/src/Singleton/Conceptual/ThreadSafe/main.cc
+++ b/src/Singleton/Conceptual/ThreadSafe/main.cc
@@ -112,13 +112,10 @@ std::mutex Singleton::mutex_;
      */
 Singleton *Singleton::GetInstance(const std::string& value)
 {
+    std::lock_guard<std::mutex> lock(mutex_);
     if (pinstance_ == nullptr)
     {
-        std::lock_guard<std::mutex> lock(mutex_);
-        if (pinstance_ == nullptr)
-        {
-            pinstance_ = new Singleton(value);
-        }
+        pinstance_ = new Singleton(value);
     }
     return pinstance_;
 }