From 222af8e7e48d35d0d4dd02f4b2b0291e4e091d1c Mon Sep 17 00:00:00 2001
From: Alexander Alekhin <alexander.a.alekhin@gmail.com>
Date: Fri, 9 Apr 2021 15:46:11 +0000
Subject: [PATCH] core: avoid process cleanup deadlock if TlsStorage is not
 used

---
 modules/core/src/precomp.hpp |  2 ++
 modules/core/src/system.cpp  | 13 ++++++++++++-
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/modules/core/src/precomp.hpp b/modules/core/src/precomp.hpp
index 0ffde88..eebbda0 100644
--- a/modules/core/src/precomp.hpp
+++ b/modules/core/src/precomp.hpp
@@ -388,6 +388,8 @@ cv::Mutex& getInitializationMutex();
 #define CV_SINGLETON_LAZY_INIT(TYPE, INITIALIZER) CV_SINGLETON_LAZY_INIT_(TYPE, INITIALIZER, instance)
 #define CV_SINGLETON_LAZY_INIT_REF(TYPE, INITIALIZER) CV_SINGLETON_LAZY_INIT_(TYPE, INITIALIZER, *instance)
 
+CV_EXPORTS void releaseTlsStorageThread();
+
 int cv_snprintf(char* buf, int len, const char* fmt, ...);
 int cv_vsnprintf(char* buf, int len, const char* fmt, va_list args);
 }
diff --git a/modules/core/src/system.cpp b/modules/core/src/system.cpp
index 6e882e1..51c7363 100644
--- a/modules/core/src/system.cpp
+++ b/modules/core/src/system.cpp
@@ -1583,6 +1583,9 @@ struct ThreadData
     size_t idx;               // Thread index in TLS storage. This is not OS thread ID!
 };
 
+
+static bool g_isTlsStorageInitialized = false;
+
 // Main TLS storage class
 class TlsStorage
 {
@@ -1592,6 +1595,7 @@ public:
     {
         tlsSlots.reserve(32);
         threads.reserve(32);
+        g_isTlsStorageInitialized = true;
     }
     ~TlsStorage()
     {
@@ -1810,6 +1814,13 @@ static void WINAPI opencv_fls_destructor(void* pData)
 } // namespace details
 using namespace details;
 
+void releaseTlsStorageThread()
+{
+    if (!g_isTlsStorageInitialized)
+        return;  // nothing to release, so prefer to avoid creation of new global structures
+    getTlsStorage().releaseThread();
+}
+
 TLSDataContainer::TLSDataContainer()
 {
     key_ = (int)getTlsStorage().reserveSlot(this); // Reserve key from TLS storage
@@ -1893,7 +1904,7 @@ BOOL WINAPI DllMain(HINSTANCE, DWORD fdwReason, LPVOID lpReserved)
         {
             // Not allowed to free resources if lpReserved is non-null
             // http://msdn.microsoft.com/en-us/library/windows/desktop/ms682583.aspx
-            cv::getTlsStorage().releaseThread();
+            releaseTlsStorageThread();
         }
     }
     return TRUE;
-- 
2.7.4