From 590eb9504d56ca026a4a315e6c28ce7d46b2b8bd Mon Sep 17 00:00:00 2001
From: Stefan Boberg <stefan@boberg.org>
Date: Tue, 24 Feb 2026 11:31:07 +0100
Subject: fix m_AsyncWorkPool threading issue

---
 src/zenhttp/servers/httpsys.cpp | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

(limited to 'src/zenhttp/servers/httpsys.cpp')

diff --git a/src/zenhttp/servers/httpsys.cpp b/src/zenhttp/servers/httpsys.cpp
index 020b9d134..c44549a5a 100644
--- a/src/zenhttp/servers/httpsys.cpp
+++ b/src/zenhttp/servers/httpsys.cpp
@@ -26,6 +26,7 @@
 #	include <zencore/workthreadpool.h>
 #	include "iothreadpool.h"
 
+#	include <atomic>
 #	include <http.h>
 #	include <asio.hpp>	 // for resolving addresses for GetExternalHost
 
@@ -132,8 +133,8 @@ private:
 
 	std::unique_ptr<WinIoThreadPool> m_IoThreadPool;
 
-	RwLock			  m_AsyncWorkPoolInitLock;
-	WorkerThreadPool* m_AsyncWorkPool = nullptr;
+	RwLock						   m_AsyncWorkPoolInitLock;
+	std::atomic<WorkerThreadPool*> m_AsyncWorkPool = nullptr;
 
 	std::vector<std::wstring> m_BaseUris;  // eg: http://*:nnnn/
 	HTTP_SERVER_SESSION_ID	  m_HttpSessionId	   = 0;
@@ -1035,8 +1036,8 @@ HttpSysServer::~HttpSysServer()
 		ZEN_ERROR("~HttpSysServer() called without calling Close() first");
 	}
 
-	delete m_AsyncWorkPool;
-	m_AsyncWorkPool = nullptr;
+	delete m_AsyncWorkPool.load(std::memory_order_relaxed);
+	m_AsyncWorkPool.store(nullptr, std::memory_order_relaxed);
 }
 
 void
@@ -1326,17 +1327,17 @@ HttpSysServer::WorkPool()
 {
 	ZEN_MEMSCOPE(GetHttpsysTag());
 
-	if (!m_AsyncWorkPool)
+	if (!m_AsyncWorkPool.load(std::memory_order_acquire))
 	{
 		RwLock::ExclusiveLockScope _(m_AsyncWorkPoolInitLock);
 
-		if (!m_AsyncWorkPool)
+		if (!m_AsyncWorkPool.load(std::memory_order_relaxed))
 		{
-			m_AsyncWorkPool = new WorkerThreadPool(m_InitialConfig.AsyncWorkThreadCount, "http_async");
+			m_AsyncWorkPool.store(new WorkerThreadPool(m_InitialConfig.AsyncWorkThreadCount, "http_async"), std::memory_order_release);
 		}
 	}
 
-	return *m_AsyncWorkPool;
+	return *m_AsyncWorkPool.load(std::memory_order_relaxed);
 }
 
 void
-- 
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