From 81a7a4c2d94fca6fc595dcb147831b9585eaee5f Mon Sep 17 00:00:00 2001
From: Thiago Macieira <thiago.macieira@intel.com>
Date: Mon, 24 Mar 2025 17:07:07 -0700
Subject: [PATCH] QThreadStorage: ensure global static exists when finish() is
 called
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

For the thread that calls ::exit() (usually, the main thread).
Otherwise, depending on construction order, it is possible for the
QThreadStorage's destructor list to have been destroyed by the time
destroy_current_thread_data() → QThreadData::finish() calls our
finish().

Fixes: QTBUG-135044
Pick-to: 6.9 6.8
Change-Id: Ic5a10367ff31e7faa039fffdc2067eba9642fbf9
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
---
 src/corelib/CMakeLists.txt            |  2 +-
 src/corelib/thread/qthread_p.h        | 17 ++++++++--------
 src/corelib/thread/qthread_unix.cpp   |  1 +
 src/corelib/thread/qthread_win.cpp    |  1 +
 src/corelib/thread/qthreadstorage.cpp |  8 ++++++++
 src/corelib/thread/qthreadstorage_p.h | 29 +++++++++++++++++++++++++++
 6 files changed, 49 insertions(+), 9 deletions(-)
 create mode 100644 src/corelib/thread/qthreadstorage_p.h

diff --git a/src/corelib/CMakeLists.txt b/src/corelib/CMakeLists.txt
index 23cafd2be17..38cca5a9682 100644
--- a/src/corelib/CMakeLists.txt
+++ b/src/corelib/CMakeLists.txt
@@ -748,7 +748,7 @@ qt_internal_extend_target(Core CONDITION QT_FEATURE_thread
         thread/qreadwritelock.cpp thread/qreadwritelock_p.h
         thread/qsemaphore.cpp thread/qsemaphore.h
         thread/qthreadpool.cpp thread/qthreadpool.h thread/qthreadpool_p.h
-        thread/qthreadstorage.cpp
+        thread/qthreadstorage.cpp thread/qthreadstorage_p.h
 )
 
 qt_internal_extend_target(Core CONDITION QT_FEATURE_thread AND UNIX
diff --git a/src/corelib/thread/qthread_p.h b/src/corelib/thread/qthread_p.h
index 35c5d7c7c76..b34336d7e16 100644
--- a/src/corelib/thread/qthread_p.h
+++ b/src/corelib/thread/qthread_p.h
@@ -17,18 +17,19 @@
 //
 //
 
-#include "qplatformdefs.h"
 #include "QtCore/qthread.h"
-#include "QtCore/qmutex.h"
-#include "QtCore/qstack.h"
-#if QT_CONFIG(thread)
-#include "QtCore/qwaitcondition.h"
-#endif
-#include "QtCore/qmap.h"
+
 #include "QtCore/qcoreapplication.h"
 #include "private/qobject_p.h"
+#include "QtCore/qmap.h"
+#include "QtCore/qmutex.h"
+#include "QtCore/qstack.h"
+
+#if QT_CONFIG(thread)
+#include "private/qthreadstorage_p.h"
+#include "QtCore/qwaitcondition.h"
+#endif
 
-#include <algorithm>
 #include <atomic>
 
 QT_BEGIN_NAMESPACE
diff --git a/src/corelib/thread/qthread_unix.cpp b/src/corelib/thread/qthread_unix.cpp
index c19390e16b5..1710aecb8d6 100644
--- a/src/corelib/thread/qthread_unix.cpp
+++ b/src/corelib/thread/qthread_unix.cpp
@@ -223,6 +223,7 @@ struct QThreadDataDestroyer
     }
 
     struct EarlyMainThread {
+        EarlyMainThread() { QThreadStoragePrivate::init(); }
         ~EarlyMainThread()
         {
             // running function-local destructors upon ::exit()
diff --git a/src/corelib/thread/qthread_win.cpp b/src/corelib/thread/qthread_win.cpp
index 77868b13a04..746231b359e 100644
--- a/src/corelib/thread/qthread_win.cpp
+++ b/src/corelib/thread/qthread_win.cpp
@@ -82,6 +82,7 @@ static void set_thread_data(QThreadData *data) noexcept
 {
     if (data) {
         struct Cleanup {
+            Cleanup() { QThreadStoragePrivate::init(); }
             ~Cleanup() { destroy_current_thread_data(currentThreadData); }
         };
         static thread_local Cleanup currentThreadCleanup;
diff --git a/src/corelib/thread/qthreadstorage.cpp b/src/corelib/thread/qthreadstorage.cpp
index 0deff1b19d9..d7f4b560a53 100644
--- a/src/corelib/thread/qthreadstorage.cpp
+++ b/src/corelib/thread/qthreadstorage.cpp
@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
 #include "qthreadstorage.h"
+#include "qthreadstorage_p.h"
 
 #include "private/qcoreapplication_p.h"
 #include "qthread.h"
@@ -133,6 +134,13 @@ void **QThreadStorageData::set(void *p)
     return &value;
 }
 
+void QThreadStoragePrivate::init()
+{
+    // Make sure the Q_GLOBAL_STATIC is initialized, ensuring consistent
+    // destruction order.
+    destructors();
+}
+
 void QThreadStorageData::finish(void **p)
 {
     QList<void *> *tls = reinterpret_cast<QList<void *> *>(p);
diff --git a/src/corelib/thread/qthreadstorage_p.h b/src/corelib/thread/qthreadstorage_p.h
new file mode 100644
index 00000000000..d73b5a1d8e5
--- /dev/null
+++ b/src/corelib/thread/qthreadstorage_p.h
@@ -0,0 +1,29 @@
+// Copyright (C) 2025 Intel Corporation.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#ifndef QTHREADSTORAGE_P_H
+#define QTHREADSTORAGE_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <qlist.h>
+#include <private/qglobal_p.h>
+
+QT_BEGIN_NAMESPACE
+
+namespace QThreadStoragePrivate {
+void init();
+} // namespace QThreadStoragePrivate
+
+QT_END_NAMESPACE
+
+#endif // QTHREADSTORAGE_P_H