From 9e32306daea5578ac5cff1424678da25e2a158af Mon Sep 17 00:00:00 2001
From: David Faure <david.faure@kdab.com>
Date: Sat, 29 Mar 2025 09:36:36 +0100
Subject: [PATCH] QTestLib: fix race on QElapsedTimers from WatchDog thread

The WatchDog thread calls printTestRunTime() which reads the two
timers, created and started in the main thread.

Pick-to: 6.9 6.8 6.5
Change-Id: I1a337648fddf87190075b7902311544d0ab21ac3
Reviewed-by: Marc Mutz <marc.mutz@qt.io>
---
 src/testlib/qtestlog.cpp | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/src/testlib/qtestlog.cpp b/src/testlib/qtestlog.cpp
index 2bde5a94eca..3938c9a85f8 100644
--- a/src/testlib/qtestlog.cpp
+++ b/src/testlib/qtestlog.cpp
@@ -69,6 +69,7 @@ static void saveCoverageTool(const char * appname, bool testfailed, bool install
 #endif
 }
 
+Q_CONSTINIT static QBasicMutex elapsedTimersMutex; // due to the WatchDog thread
 Q_CONSTINIT static QElapsedTimer elapsedFunctionTime;
 Q_CONSTINIT static QElapsedTimer elapsedTotalTime;
 
@@ -320,7 +321,10 @@ namespace QTest {
 
 void QTestLog::enterTestFunction(const char* function)
 {
-    elapsedFunctionTime.start();
+    {
+        QMutexLocker locker(&elapsedTimersMutex);
+        elapsedFunctionTime.start();
+    }
     if (printAvailableTags)
         return;
 
@@ -548,8 +552,11 @@ void QTestLog::addBenchmarkResults(const QList<QBenchmarkResult> &results)
 
 void QTestLog::startLogging()
 {
-    elapsedTotalTime.start();
-    elapsedFunctionTime.start();
+    {
+        QMutexLocker locker(&elapsedTimersMutex);
+        elapsedTotalTime.start();
+        elapsedFunctionTime.start();
+    }
     for (auto &logger : QTest::loggers->allLoggers())
         logger->startLogging();
     QTest::oldMessageHandler = qInstallMessageHandler(QTest::messageHandler);
@@ -767,11 +774,13 @@ bool QTestLog::installedTestCoverage()
 
 qint64 QTestLog::nsecsTotalTime()
 {
+    QMutexLocker locker(&elapsedTimersMutex);
     return elapsedTotalTime.nsecsElapsed();
 }
 
 qint64 QTestLog::nsecsFunctionTime()
 {
+    QMutexLocker locker(&elapsedTimersMutex);
     return elapsedFunctionTime.nsecsElapsed();
 }