1 files changed, 26 insertions, 1 deletions
diff --git a/tests/auto/corelib/thread/qthreadpool/tst_qthreadpool.cpp b/tests/auto/corelib/thread/qthreadpool/tst_qthreadpool.cpp
index cd245030db..e85fb5ea88 100644
--- a/tests/auto/corelib/thread/qthreadpool/tst_qthreadpool.cpp
+++ b/tests/auto/corelib/thread/qthreadpool/tst_qthreadpool.cpp
@@ -104,6 +104,7 @@ private slots:
     void stressTest();
     void takeAllAndIncreaseMaxThreadCount();
     void waitForDoneAfterTake();
+    void threadReuse();
 
 private:
     QMutex m_functionTestMutex;
@@ -803,7 +804,7 @@ void tst_QThreadPool::tryStartPeakThreadCount()
     CounterTask task;
     QThreadPool threadPool;
 
-    for (int i = 0; i < 20; ++i) {
+    for (int i = 0; i < 4*QThread::idealThreadCount(); ++i) {
         if (threadPool.tryStart(&task) == false)
             QTest::qWait(10);
     }
@@ -1385,5 +1386,29 @@ void tst_QThreadPool::waitForDoneAfterTake()
 
 }
 
+/*
+    Try trigger reuse of expired threads and check that all tasks execute.
+
+    This is a regression test for QTBUG-72872.
+*/
+void tst_QThreadPool::threadReuse()
+{
+    QThreadPool manager;
+    manager.setExpiryTimeout(-1);
+    manager.setMaxThreadCount(1);
+
+    constexpr int repeatCount = 10000;
+    constexpr int timeoutMs = 1000;
+    QSemaphore sem;
+
+    for (int i = 0; i < repeatCount; i++) {
+        manager.start([&sem]() { sem.release(); });
+        manager.start([&sem]() { sem.release(); });
+        manager.releaseThread();
+        QVERIFY(sem.tryAcquire(2, timeoutMs));
+        manager.reserveThread();
+    }
+}
+
 QTEST_MAIN(tst_QThreadPool);
 #include "tst_qthreadpool.moc"