From 9c28eec5ad722cb46db840ae636bcc9343d29d70 Mon Sep 17 00:00:00 2001
From: Olivier Goffart <olivier.goffart@nokia.com>
Date: Thu, 4 Nov 2010 13:37:48 +0100
Subject: [PATCH] QThreadStorage: fix memory leak if thread storage are added while destroying

The destructor(q) function could use itself and create new QThreadStorage.
This might be the case for example, when using qDebug in a destructor.

Task-number: QTBUG-14579
Reveiwed-by: pending
---
 src/corelib/thread/qthreadstorage.cpp            |   10 ++-
 tests/auto/qthreadstorage/tst_qthreadstorage.cpp |   72 ++++++++++++++++++++++
 2 files changed, 79 insertions(+), 3 deletions(-)

diff --git a/src/corelib/thread/qthreadstorage.cpp b/src/corelib/thread/qthreadstorage.cpp
index 2fc04f5..ef0e009 100644
--- a/src/corelib/thread/qthreadstorage.cpp
+++ b/src/corelib/thread/qthreadstorage.cpp
@@ -177,12 +177,16 @@ void QThreadStorageData::finish(void **p)
     if (!tls || tls->isEmpty() || !mutex())
         return; // nothing to do
 
-    DEBUG_MSG("QThreadStorageData: Destroying storage for thread %p", QThread::currentThread());
+    bool restart;
 
-    for(int i = tls->size() - 1; i >= 0; i--) {
-        void *&value = (*tls)[i];
+    DEBUG_MSG("QThreadStorageData: Destroying storage for thread %p", QThread::currentThread());
+    restart = false;
+    while (!tls->isEmpty()) {
+        void *&value = tls->last();
         void *q = value;
         value = 0;
+        int i = tls->size() - 1;
+        tls->resize(i);
 
         if (!q) {
             // data already deleted
diff --git a/tests/auto/qthreadstorage/tst_qthreadstorage.cpp b/tests/auto/qthreadstorage/tst_qthreadstorage.cpp
index ed86165..54f8bd9 100644
--- a/tests/auto/qthreadstorage/tst_qthreadstorage.cpp
+++ b/tests/auto/qthreadstorage/tst_qthreadstorage.cpp
@@ -77,6 +77,7 @@ private slots:
     void adoptedThreads();
     void ensureCleanupOrder();
     void QTBUG13877_crashOnExit();
+    void QTBUG14579_leakInDestructor();
 };
 
 class Pointer
@@ -310,5 +311,76 @@ void tst_QThreadStorage::QTBUG13877_crashOnExit()
     QVERIFY(process.exitStatus() != QProcess::CrashExit);
 }
 
+// S stands for thread Safe.
+class SPointer
+{
+public:
+    static QBasicAtomicInt count;
+    inline SPointer() { count.ref(); }
+    inline ~SPointer() { count.deref(); }
+};
+QBasicAtomicInt SPointer::count = Q_BASIC_ATOMIC_INITIALIZER(0);
+
+Q_GLOBAL_STATIC(QThreadStorage<SPointer *>, QTBUG14579_pointers1)
+Q_GLOBAL_STATIC(QThreadStorage<SPointer *>, QTBUG14579_pointers2)
+
+class QTBUG14579_class
+{
+public:
+    SPointer member;
+    inline ~QTBUG14579_class() {
+        QVERIFY(!QTBUG14579_pointers1()->hasLocalData());
+        QVERIFY(!QTBUG14579_pointers2()->hasLocalData());
+        QTBUG14579_pointers2()->setLocalData(new SPointer);
+        QTBUG14579_pointers1()->setLocalData(new SPointer);
+        QVERIFY(QTBUG14579_pointers1()->hasLocalData());
+        QVERIFY(QTBUG14579_pointers2()->hasLocalData());
+    }
+};
+
+
+void tst_QThreadStorage::QTBUG14579_leakInDestructor()
+{
+    class Thread : public QThread
+    {
+    public:
+        QThreadStorage<QTBUG14579_class *> &tls;
+
+        Thread(QThreadStorage<QTBUG14579_class *> &t) : tls(t) { }
+
+        void run()
+        {
+            QVERIFY(!tls.hasLocalData());
+            tls.setLocalData(new QTBUG14579_class);
+            QVERIFY(tls.hasLocalData());
+        }
+    };
+    int c = SPointer::count;
+
+    QThreadStorage<QTBUG14579_class *> tls;
+
+    QVERIFY(!QTBUG14579_pointers1()->hasLocalData());
+    QThreadStorage<int *> tls2; //add some more tls to make sure ids are not following each other too much
+    QThreadStorage<int *> tls3;
+    QVERIFY(!tls2.hasLocalData());
+    QVERIFY(!tls3.hasLocalData());
+    QVERIFY(!tls.hasLocalData());
+
+    Thread t1(tls);
+    Thread t2(tls);
+    Thread t3(tls);
+
+    t1.start();
+    t2.start();
+    t3.start();
+
+    QVERIFY(t1.wait());
+    QVERIFY(t2.wait());
+    QVERIFY(t3.wait());
+
+    //check all the constructed things have been destructed
+    QCOMPARE(int(SPointer::count), c);
+}
+
 QTEST_MAIN(tst_QThreadStorage)
 #include "tst_qthreadstorage.moc"
-- 
1.7.3.2