diff --git a/src/core/kernel/qcoreapplication.cpp b/src/core/kernel/qcoreapplication.cpp
index 4fc8694f0..9ca952efa 100644
--- a/src/core/kernel/qcoreapplication.cpp
+++ b/src/core/kernel/qcoreapplication.cpp
@@ -49,6 +49,19 @@
 
 QT_BEGIN_NAMESPACE
 
+class QMutexUnlocker
+{
+public:
+    inline explicit QMutexUnlocker(QMutex *m) : mtx(m) { }
+    inline ~QMutexUnlocker() { unlock(); }
+    inline void unlock() { if (mtx) mtx->unlock(); mtx = 0; }
+
+private:
+    Q_DISABLE_COPY(QMutexUnlocker)
+
+    QMutex *mtx;
+};
+
 bool QCoreApplicationPrivate::checkInstance(const char *function)
 {
     if (Q_UNLIKELY(!QCoreApplication::self)) {
@@ -818,7 +831,7 @@ void QCoreApplication::postEvent(QObject *receiver, QEvent *event, int priority)
     }
 
     // lock the post event mutex
-    QMutexLocker locker(&data->postEventList.mutex);
+    data->postEventList.mutex.lock();
 
     // if object has moved to another thread, follow it
     while (data != *pdata) {
@@ -834,6 +847,8 @@ void QCoreApplication::postEvent(QObject *receiver, QEvent *event, int priority)
         data->postEventList.mutex.lock();
     }
 
+    QMutexUnlocker locker(&data->postEventList.mutex);
+
     // if this is one of the compressible events, do compression
     if (receiver->d_func()->postedEvents
         && self && self->compressEvent(event, receiver, &data->postEventList)) {