3 files changed, 13 insertions, 4 deletions
diff --git a/src/kernel/qapplication.cpp b/src/kernel/qapplication.cpp
index a9c9fb8..f3b0119 100644
--- a/src/kernel/qapplication.cpp
+++ b/src/kernel/qapplication.cpp
@@ -2767,7 +2767,10 @@ bool QApplication::internalNotify( QObject *receiver, QEvent * e)
 
     if (!handled) {
 #if defined(QT_THREAD_SUPPORT)
-	bool locked = QApplication::qt_mutex->locked();
+	bool locked = false;
+	if (QApplication::qt_mutex) {
+	    locked = QApplication::qt_mutex->locked();
+	}
 	if (locked) {
 	    QApplication::qt_mutex->unlock();
 	}
@@ -2775,7 +2778,9 @@ bool QApplication::internalNotify( QObject *receiver, QEvent * e)
 	consumed = receiver->event( e );
 #if defined(QT_THREAD_SUPPORT)
 	if (locked) {
-	    QApplication::qt_mutex->lock();
+	    if (QApplication::qt_mutex) {
+		QApplication::qt_mutex->lock();
+	    }
 	}
 #endif
     }
diff --git a/src/kernel/qeventloop_unix.cpp b/src/kernel/qeventloop_unix.cpp
index 202ef12..80c8f29 100644
--- a/src/kernel/qeventloop_unix.cpp
+++ b/src/kernel/qeventloop_unix.cpp
@@ -562,6 +562,8 @@ int QEventLoop::activateTimers()
 	    n_act++;
 	QTimerEvent e( t->id );
 	QApplication::sendEvent( t->obj, &e );	// send event
+	if ( !timerList )	// sendEvent allows other threads to execute, therefore we must check for list existence when it returns!
+	    return 0;
 	if ( timerList->findRef( begin ) == -1 )
 	    begin = 0;
     }
diff --git a/src/kernel/qeventloop_x11.cpp b/src/kernel/qeventloop_x11.cpp
index cd3e865..5ee41ca 100644
--- a/src/kernel/qeventloop_x11.cpp
+++ b/src/kernel/qeventloop_x11.cpp
@@ -284,7 +284,8 @@ bool QEventLoop::processEvents( ProcessEventsFlags flags )
     // unlock the GUI mutex and select.  when we return from this function, there is
     // something for us to do
 #if defined(QT_THREAD_SUPPORT)
-    locker.mutex()->unlock();
+    if ( locker.mutex() ) locker.mutex()->unlock();
+    else return false;
 #endif
 
     int nsel;
@@ -298,7 +299,8 @@ bool QEventLoop::processEvents( ProcessEventsFlags flags )
 
     // relock the GUI mutex before processing any pending events
 #if defined(QT_THREAD_SUPPORT)
-    locker.mutex()->lock();
+    if ( locker.mutex() ) locker.mutex()->lock();
+    else return false;
 #endif
 
     // we are awake, broadcast it