CLONE - createdibsection failed when enlarge the subwindow size and much memory used in main program

When much memory (about 1.2GB) is used in my Qt application, one new window (subclass of QWidget) for QGraphicsView shown caused the issue "createdib: createdibsection failed." , then the application crashed immediately. But the total memory in machine is 16GB which is large enough.
Additionally, sometimes the new window can be shown normally but it crashed when the window size was enlarged. And the debugging of resizeEvent is correct.