Process finished with exit code -1073740791 (0xC0000409,stack buffer overflow?) in pyqt5

I wrote the code as below. (I tried to create a program that opens a file with QFileDilaog and displays it in a Label.) But the program ended with "Process finished with exit code -1073740791 (0xC0000409)".

As far as I know, 0xC0000409 is a stack buffer overflow,

Why is this happening and how do I fix it?

import sys

import PyQt5
from PyQt5.QtGui import *
from PyQt5.QtCore import *
from PyQt5.QtWidgets import *
from PyQt5 import uic

class QMainDialog(QDialog):
    def __init__(self):
        QDialog.__init__(self, None)
        uic.loadUi(ui,self)

        self.open.clicked.connect(self.Numclicked)


    def Numclicked(self):
        fname = QFileDialog.getOpenFileName(self)
        pixmap = QPixmap(fname)
        imagelabel.setPixmap(pixmap)


app = QApplication(sys.argv)
main_dialog = QMainDialog()
main_dialog.show()
app.exec_()

I use pycharm.

ui :

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>Dialog</class>
 <widget class="QDialog" name="Dialog">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>1108</width>
    <height>716</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>Dialog</string>
  </property>
  <widget class="QPushButton" name="open">
   <property name="geometry">
    <rect>
     <x>900</x>
     <y>620</y>
     <width>181</width>
     <height>61</height>
    </rect>
   </property>
   <property name="text">
    <string>open</string>
   </property>
  </widget>
  <widget class="QLabel" name="imagelabel">
   <property name="geometry">
    <rect>
     <x>20</x>
     <y>20</y>
     <width>1061</width>
     <height>581</height>
    </rect>
   </property>
   <property name="text">
    <string>  image</string>
   </property>
  </widget>
 </widget>
 <resources/>
 <connections/>
</ui>