title: Navigation controller popViewControllerAnimated : yes is not working as expected
body: <p>I am using following line of code:</p>
  
  <pre><code>[self.navigationController popViewControllerAnimated:YES];
  </code></pre>
  
  <p>But it is not behaving in ios 7 as it doing in ios 6.Some times it does not pop controller while we are pressing back button 2- 3 times in succession.<br>
  Resulting in abrupt behaviour in navigation bar and deallocating a controller but showing the same on ui .<br>
  So when we press anything on that controller it results to a crash since controller is already deallocated.</p>