title: iOS8 crashed with __CFNOTIFICATIONCENTER_IS_CALLING_OUT_TO_AN_OBSERVER__
body: <pre><code>#0
  Crashed: com.apple.main-thread
  EXC_BAD_ACCESS KERN_INVALID_ADDRESS 0x00000001625fbeb8
  0
  libobjc.A.dylib 
  objc_msgSend + 16
  1   CoreFoundation  
  __CFNOTIFICATIONCENTER_IS_CALLING_OUT_TO_AN_OBSERVER__ + 20
  2   CoreFoundation  
  _CFXNotificationPost + 2060
  3
  Foundation  
  -[NSNotificationCenter postNotificationName:object:userInfo:] + 72
  </code></pre>
  
  <p>The bug occurred infrequently.So It's too hard for me to find out why.
  From the infomation I know It's occurred after a postNotification,but I found all the places where receive the notification and i write this in dealloc "[[NSNotificationCenter defaultCenter] removeObserver:self]".
  Does anyone know any other possibility?</p>