title: Marshmallow - dex2oat ~ permission denied
body: <p>Got forced close when trying to start CameraApp:</p>
  
  <pre><code>08-15 15:36:19.807 E/dex2oat (29758): Failed to create oat file: /data/dalvik-cache/arm/system@priv-app@LGCameraApp@LGCameraApp.apk@classes.dex: Permission denied
  </code></pre>
  
  <ul>
  <li>the file does exist on the stated path, why is it trying to dex2oat again?</li>
  <li>suspect this app also gets "optimized" every time when the phone boots up</li>
  </ul>
  
  <p>Can logcat provide boot-up app optimization log?  Which keyword should I look for?</p>