title: iOS app got killed with "Message from debugger: Terminated due to signal 9" after 2 minutes running in background
body: <p>I am developing a navigation like app. It works fine for the location manager to get the device's current location both in foreground and background. </p>
  
  <p>In foreground it works fine for however long. However, when the app goes to background mode, initially the location manager works well. But after around 2 minutes, the app exited and the console shows the error message saying: "Message from debugger: Terminated due to signal 9."</p>
  
  <p>I searched the error message, but still could not find the solution to it.
  <a href="https://stackoverflow.com/questions/42331852/quitting-app-causes-error-message-from-debugger-terminated-due-to-signal-9">Quitting app causes error &quot;Message from debugger: Terminated due to signal 9&quot;</a></p>
  
  <p>I noticed the CPU usage is very high, around 105% in background mode. This could be the reason that the OS send the KILL signal. But even if I decrease the location manager's accuracy (but for navigation purpose I still need the highest accuracy ultimately), the problem is still there.</p>
  
  <p>So I am really wondering how those fitness apps managed to track user's locations in the background for however long without being killed by the OS.</p>