iOS 7 app freezes without crash

Question

I have an app that I am building for iOS 7 only and running on an iPhone 5S. The app sometimes in normal use just freezes up and won't recognize any touch interactions happen and it requires the app to be force quit. I have noticed it doing many different tasks and in different views. I have had this problem while debugging and the RAM usage is at about 65 Mb which I think is pretty good, cpu usage is in the single digits and the debugger doesn't register a crash. Where can I go from here in terms of debugging and trying to fix this pretty serious problem?

Answer 1

To put my comment as an answer, usually when your application freezes, it means either the CPU is doing some heavy lifting or your have a deadlock somewhere. As you mentioned that it was the CPU usage was low, my first guess was a deadlock.

Answer 2

Thanks to Leo Natan for suggesting that it was deadlocks, because it was. There was a specific instance where I was saving and fetching from the background thread and there was an easy solution that made it possible for me to stop fetching on the background thread.