malloc_zone_unregister failure on Rails server start
I ran into this too. I compared your Gemfile.lock with mine as a last ditch effort after some googling and found that I was using the same version of skylight.
For anyone that comes across this post, upgrading skylight to 0.10.6 might fix the issue for you too.
Short of that, it might be worth selectively removing dependencies like sqlite3 or mysql that could also be the culprit until the app boots.