broken interactions with bullet, appsignal gems, possibly puma

[mrbrdo]

I'm having problems with this gem in combination with bullet gem. If I comment out Bullet.enable then profiler starts showing up.
I am loading rack-mini-profiler manually in a Rails initializer (with require: false in Gemfile).

I noticed it seems to hang on mutex lock in the middleware, because if I press ctrl-c while profiler is "stuck" loading the results, I get the backtrace shown at the end of this post.

Also a similar thing seems to be happening with appsignal gem.

I am using puma so this may be related to #70

^CExiting
2014-10-16 15:30:35 +0200: Rack app error: #<ThreadError: Attempt to unlock a mutex which is not locked>2014-10-16 15:30:35 +0200: Rack app error: #<ThreadError: Attempt to unlock a mutex which is not locked>
/path/gems/rack-1.5.2/lib/rack/lock.rb:22:in `unlock'
/path/gems/rack-1.5.2/lib/rack/lock.rb:22:in `ensure in call'
/path/gems/rack-1.5.2/lib/rack/lock.rb:23:in `call'
/path/gems/actionpack-4.1.6/lib/action_dispatch/middleware/static.rb:64:in `call'
/path/gems/rack-1.5.2/lib/rack/sendfile.rb:112:in `call'
/Users/me/.rvm/gems/r
2014-10-16 15:30:35 +0200: Rack app error: #<ThreadError: Attempt to unlock a mutex which is not locked>
/path/gems/rack-1.5.2/lib/rack/lock.rb:22:in `unlock'
/path/gems/rack-1.5.2/lib/rack/lock.rb:22:in `ensure in call'
/path/gems/rack-1.5.2/lib/rack/lock.rb:23:in `call'
/path/gems/actionpack-4.1.6/lib/action_dispatch/middleware/static.rb:64:in `call'
/path/gems/rack-1.5.2/lib/rack/sendfile.rb:112:in `call'
/path/gems/rack-mini-profiler-0.9.2/lib/mini_profiler/profiler.rb:193:in `call'
/path/gems/railties-4.1.6/lib/rails/engine.rb:514:in `call'
/path/gems/railties-4.1.6/lib/rails/application.rb:144:in `call'
/path/gems/rack-1.5.2/lib/rack/content_length.rb:14:in `call'
/path/gems/puma-2.9.1/lib/puma/server.rb:490:in `handle_request'
/Users/me/.rvm/gems/r/path/gems/rack-1.5.2/lib/rack/lock.rb:22:in `unlock'
/path/gems/rack-1.5.2/lib/rack/lock.rb:22:in `ensure in call'
/path/gems/rack-1.5.2/lib/rack/lock.rb:23:in `call'
/path/gems/actionpack-4.1.6/lib/action_dispatch/middleware/static.rb:64:in `call'
/path/gems/rack-1.5.2/lib/rack/sendfile.rb:112:in `call'
/path/gems/rack-mini-profiler-0.9.2/lib/mini_profiler/profiler.rb:193:in `call'
/path/gems/railties-4.1.6/lib/rails/engine.rb:514:in `call'
/path/gems/railties-4.1.6/lib/rails/application.rb:144:in `call'
/path/gems/rack-1.5.2/lib/rack/content_length.rb:14:in `call'
/path/gems/puma-2.9.1/lib/puma/server.rb:490:in `handle_request'
/Users/me/.rvm/gems/r2014-10-16 15:30:35 +0200: Rack app error: #<ThreadError: Attempt to unlock a mutex which is not locked>
/path/gems/rack-1.5.2/lib/rack/lock.rb:22:in `unlock'
/path/gems/rack-1.5.2/lib/rack/lock.rb:22:in `ensure in call'
/path/gems/rack-1.5.2/lib/rack/lock.rb:23:in `call'
/path/gems/actionpack-4.1.6/lib/action_dispatch/middleware/static.rb:64:in `call'
/path/gems/rack-1.5.2/lib/rack/sendfile.rb:112:in `call'
/path/gems/rack-mini-profiler-0.9.2/lib/mini_profiler/profiler.rb:193:in `call'
/path/gems/railties-4.1.6/lib/rails/engine.rb:514:in `call'
/path/gems/railties-4.1.6/lib/rails/application.rb:144:in `call'
/path/gems/rack-1.5.2/lib/rack/content_length.rb:14:in `call'
/path/gems/puma-2.9.1/lib/puma/server.rb:490:in `handle_request'
/Users/me/.rvm/gems/r2014-10-16 15:30:35 +0200: Rack app error: #<ThreadError: Attempt to unlock a mutex which is not locked>
/path/gems/rack-1.5.2/lib/rack/lock.rb:22:in `unlock'
/path/gems/rack-1.5.2/lib/rack/lock.rb:22:in `ensure in call'
/path/gems/rack-1.5.2/lib/rack/lock.rb:23:in `call'
/path/gems/actionpack-4.1.6/lib/action_dispatch/middleware/static.rb:64:in `call'
/path/gems/rack-1.5.2/lib/rack/sendfile.rb:112:in `call'
/path/gems/rack-mini-profiler-0.9.2/lib/mini_profiler/profiler.rb:193:in `call'
/path/gems/railties-4.1.6/lib/rails/engine.rb:514:in `call'
/path/gems/railties-4.1.6/lib/rails/application.rb:144:in `call'
/path/gems/rack-1.5.2/lib/rack/content_length.rb:14:in `call'
/path/gems/puma-2.9.1/lib/puma/server.rb:490:in `handle_request'
/path/gems/rack-mini-profiler-0.9.2/lib/mini_profiler/profiler.rb:193:in `call'
/path/gems/railties-4.1.6/lib/rails/engine.rb:514:in `call'
/path/gems/railties-4.1.6/lib/rails/application.rb:144:in `call'
/path/gems/rack-1.5.2/lib/rack/content_length.rb:14:in `call'
/path/gems/puma-2.9.1/lib/puma/server.rb:490:in `handle_request'
/path/gems/puma-2.9.1/lib/puma/server.rb:361:in `process_client'
/path/gems/puma-2.9.1/lib/puma/server.rb:254:in `block in run'
/path/gems/puma-2.9.1/lib/puma/thread_pool.rb:92:in `call'
/path/gems/puma-2.9.1/lib/puma/thread_pool.rb:92:in `block in spawn_thread'
uby-2.1.2@project/gems/puma-2.9.1/lib/puma/server.rb:361:in `process_client'
/path/gems/puma-2.9.1/lib/puma/server.rb:254:in `block in run'
/path/gems/puma-2.9.1/lib/puma/thread_pool.rb:92:in `call'
/path/gems/puma-2.9.1/lib/puma/thread_pool.rb:92:in `block in spawn_thread'uby-2.1.project/gems/puma-2.9.1/lib/puma/server.rb:361:in `process_client'
/path/gems/puma-2.9.1/lib/puma/server.rb:254:in `block in run'
/path/gems/puma-2.9.1/lib/puma/thread_pool.rb:92:in `call'
/path/gems/puma-2.9.1/lib/puma/thread_pool.rb:92:in `block in spawn_thread'

uby-2.1.2@project/gems/puma-2.9.1/lib/puma/server.rb:361:in `process_client'
/path/gems/puma-2.9.1/lib/puma/server.rb:254:in `block in run'
/path/gems/puma-2.9.1/lib/puma/thread_pool.rb:92:in `call'
/path/gems/puma-2.9.1/lib/puma/thread_pool.rb:92:in `block in spawn_thread'
uby-2.1.2@project/gems/puma-2.9.1/lib/puma/server.rb:361:in `process_client'
/path/gems/puma-2.9.1/lib/puma/server.rb:254:in `block in run'
/path/gems/puma-2.9.1/lib/puma/thread_pool.rb:92:in `call'
/path/gems/puma-2.9.1/lib/puma/thread_pool.rb:92:in `block in spawn_thread'

[mrbrdo]

If I enable bullet in the initializer where I load rack-mini-profiler, just after, it will work on the first request but then when I try to reload the page it just hangs. Unless I use multithreaded puma mode, but that is not meant for development anyway.