mattr_accessor :config for module raises error (actionpack) after server restart

mattr_accessor :config for module raises error (actionpack) after server restart.
Putting for example the following in config/initializers/break_it.rb

module BreakIt
  mattr_accessor :config
end
ApplicationController.send(:include, BreakIt)

raises an error the first time a pare is requested after the servers starts (confirmed for webrick and thin):
.... undefined method allow_forgery_protection' for nil:NilClass .... actionpack (3.0.7) lib/action_controller/metal/request_forgery_protection.rb:123:inprotect_against_forgery?'

A similar error, not reproduced here was because:
actionpack (3.0.7) lib/abstract_controller/rendering.rb:131 => protected_instance_variables was nil instead of an array.

I renamed :config to something else to fix it. So low priority, but good to mention I think.