ERROR ThreadError: deadlock; recursive locking

    /home/bug/.rvm/gems/ruby-1.9.2-p180/bundler/gems/rack-404f2f167f9f/lib/rack/lock.rb:14:in `lock'
    /home/bug/.rvm/gems/ruby-1.9.2-p180/bundler/gems/rack-404f2f167f9f/lib/rack/lock.rb:14:in `call'
    /home/bug/.rvm/gems/ruby-1.9.2-p180/bundler/gems/rails-7d1782a2c150/actionpack/lib/action_dispatch/middleware/static.rb:53:in `call'
    /home/bug/.rvm/gems/ruby-1.9.2-p180/bundler/gems/rails-7d1782a2c150/railties/lib/rails/engine.rb:438:in `call'
    /home/bug/.rvm/gems/ruby-1.9.2-p180/bundler/gems/rails-7d1782a2c150/railties/lib/rails/rack/content_length.rb:16:in `call'
    /home/bug/.rvm/gems/ruby-1.9.2-p180/bundler/gems/rails-7d1782a2c150/railties/lib/rails/rack/log_tailer.rb:14:in `call'
    /home/bug/.rvm/gems/ruby-1.9.2-p180/bundler/gems/rack-404f2f167f9f/lib/rack/handler/webrick.rb:59:in `service'
    /home/bug/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/webrick/httpserver.rb:111:in `service'
    /home/bug/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/webrick/httpserver.rb:70:in `run'
    /home/bug/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/webrick/server.rb:183:in `block in start_thread'

It comes to webrick console when there is some errors in stylesheet compilation (e.g. importing file that does not exists)