rails consoleでカーソルキーを使うと直ちにクラッシュするのはなぜなんだぜ？

四半年ほど悩んでいるのですが、いっこうに解決する気配がなくて困っています。今のところ、Ruby2.0系とRails3.2系の組み合わせでのみ起きています。Ruby1.9系で問題ないし、irbはRubyのバージョンに関係なく問題ないんですけど…？ちなみに以下のようになります。

$ bundle exec rails c
Loading development environment (Rails 3.2.14)
irb(main):001:0> (ここでカーソルキーを押す)/Users/yuuxxxx/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rb-readline-0.4.2/lib/rbreadline.rb:4269:in `block in _rl_dispatch_subseq': invalid byte sequence in UTF-8 (ArgumentError)
  from /Users/yuuxxxx/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rb-readline-0.4.2/lib/rbreadline.rb:4269:in `each'
  from /Users/yuuxxxx/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rb-readline-0.4.2/lib/rbreadline.rb:4269:in `detect'
  from /Users/yuuxxxx/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rb-readline-0.4.2/lib/rbreadline.rb:4269:in `_rl_dispatch_subseq'
  from /Users/yuuxxxx/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rb-readline-0.4.2/lib/rbreadline.rb:4271:in `_rl_dispatch_subseq'
  from /Users/yuuxxxx/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rb-readline-0.4.2/lib/rbreadline.rb:4251:in `_rl_dispatch'
  from /Users/yuuxxxx/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rb-readline-0.4.2/lib/rbreadline.rb:4669:in `readline_internal_charloop'
  from /Users/yuuxxxx/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rb-readline-0.4.2/lib/rbreadline.rb:4743:in `readline_internal'
  from /Users/yuuxxxx/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rb-readline-0.4.2/lib/rbreadline.rb:4765:in `readline'
  from /Users/yuuxxxx/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rb-readline-0.4.2/lib/readline.rb:40:in `readline'
  from /Users/yuuxxxx/.rbenv/versions/2.0.0-p247/lib/ruby/2.0.0/irb/input-method.rb:152:in `gets'
  from /Users/yuuxxxx/.rbenv/versions/2.0.0-p247/lib/ruby/2.0.0/irb.rb:472:in `block (2 levels) in eval_input'
  from /Users/yuuxxxx/.rbenv/versions/2.0.0-p247/lib/ruby/2.0.0/irb.rb:624:in `signal_status'
  from /Users/yuuxxxx/.rbenv/versions/2.0.0-p247/lib/ruby/2.0.0/irb.rb:471:in `block in eval_input'
  from /Users/yuuxxxx/.rbenv/versions/2.0.0-p247/lib/ruby/2.0.0/irb/ruby-lex.rb:190:in `call'
  from /Users/yuuxxxx/.rbenv/versions/2.0.0-p247/lib/ruby/2.0.0/irb/ruby-lex.rb:190:in `buf_input'
  from /Users/yuuxxxx/.rbenv/versions/2.0.0-p247/lib/ruby/2.0.0/irb/ruby-lex.rb:105:in `getc'
  from /Users/yuuxxxx/.rbenv/versions/2.0.0-p247/lib/ruby/2.0.0/irb/slex.rb:206:in `match_io'
  from /Users/yuuxxxx/.rbenv/versions/2.0.0-p247/lib/ruby/2.0.0/irb/slex.rb:76:in `match'
  from /Users/yuuxxxx/.rbenv/versions/2.0.0-p247/lib/ruby/2.0.0/irb/ruby-lex.rb:290:in `token'
  from /Users/yuuxxxx/.rbenv/versions/2.0.0-p247/lib/ruby/2.0.0/irb/ruby-lex.rb:266:in `lex'
  from /Users/yuuxxxx/.rbenv/versions/2.0.0-p247/lib/ruby/2.0.0/irb/ruby-lex.rb:237:in `block (2 levels) in each_top_level_statement'
  from /Users/yuuxxxx/.rbenv/versions/2.0.0-p247/lib/ruby/2.0.0/irb/ruby-lex.rb:233:in `loop'
  from /Users/yuuxxxx/.rbenv/versions/2.0.0-p247/lib/ruby/2.0.0/irb/ruby-lex.rb:233:in `block in each_top_level_statement'
  from /Users/yuuxxxx/.rbenv/versions/2.0.0-p247/lib/ruby/2.0.0/irb/ruby-lex.rb:232:in `catch'
  from /Users/yuuxxxx/.rbenv/versions/2.0.0-p247/lib/ruby/2.0.0/irb/ruby-lex.rb:232:in `each_top_level_statement'
  from /Users/yuuxxxx/.rbenv/versions/2.0.0-p247/lib/ruby/2.0.0/irb.rb:488:in `eval_input'
  from /Users/yuuxxxx/.rbenv/versions/2.0.0-p247/lib/ruby/2.0.0/irb.rb:397:in `block in start'
  from /Users/yuuxxxx/.rbenv/versions/2.0.0-p247/lib/ruby/2.0.0/irb.rb:396:in `catch'
  from /Users/yuuxxxx/.rbenv/versions/2.0.0-p247/lib/ruby/2.0.0/irb.rb:396:in `start'
  from /Users/yuuxxxx/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/railties-3.2.14/lib/rails/commands/console.rb:47:in `start'
  from /Users/yuuxxxx/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/railties-3.2.14/lib/rails/commands/console.rb:8:in `start'
  from /Users/yuuxxxx/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/railties-3.2.14/lib/rails/commands.rb:41:in `<top (required)>'
  from script/rails:6:in `require'
  from script/rails:6:in `<main>'

エラーの起きたgemを見る限り、readlineのバグ？