Issue #9538 has been reported by Masahiro Nakagawa.

----------------------------------------
Backport #9538: backport r45047
https://bugs.ruby-lang.org/issues/9538

* Author: Masahiro Nakagawa
* Status: Open
* Priority: Normal
* Assignee: 
----------------------------------------
Related issue: https://bugs.ruby-lang.org/issues/9525

This problem is a big issue for Fluentd. 
Please backport this commit to Ruby 1.9.3.



-- 
http://bugs.ruby-lang.org/