Posix::Spawn::Child gets stuck when restarting service

[hkraji]

I've tested this on ruby1.9 and ruby2.0 and tried different versions of posix-spawn gem. These include 0.3.5, 0.3.9, 0.3.11. This snippet I had ran on Amazon Linux as root user. Here is example of code:

    require 'pp'
    require 'posix-spawn'
    # I've used mcollective here, but other services I've tried gave same result
    formulate_command = "service mcollective restart"
    pp 'start'
    process = POSIX::Spawn::Child.new(formulate_command)
    pp process
    pp 'end'

This will freeze and it will never return process object, I've debugged code and it freezes on line https://github.com/rtomayko/posix-spawn/blob/master/lib/posix/spawn/child.rb#L228.

Interesting thing is, if I run same command with sudo prefix it will work.

Also both commands will work if run with Kernel#system and Kernel#``. POSIX::Spawn#popen4` will also not work for case described above.

EDIT

After some investigation I find that this issue is probably related to this http://stackoverflow.com/questions/8952043/how-to-fix-hanging-popen3-in-ruby