Deadlock on wait_for_termination

Hey, I have a deadlock problem, code snippet like this:

thread_pool = Concurrent::FixedThreadPool.new(3)
res = Concurrent::ThreadLocalVar.new({})
while @queue.size > 0 do
  thread_pool.post do
    cur = @queue.pop
    build_res = start(cur)
    do_sth(res)
  end
end
thread_pool.shutdown
thread_pool.wait_for_termination

Then here is what I got:

/RHEL5_64/DEV.STD.PTHREAD/build/private/env/ruby2.3.x/ruby2.3.x/lib/ruby/gems/2.3.0/gems/concurrent-ruby-1.0.5/lib/concurrent/synchronization/mri_lockable_object.rb:43:in `sleep': No live threads left. Deadlock? (fatal)
	from /RHEL5_64/DEV.STD.PTHREAD/build/private/env/ruby2.3.x/ruby2.3.x/lib/ruby/gems/2.3.0/gems/concurrent-ruby-1.0.5/lib/concurrent/synchronization/mri_lockable_object.rb:43:in `wait'
	from RHEL5_64/DEV.STD.PTHREAD/build/private/env/ruby2.3.x/ruby2.3.x/lib/ruby/gems/2.3.0/gems/concurrent-ruby-1.0.5/lib/concurrent/synchronization/mri_lockable_object.rb:43:in `ns_wait'
	from RHEL5_64/DEV.STD.PTHREAD/build/private/env/ruby2.3.x/ruby2.3.x/lib/ruby/gems/2.3.0/gems/concurrent-ruby-1.0.5/lib/concurrent/synchronization/abstract_lockable_object.rb:43:in `ns_wait_until'
	from RHEL5_64/DEV.STD.PTHREAD/build/private/env/ruby2.3.x/ruby2.3.x/lib/ruby/gems/2.3.0/gems/concurrent-ruby-1.0.5/lib/concurrent/atomic/event.rb:87:in `block in wait'
	from RHEL5_64/DEV.STD.PTHREAD/build/private/env/ruby2.3.x/ruby2.3.x/lib/ruby/gems/2.3.0/gems/concurrent-ruby-1.0.5/lib/concurrent/synchronization/mri_lockable_object.rb:38:in `block in synchronize'
	from RHEL5_64/DEV.STD.PTHREAD/build/private/env/ruby2.3.x/ruby2.3.x/lib/ruby/gems/2.3.0/gems/concurrent-ruby-1.0.5/lib/concurrent/synchronization/mri_lockable_object.rb:38:in `synchronize'
	from RHEL5_64/DEV.STD.PTHREAD/build/private/env/ruby2.3.x/ruby2.3.x/lib/ruby/gems/2.3.0/gems/concurrent-ruby-1.0.5/lib/concurrent/synchronization/mri_lockable_object.rb:38:in `synchronize'
	from RHEL5_64/DEV.STD.PTHREAD/build/private/env/ruby2.3.x/ruby2.3.x/lib/ruby/gems/2.3.0/gems/concurrent-ruby-1.0.5/lib/concurrent/atomic/event.rb:84:in `wait'
	from RHEL5_64/DEV.STD.PTHREAD/build/private/env/ruby2.3.x/ruby2.3.x/lib/ruby/gems/2.3.0/gems/concurrent-ruby-1.0.5/lib/concurrent/executor/ruby_executor_service.rb:49:in `wait_for_termination'
	from package_builder.rb:64:in `bulk_build'
	from lib/test.rb:152:in `<main>'
rake aborted!

Can someone help me out?

Start by reviewing concurrent/executor/ruby_executor_service.rb and concurrent/atomic/event.rb around wait_for_termination and wait, then reproduce the reported FixedThreadPool example on the stated Ruby setup. Done means the example no longer deadlocks or the issue is clearly explained with a confirmed cause and regression coverage.