mysql2 EINTR on connect prolonged timeout reproduction

test2.rb

#!/usr/bin/env ruby

require 'mysql2'
require 'rbconfig'

CONNECT_TIMEOUT = ARGV.empty? ? nil : ARGV.shift.to_i

trap("USR2") {}

HOST = case RbConfig::CONFIG["host_os"]
       when /\Adarwin/
         '127.0.0.2'
       when /\Alinux/
         '169.254.1.2'
       else
         ARGV.shift or abort("Usage: #{$0} HOST")
       end

pid = fork do
  client = Mysql2::Client.new(:host => HOST, :connect_timeout => CONNECT_TIMEOUT)
  client.close
end

loop do
  sleep 0.1
  Process.kill("USR2", pid)
  break if Process.waitpid(pid, Process::WNOHANG)
end
puts $?.to_s