SystemCallError on FileUtils.mkdir_p

HOWTO

JAVA_OPTS="-Djava.security.manager -Djava.security.policy=test.policy" VERIFY_JRUBY=true jruby -e "require 'fileutils'; FileUtils.mkdir_p '/tmp/hello/world'"

test.policy

grant {
    permission java.util.PropertyPermission "*", "read,write";
    permission java.lang.RuntimePermission "*";
    permission java.lang.reflect.ReflectPermission "*";
//    permission java.io.FilePermission "<<ALL FILES>>", "read, execute";
    permission java.io.FilePermission ".jrubyrc", "read, execute";
    permission java.io.FilePermission "${user.home}/.jrubyrc", "read, execute";
    permission java.io.FilePermission "${user.home}/.rvm/rubies/jruby-9.1.6.0", "read, execute";
    permission java.io.FilePermission "${user.home}/.rvm/rubies/jruby-9.1.6.0/-", "read, execute";
    permission java.io.FilePermission "/tmp", "read, write, execute";
    permission java.io.FilePermission "/tmp/-", "read, write, execute";
};