Issue #9352 has been updated by tmm1 (Aman Gupta). @nobu cleaned up the patch in r44496, so that can be backported instead of r44490 ---------------------------------------- Bug #9352: [BUG] rb_sys_fail_str(connect(2) for [fe80::1%lo0]:3000) - errno == 0 https://bugs.ruby-lang.org/issues/9352#change-44099 Author: kain (Claudio Poli) Status: Open Priority: Normal Assignee: naruse (Yui NARUSE) Category: core Target version: ruby -v: ruby 2.1.0p0 (2013-12-25 revision 44422) [x86_64-darwin13.0] Backport: 1.9.3: DONTNEED, 2.0.0: DONTNEED, 2.1: REQUIRED I'm seeing this crash attempting to connect to an http unreachable host (127.0.0.1:3000) through Excon, which in turn uses `connect_nonblock`. I'm compiling ruby-trunk at the moment, to try on it as well. -- http://bugs.ruby-lang.org/