Issue #8080 has been updated by kosaki (Motohiro KOSAKI). Hi nagachika-sanm You need backport 39777, 39779, 39781 and 39783 too. ---------------------------------------- Backport #8080: Segfault in rb_fd_set https://bugs.ruby-lang.org/issues/8080#change-37667 Author: jonleighton (Jon Leighton) Status: Assigned Priority: High Assignee: nagachika (Tomoyuki Chikanaga) Category: Target version: I have experienced a segfault with Ruby 2 during an IO.select call: See https://travis-ci.org/jonleighton/spring/jobs/5393025 or https://gist.github.com/jonleighton/5147785 to see the crash output. I cannot reproduce on a different version of Linux (Fedora). However I was able to reproduce by downloading a VM image of the Travis CI environment and running the code on there (see http://pivotallabs.com/debugging-travis-builds/ for how to do that). I tried to produce a simple script to reproduce, but without success. I also tried to build Ruby 2 with debugging symbols, but this did not produce the crash. I'm not sure why - perhaps related to compiler optimisations. I found a workaround for the crash with https://github.com/jonleighton/spring/commit/c8a7afdd3238ef88bffc2c8f56baa21042400e15. -- http://bugs.ruby-lang.org/