Bug #13859: Segfault running `Fiber#inspect` on trunk

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: ruby 2.5.0dev (2017-09-01 trunk 59716) [x86_64-darwin15]
• Backport: 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: UNKNOWN

[alexgenco (Alex Genco)]

I started encountering segfaults on ruby-head in the test suite for neovim-ruby a couple weeks ago (e.g. https://travis-ci.org/alexgenco/neovim-ruby/jobs/268931902).

After some digging, it looks like the segfaults are being caused by Fiber#inspect. Here's a minimal reproduction:

ruby -r fiber -e "Fiber.current.inspect"

I did a git bisect and it seems to be related to this commit: https://github.com/ruby/ruby/commit/43384ae9788be243746849ee54d9f5c8f7e0412b

Segfault output is attached. Please let me know if you need more information. Thanks!

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Closed

Applied in changeset trunk|r59721.

---

cont.c: fix root fiber to_s

• cont.c (fiber_to_s): fix Fiber#to_s on root fibers which have no
  procs. [ruby-core:82629] [Bug #13859]