Bug #10282: Reproducible segfault when inspecting this method

• Status: Closed
• Assignee: -
• Target version: 2.2.0
• ruby -v: 2.1.2
• Backport: 2.0.0: DONTNEED, 2.1: DONE

[schnittchen (Thomas Stratmann)]

The example code can be found here (in this exact comment): https://github.com/pry/pry/issues/1299#issuecomment-56389004

I have taken the time to reduce it as far as this. It should be easily reproduced on other systems/versions now.

[normalperson (Eric Wong)]

• File 0001-object.c-rb_class_real-do-not-dereference-0-VALUE.patch 0001-object.c-rb_class_real-do-not-dereference-0-VALUE.patch added
• Category set to core
• Target version set to 2.2.0
• Backport changed from 2.0.0: UNKNOWN, 2.1: UNKNOWN to 2.0.0: DONTNEED, 2.1: REQUIRED

This looks to be a simple dereference bug.
However, this is my first time looking a prepend so maybe there's a subtle
behavior change I missed.

"make check" and rubyspec passes, at least.

• Status changed from Open to Closed
• % Done changed from 0 to 100

Applied in changeset r47715.

---

object.c (rb_class_real): do not dereference 0 VALUE

• test/ruby/test_module.rb (test_inspect_segfault):
  Test case and bug report by Thomas Stratmann.
  [ruby-core:65214] [Bug #10282]

[normalperson (Eric Wong)]

[e-mail] wrote:

File 0001-object.c-rb_class_real-do-not-dereference-0-VALUE.patch added

This looks to be a simple dereference bug.
However, this is my first time looking a prepend so maybe there's a subtle
behavior change I missed.

Committed as r47715; I don't think this breaks existing code
(but even if it did, it's better than segfaulting).

"make check" and rubyspec passes, at least.

[nagachika (Tomoyuki Chikanaga)]

• Backport changed from 2.0.0: DONTNEED, 2.1: REQUIRED to 2.0.0: DONTNEED, 2.1: DONE

Backported into ruby_2_1 at r47957.