[ruby-core:115600] [Ruby master Bug#20042] ObjectSpace finalizer can cause segfault

6 Dec 2023

      Issue #20042 has been updated by byroot (Jean Boussier).

Backport changed from 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN to 3.0: DONTNEED, 3.1: REQUIRED, 3.2: REQUIRED

It started on 3.1:

```
:ok: 1.8 -- 3.0
(no stdout :speak_no_evil:)
:ok: 3.1,3.2
<internal:gc>:34: warning: Exception in finalizer #<Method: Object#fin() -:2>
-:2:in `fin': wrong number of arguments (given 1, expected 0) (ArgumentError)
    from <internal:gc>:34:in `call'
    from <internal:gc>:34:in `start'
    from -:7:in `<main>'

:ok: 7e05e9ff94 (2023-12-06T06:48:55Z)
<internal:gc>:39: warning: Exception in finalizer #<Method: Object#fin() -:2>
-:2:in `fin': wrong number of arguments (given 1, expected 0) (ArgumentError)
    from <internal:gc>:39:in `call'
    from <internal:gc>:39:in `start'
    from -:7:in `<main>'
```

----------------------------------------
Bug #20042: ObjectSpace finalizer can cause segfault
https://bugs.ruby-lang.org/issues/20042#change-105530

* Author: ioquatix (Samuel Williams)
* Status: Open
* Priority: Normal
* Assignee: ko1 (Koichi Sasada)
* Backport: 3.0: DONTNEED, 3.1: REQUIRED, 3.2: REQUIRED
----------------------------------------
```ruby
class Finalizer
  def call # <- missing (id) argument
  end
end

object = Object.new
ObjectSpace.define_finalizer(object, Finalizer.new)
object = nil

GC.start # segfaults here
```

-- 
https://bugs.ruby-lang.org/