Bug #10847: SystemStackError after NameError prepends a module

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: ruby 2.2.0p0 (2014-12-25 revision 49005) [x86_64-linux]
• Backport: 2.0.0: REQUIRED, 2.1: DONE, 2.2: DONE

[yuki24 (Yuki Nishijima)]

The following code causes SystemStackError.

module Foo
end

NameError.prepend Foo
foo rescue $!

And here is the full backtrace:

system_stack_error_from_name_error.rb:3:in `initialize': stack level too deep (SystemStackError)
	from system_stack_error_from_name_error.rb:3:in `initialize'
	from system_stack_error_from_name_error.rb:3:in `initialize'
	from system_stack_error_from_name_error.rb:3:in `initialize'
	from system_stack_error_from_name_error.rb:3:in `initialize'
	from system_stack_error_from_name_error.rb:3:in `initialize'
	from system_stack_error_from_name_error.rb:3:in `initialize'
	from system_stack_error_from_name_error.rb:3:in `initialize'
	from system_stack_error_from_name_error.rb:3:in `initialize'
	 ... 10907 levels...
	from system_stack_error_from_name_error.rb:3:in `initialize'
	from system_stack_error_from_name_error.rb:3:in `initialize'
	from system_stack_error_from_name_error.rb:3:in `method_missing'
	from system_stack_error_from_name_error.rb:3:in `<main>'

This happens on Ruby 2.0.0, 2,1,5, 2.2.0 and ruby-trunk(rev 49451).

[hanachin (Seiei Miyagi)]

How to reproduce:

1. prepend Module to the class
2. call the method that calls cfunc rb_call_super

The following code causes SystemStackError too, because Float#numerator calls rb_call_super.

module M; end
Float.prepend M

0.3.numerator

I wrote a patch for this issue.

diff --git vm_eval.c vm_eval.c
index 6eeee5f..4039b6c 100644
--- vm_eval.c
+++ vm_eval.c
@@ -273,7 +273,8 @@ vm_call_super(rb_thread_t *th, int argc, const VALUE *argv)
        rb_bug("vm_call_super: should not be reached");
     }

-    klass = RCLASS_SUPER(cfp->klass);
+    klass = RCLASS_ORIGIN(cfp->klass);
+    klass = RCLASS_SUPER(klass);
     id = cfp->me->def->original_id;
     me = rb_method_entry(klass, id, &klass);
     if (!me) {

[nobu (Nobuyoshi Nakada)]

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

Applied in changeset r49867.

---

vm_eval.c: next super class from the original

• vm_eval.c (vm_call_super): search next super class from the
  original class, to get rid of infinite recursion with
  prepending. a patch by Seiei Higa at
  [ruby-core:68434]. [ruby-core:68093] [Bug #10847]

[usa (Usaku NAKAMURA)]

• Has duplicate Bug #10970: Backport r49867 added

[usa (Usaku NAKAMURA)]

• Backport changed from 2.0.0: UNKNOWN, 2.1: UNKNOWN, 2.2: UNKNOWN to 2.0.0: REQUIRED, 2.1: REQUIRED, 2.2: REQUIRED

[nagachika (Tomoyuki Chikanaga)]

• Backport changed from 2.0.0: REQUIRED, 2.1: REQUIRED, 2.2: REQUIRED to 2.0.0: REQUIRED, 2.1: REQUIRED, 2.2: DONE

Backported into ruby_2_2 branch at r50275.

[usa (Usaku NAKAMURA)]

• Backport changed from 2.0.0: REQUIRED, 2.1: REQUIRED, 2.2: DONE to 2.0.0: REQUIRED, 2.1: DONE, 2.2: DONE

ruby_2_1 r50284 merged revision(s) 49867.