From: "rudolf (r stu3)" <redmine@...>
Date: 2012-04-24T18:27:29+09:00
Subject: [ruby-core:44580] [ruby-trunk - Bug #6341] SIGSEGV: Thread.new { fork { GC.start } }.join


Issue #6341 has been updated by rudolf (r stu3).


I am not sure if the following information are relevant, but I want you to have a complete picture.

I've tried to bring this issue on NetBSD maillist and I've got the following reply (http://mail-index.netbsd.org/current-users/2012/04/22/msg019961.html):
``Memory faults in any malloc implementation are mostly due to bugs is the application (use after free, overwrite end/start allocated buffer, etc).''

When trying with rubinius (yesterday's git snapshot of master branch), it survives without a hiccup.
----------------------------------------
Bug #6341: SIGSEGV: Thread.new { fork { GC.start } }.join
https://bugs.ruby-lang.org/issues/6341#change-26150

Author: rudolf (r stu3)
Status: Feedback
Priority: Low
Assignee: 
Category: core
Target version: 
ruby -v: ruby 1.9.3p196 (2012-04-21) [x86_64-netbsd6.0.]


When running ruby (ruby-lang.org) test suite, I am able to provoke a segfault using a test from bootstraptest/test_thread.rb:
begin
  Thread.new { fork { GC.start } }.join
  pid, status = Process.wait2
  $result = status.success? ? :ok : :ng
rescue NotImplementedError
  $result = :ok
end

It is easy to provoke the problem with this command launched in shell (1-20 times until the problem shows):
$ ruby -e "Thread.new { fork { GC.start } }.join"

Environment:
- NetBSD-6.0_BETA amd64, from 2012/04/21
- ruby_1_9_3 branch, revision 35416 (I've also tried trunk and it has similar problem)
- 8 GB RAM, a lot of free memory, dual-core CPU
- gcc version 4.5.3 (NetBSD nb2 20110806)

Backtrace and "bt full" is available in the attached gdb_session.txt file.


-- 
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