[ruby-core:44579] [ruby-trunk - Bug #6341] SIGSEGV: Thread.new { fork { GC.start } }.join

Issue #6341 has been updated by naruse (Yui NARUSE).


kosaki (Motohiro KOSAKI) wrote:
> On Mon, Apr 23, 2012 at 11:17 PM, Yusuke Endoh <[e-mail]> wrote:
>  > I suggest to make Kernel#fork raise a NotImplementedError on NetBSD
>  > 5.0+.
>  > Fortunately, the tests already have a guard for NotImplementedError
>  > because there is a supported platform that does not support
>  > Kernel#fork (you know, windows).
>  > Even on the platform, SEGV is not allowed, in principle.
>  
>  No. it works if user don't use threads. So, one option is, fork after
>  thread.new raise an exception on all platform.

It is wrong.
Ruby 1.9 makes timer thread even if there is only the main thread.
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Bug #6341: SIGSEGV: Thread.new { fork { GC.start } }.join
https://bugs.ruby-lang.org/issues/6341#change-26147

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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