[ruby-core:44608] [ruby-trunk - Bug #6341] SIGSEGV: Thread.new { fork { GC.start } }.join

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


Following patch to NetBSD fixes this issue.
thanks @_enami

Index: pthread.c
===================================================================
RCS file: /cvsroot/src/lib/libpthread/pthread.c,v
retrieving revision 1.133
diff -u -p -r1.133 pthread.c
--- pthread.c   22 Mar 2012 20:01:18 -0000      1.133
+++ pthread.c   24 Apr 2012 16:15:55 -0000
@@ -240,7 +240,7 @@ pthread__fork_callback(void)
        struct __pthread_st *self;

        /* lwpctl state is not copied across fork. */
-       if (_lwp_ctl(LWPCTL_FEATURE_CURCPU, &pthread__first->pt_lwpctl)) {
+       if (_lwp_ctl(LWPCTL_FEATURE_CURCPU, &pthread_self()->pt_lwpctl)) {
                err(1, "_lwp_ctl");
        }
        self = pthread__self();
----------------------------------------
Bug #6341: SIGSEGV: Thread.new { fork { GC.start } }.join
https://bugs.ruby-lang.org/issues/6341#change-26179

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.


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