From: ts <decoux@...>
Date: 2004-10-16T22:06:38+09:00
Subject: Re: [BUG] segfault in ruby-1.8.2p2

>>>>> "B" == Brian Candler <B.Candler@pobox.com> writes:

B> #4  0xbfbfffac in ?? ()

 Well, what you don't see is that ruby is in scope_dup(tag->scope)

B> #5  0x2809127f in eval () from /usr/local/lib/libruby18.so.18

[...]

B> #78 0x280866fe in ruby_exec () from /usr/local/lib/libruby18.so.18

 here is the problem : one thread has a reference to ruby_exec() in its
 stack and more precisely to _tag which is created in ruby_exec()

 This is precisely when ruby use this value for the call to scope_dup()
 that it crash.

 The reason is that the main thread has leaved ruby_exec() and ruby is
 actually executing rb_thread_wait_other_threads() in ruby_cleanup()

 When it try to reference tag, in another thread, it make reference to a
 variable which don't exist on the stack : this is why it crash



Guy Decoux