bug#33091: 27.0.50; Daily+ crashes in auto-save-hook

[Eli Zaretskii]

> From: "Mark A. Hershberger" <mah@everybody.org>
> Cc: 33091@debbugs.gnu.org
> Date: Thu, 18 Oct 2018 16:15:51 -0400
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > IOW, GC segfaults, and then Emacs tries to auto-save the session,
> > which fails.
> >
> > Is it possible that GC hits a stack overflow?  Can you try manually
> > establishing whether that is the case by doing what stack_overflow in
> > sysdep.c does?
> 
> I don't know how to do this. I can follow directions if you can tell me
> what to do, though.

Given the backtrace you show in your report, I believe the commands
below should do that:

  (gdb) frame 13
  (gdb) p/x siginfo->si_addr
  (gdb) p/x stack_bottom
  (gdb) p/x current_thread->stack_top

Stack frame #13 is inside handle_sigsegv, according to your backtrace.