bug#54458: 27.2; erc-dcc-get: Re-entering top level after C stack overflow

[Eli Zaretskii]

> From: Fernando de Morais <fernandodemorais.jf@gmail.com>
> Cc: jp@neverwas.me,  54458@debbugs.gnu.org,  bandali@gnu.org
> Date: Sun, 27 Mar 2022 14:34:43 -0300
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > can you rebuild without stripping, or download and install the missing
> > debug symbols somewhere?  Then repeat the experiment and post the
> > backtrace.
> >
> > Thanks.
> 
> Hello Eli,
> 
> I rebuilt Emacs from ``emacs-27'' branch, following the DEBUG guide that
> came in etc folder.
> 
> I hope the logs can now be more useful.

Thanks.  This surely looks like either infinite recursion, or a very
deep recursion that triggers GC, and GC exhausts the stack (since GC
itself is deeply recursive).

It would help if you could reproduce the problem again, this time when
running Emacs under GDB to begin with.  When Emacs segfaults, please
do

  (gdb) source /path/to/emacs/src/.gdbinit
  (gdb) xbacktrace

(replace /path/to/emacs/src with the directory where you have the
Emacs source tree).  The last command will show the Lisp interpreter
nacktrace, which will make it easier to understand where the recursion
happens in Lisp.