bug#48433: 28.0.50; Emacs Core Dump when trying to visit file

[Eli Zaretskii]

> Cc: 48433@debbugs.gnu.org, acm@muc.de
> From: Sébastien Le Callonnec <sebastien@weblogism.com>
> Date: Sat, 15 May 2021 11:10:38 +0100
> 
> > Thanks, but can you also provide a Lisp backtrace, by invoking
> > "xbacktrace" from GDB?  That command is defined in src/.gdbinit.
> > 
> 
> I am not having much luck there:
> 
> (gdb) xbacktrace
> 'backtrace_top' has unknown return type; cast the call to its declared
> return type

How did you compile Emacs?  Please compile with -g3 on the compiler
command line.

> This seems to isolate the issue to `read_minibuf_unwind`, which is part
> of the changeset of the commit I bisected to.

That was clear before, what is not clear is _where_ in
read_minibuf_unwind it happens, and why.  That's a very large
function.