bug#48252: Crashes continue ...

[Eli Zaretskii]

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> From: andrei.elkin@pp.inet.fi
> Date: Fri, 29 Oct 2021 20:19:40 +0300
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> From: andrei.elkin@pp.inet.fi
> >> Cc: 48252@debbugs.gnu.org
> >> Date: Fri, 29 Oct 2021 18:08:03 +0300
> >> 
> >> Eli Zaretskii <eliz@gnu.org> writes:
> >> 
> >> >> From: andrei.elkin@pp.inet.fi
> >> >> Date: Thu, 28 Oct 2021 16:38:00 +0300
> >> >> 
> >> >> ...and what maybe is better that the most recent stack, below, is much 
> >> >> shorter.
> >> >> And I am leaving it alive in case there will be interest or just further
> >> >> instruction for me.
> >> >
> >> > Please invoke xbacktrace and post the results.  (If GDB says it
> >> > doesn't know that command, say "source /path/to/emacs/src/.gdbinit"
> >> > first.)
> >> 
> >> (gdb) xbacktrace 
> >> "command-error-default-function" (0xffffd448)
> >> "apply" (0xffffd618)
> >> 0xea3950a0 PVEC_COMPILED
> >
> > Is that all?  It should be a lot longer.
> 
> That's all though bt still produces the same stack.

Then you will have to do it manually.  For each stack frame N that
shows a call to Ffuncall, like this:

  #7  0x00005555557be66d in Ffuncall (nargs=4, args=0x7fffffffd440) at 
eval.c:3068

please do:

  (gdb) frame N
  (gdb) print args[0]
  (gdb) xtype

The last command will usually say "Lisp_Symbol", in which case follow
it with

  (gdb) xsymbol

Also, try this:

  (gdb) frame 17
  (gdb) p data
  (gdb) xtype

The last command will probably say "Lisp_Cons", in which case please
show its cells using the xcar and xcdr commands.

In general, what I see is that some command signaled an error, and the
error data includes some invalid Lisp object.  The challenge is to
find that command and understand what kind of invalid object it
generates.