bug#39962: 27.0.90; Crash in Emacs 27.0.90

[Pip Cet]

On Tue, Mar 17, 2020 at 3:29 AM Pieter van Oostrum
<pieter-l@vanoostrum.org> wrote:
> Pip Cet <pipcet@gmail.com> writes:
>
> > Another thing we could try is poisoning the memory area used by a
> > vector when we put it on the free list. Something like the attached
> > patch might work.
>
> I made a new compile with the patch 
> 0001-poison-memory-of-vectors-put-on-the-free-list.patch applied and also the 
> latest 0001-Don-t-collect-reachable-killed-buffers-during-GC.patch (from 
> message ID 
> <CAOqdjBfeL-T8grB+sW+jLoW-JX8Y0siFTzG1q0o+Skc+sKvtSQ@mail.gmail.com>) applied.

Thanks!

> (gdb) f 3
> #3  0x000000010023cdc5 in marker_position (marker=XIL(0x12590f575))
>     at marker.c:691
> 691       register struct Lisp_Marker *m = XMARKER (marker);
> (gdb) p marker
> $1 = XIL(0x12590f575)
> (gdb) xtype
> Lisp_Vectorlike
> PVEC_NORMAL_VECTOR
> (gdb) p m
> $2 = (struct Lisp_Marker *) 0x7ffeefbe92d0

m has not been set; it would have been set to 0x12590f570; can you
print out the memory at that address? (x/32gx 0x12590f570)