bug#39962: 27.0.90; Crash in Emacs 27.0.90

[Pieter van Oostrum]

Pieter van Oostrum <pieter-l@vanoostrum.org> writes:

>>> (gdb) p $rsp
>>> $1 = (void *) 0x7ffeef9c9270
>>
>> What is the value of stack_bottom?
>>
> (gdb) p &stack_bottom_variable
> $3 = (void **) 0x7ffeefbff628
>
> (gdb) p current_thread->m_stack_bottom
> $4 = 0x7ffeefbff628 ""
>
>> And how many frames do you have in that backtrace, if you show all of
>> it?
>
> 11567
> #11567 0x00000001001c281e in main (argc=1, argv=0x7ffeefbff660) at 
> emacs.c:2054

(gdb) f 3
#3  0x00000001002b56e7 in mark_overlay (ptr=0x12c489030) at alloc.c:6213
6213          set_vectorlike_marked (&XMARKER (ptr->end)->header);
(gdb) p *ptr
$9 = {
  header = {
    size = -4611686018360274941
  },
  start = XIL(0x12c488fc5),
  end = XIL(0),
  plist = XIL(0x11dc4e263),
  next = 0x12c488f30
}

So the end of the overlay = 0, and the size is negative. Corruption.
Maybe a stray assignment, or error in freeing memory.

This build doesn't have the 
0001-Don-t-collect-reachable-killed-buffers-during-GC.patch applied. I guess 
that patch might help.

-- 
Pieter van Oostrum
www: http://pieter.vanoostrum.org/
PGP key: [8DAE142BE17999C4]