bug#39962: 27.0.90; Crash in Emacs 27.0.90

[Pip Cet]

On Sat, Mar 7, 2020 at 11:07 AM Pieter van Oostrum
<pieter-l@vanoostrum.org> wrote:
> Eli Zaretskii <eliz@gnu.org> writes:
> >> Date: Sat, 7 Mar 2020 00:55:39 +0100
> >> From: Pieter van Oostrum <pieter@vanoostrum.org>
> >>
> >> I got a segmentation fault in Emacs. I read my email with VM
> >> (Viewmail), and I had a few fairly large mailboxes open when Emacs
> >> crashed. I had a few other cases where it crashed under similar
> >> circumstances, but other cases where it ran without problems.

This is a hunch, but is it possible GC is somehow triggered either on
a secondary thread or in an event handler?

Can you uncomment the definitions of NSTRACE_ENABLED and
NSTRACE_ALL_GROUPS in nsterm.h and post the last few lines produced
that way before a crash? Also, what's the output of "i thr" in gdb
after that crash?