bug#58956: mark_object, mark_objects(?) crash

[Eli Zaretskii <eliz@gnu.org>]

> Cc: 58956@debbugs.gnu.org, 1017711@bugs.debian.org
> Date: Thu, 3 Nov 2022 04:00:46 +0100
> From: Vincent Lefevre <vincent@vinc17.net>
> 
> On 2022-11-02 14:24:51 +0200, Eli Zaretskii wrote:
> > Signal 1 is SIGHUP, AFAIU.  Why should Emacs receive SIGHUP in the
> > middle of GC, I have no idea.  Maybe ask the user what was he doing at
> > that time.  E.g., could that be a remote Emacs session?
> 
> No, it is on my local machine.

So how come Emacs gets a SIGHUP?  This is the crucial detail that is
missing here.  Basically, if SIGHUP is delivered to Emacs, Emacs is
supposed to die a violent death.

> I run emacs, and quit it immediately. The generation of the core dump
> is almost 100% reproducible. Ditto with "emacs -nw".

Wait, you mean the crash is during exiting Emacs?  That could mean
Emacs receives some input event when it's half-way through the
shutdown process, and the input descriptor is already closed.

But the backtrace you posted shows SIGHUP during GC, which is AFAIU a
very different case.