I tried various things including upgrading the guest Linux to Debian 12, and trying master vs 29 branches. Still seeing crashes.

Today I tried configure emacs 29 without "--with-native-compilation". It appears that core dump is no longer happening. Now when I copy on the host, I see the following message in Emacs:

dbus-check-event: D-Bus error: "Not a valid D-Bus event", (dbus-event 10 14)

Backtrace buffer shows the following:

Debugger entered--Lisp error: (dbus-error "Not a valid D-Bus event" (dbus-event 10 14))
signal(dbus-error ("Not a valid D-Bus event" (dbus-event 10 14)))
dbus-check-event((dbus-event 10 14))
dbus-event-bus-name((dbus-event 10 14))
dbus-notice-synchronous-call-errors((dbus-event 10 14) (dbus-error "Not a valid D-Bus event" (dbus-event 10 14)))
run-hook-with-args(dbus-notice-synchronous-call-errors (dbus-event 10 14) (dbus-error "Not a valid D-Bus event" (dbus-event 10 14)))
dbus-handle-event((dbus-event 10 14))
funcall-interactively(dbus-handle-event (dbus-event 10 14))
call-interactively(dbus-handle-event nil [(dbus-event 10 14)])
command-execute(dbus-handle-event nil [(dbus-event 10 14)] t)

On Sun, May 5, 2024 at 10:34 AM Michael Albinus <michael.albinus@gmx.de> wrote:

Eli Zaretskii <eliz@gnu.org> writes:

Hi Eli,

>> I did (setq debug-on-error t), went to https://en.wikipedia.org/wiki/Emacs, randomly selected a fragment
>> "Emacs has over", then did a ctrll+c.
>>
>> Emacs in VirtualBox immediately showed the following:
>>
>> Debugger entered--Lisp error: (wrong-type-argument number-or-marker-p nil)
>> dbus-handle-event((dbus-event "[ \11]*$"))
>> funcall-interactively(dbus-handle-event (dbus-event "[ \11]*$"))
>> call-interactively(dbus-handle-event nil [(dbus-event "[ \11]*$")])
>> command-execute(dbus-handle-event nil [(dbus-event "[ \11]*$")] t)
>
> Does VirtualBox have anything in its documentation that suggests that
> Ctrl-C on the Windows side will cause a D-Bus event on the VM side?
>
> Michael, any idea what is this D-Bus event, and what does it have to
> do with copying into the Windows clipboard?

`dbus-handle-event' is the handler for D-Bus events (sic!). It is
invoked, when a D-Bus event arrives in the keyboard buffer, see
`special-event-map'.

It isn't called explicitly anywhere in Emacs. So I assume that the
"D-Bus" event is pushed to the keyboard buffer by accident, when
communicating with the VirtualBox.

> Thanks.

Best regards, Michael.