bug#54859: Crash in marking of input events with devices

[Po Lu via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

martin rudalics <rudalics@gmx.at> writes:

> commit c4921d1157a2e3e15b1d779a6bdf768e307275dd
> Author: Po Lu <luangruo@yahoo.com>
> Date:   Fri Apr 8 17:00:37 2022 +0800
>
>     Fix GC marking of input events with devices
>
>     * src/keyboard.c (mark_kboards):
>     * src/pgtkterm.c (mark_pgtkterm): Mark `device' as well.
>
> reliably segfaults my patched version of Emacs.  Note that the line
> numbers of backtraces are not those of master since I have made local
> changes to many of the involved files.  I have not tried to reproduce
> the crashes on master itself because the program to produce the crashes
> uses too many constructs that are not available on master.
>
> A typical crash produced the backtrace below in an -Og -g3 build (-O0
> builds hardly crash that way, if ever).  Note that in my keyboard.c line
> 13102 actually is
>
> 	  mark_object (event->ie.device);
>
> The associated event is always a HELP_EVENT.  If you need further
> information, please tell me.

That was fixed a while back, would you please try with a newer revision?

The problem was that the code to store help events didn't call
EVENT_INIT, so device was left uninitialised.

Thanks.