bug#74981: 29.4; X11 crash when minibuffer text scale is increased greatly

[Joseph Turner]

Eli Zaretskii <eliz@gnu.org> writes:

>> Date: Thu, 19 Dec 2024 14:06:59 -0800
>> From:  Joseph Turner via "Bug reports for GNU Emacs,
>>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
>> 
>> Tested on two window managers, exwm and dwm, with emacs -Q:
>> 
>> Open the minibuffer, e.g., with M-x eval-expression.  Run
>> text-scale-adjust with C-x C-=. The minibuffer text gets
>> bigger. Repeatedly press C-= until X11 crashes, bringing you back to the
>> login prompt.
>
> Thanks.
>
> I can't reproduce this, but I'm not on X11.  What happens here is that
> after many "C-x C-= C-=" presses, the minibuffer (whose contents
> becomes illegible long before that) starts blinking, and I need to C-g
> out of it (or C-x C-c to kill Emacs).  This seems harmless enough,
> since the enlarged font is not useful past the point where the
> minibuffer no longer shows the minibuffer text.
>
> Can you run this under GDB, and when Emacs crashes, type
>
>   (gdb) thread apply all bt
>
> and post everything GDB produces as result?

Since the entire X11 session crashes, I'm not sure how to do this.

Please advise.  Thanks!

Joseph