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

From: Eli Zaretskii <[email-masked]>
Date: Fri, 20 Dec 2024 08:55:38 +0200

> 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" <[email-masked]>
> 
> 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?