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

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

[Joseph Turner via Bug reports for GNU Emacs, the Swiss army knife of text editors]

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.

In GNU Emacs 29.4 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.41,
cairo version 1.18.0)
Windowing system distributor 'The X.Org Foundation', version 11.0.12101007
System Description: Debian GNU/Linux 12 (bookworm)

Configured using:
 'configure
 CONFIG_SHELL=/gnu/store/3jhfhxdf6v5ms10x5zmnl166dh3yhbr1-bash-minimal-5.1.16/bin/bash
 SHELL=/gnu/store/3jhfhxdf6v5ms10x5zmnl166dh3yhbr1-bash-minimal-5.1.16/bin/bash
 --prefix=/gnu/store/9kbz86680cd5m7m7qz5vj7q6kc994rrj-emacs-29.4
 --enable-fast-install --with-cairo --with-modules
 --with-native-compilation=aot --disable-build-details'

Configured features:
ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GPM GSETTINGS HARFBUZZ JPEG
JSON LCMS2 LIBOTF LIBSELINUX LIBSYSTEMD LIBXML2 M17N_FLT MODULES
NATIVE_COMP NOTIFY INOTIFY PDUMPER PNG RSVG SECCOMP SOUND SQLITE3
THREADS TIFF TOOLKIT_SCROLL_BARS TREE_SITTER X11 XDBE XIM XINPUT2 XPM
GTK3 ZLIB

Important settings:
  value of $EMACSLOADPATH: /home/joseph/.guix-extra-profiles/emacs/emacs/share/emacs/site-lisp:/gnu/store/9kbz86680cd5m7m7qz5vj7q6kc994rrj-emacs-29.4/share/emacs/29.4/lisp
  value of $EMACSNATIVELOADPATH: /home/joseph/.guix-extra-profiles/emacs/emacs/lib/emacs/native-site-lisp
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix

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

[Eli Zaretskii]

> 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?

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

[Visuwesh]

[வெள்ளி டிசம்பர் 20, 2024] Eli Zaretskii wrote:

>> 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.

Same here.  Tested on X11 (Xfce) with a Lucid build and master build
(emacs-repository-version 9ddec89e422d0dd6e9069731b8f2dd2c90aa5607).

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

[Joseph Turner via Bug reports for GNU Emacs, the Swiss army knife of text editors]

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

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

[Visuwesh]

[வெள்ளி டிசம்பர் 20, 2024] Joseph Turner via "Bug reports for GNU Emacs, the Swiss army knife of text editors" wrote:

>> 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!

What if you run GDB from a TTY or another X11 session?  You would need
to adjust the DISPLAY variable before the `run' command like this:

    (gdb) set environment DISPLAY :0

[ Replace :0 with whatever the DISPLAY envvar should be, of course.  ]

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

[Eli Zaretskii]

> From: Joseph Turner <joseph@breatheoutbreathe.in>
> Cc: 74981@debbugs.gnu.org, Visuwesh <visuweshm@gmail.com>
> Date: Fri, 20 Dec 2024 18:15:33 -0800
> 
> 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!

I thought by "X11 session crashes" you meant the Emacs session.  If
X11 itself crashes, then I'd first look in the syslog file for any
more detailed information about the crash, and then look for
description of similar X11 crashes on the Internet.  Also, perhaps
upgrading or downgrading your X11 version would fix the problem.

Perhaps you can run X11 itself under GDB, but I don't know how.
Sorry.

One other idea is to change the font you use for the default face,
maybe it's the font which causes the problem.  Cairo could also be the
culprit, so using a different version of Cairo or a non-Cairo build
might solve the problem.

Finally, can I ask why you need to repeatedly press C-= so many times?
is that a real-life need or just a curiosity?