Debian Bug report logs - #984593
libmutter-7-0: gnome-shell segfaults because monitor_mode contains null pointer.

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Package: libmutter-7-0; Maintainer for libmutter-7-0 is Debian GNOME Maintainers <[email protected]>; Source for libmutter-7-0 is src:mutter (PTS, buildd, popcon).

Affects: gnome-shell

Reported by: Bernhard Übelacker <[email protected]>

Date: Fri, 5 Mar 2021 15:06:01 UTC

Severity: normal

Found in version mutter/3.38.3-2

Done: Jeremy Bícha <[email protected]>

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Report forwarded to [email protected], [email protected], Debian GNOME Maintainers <[email protected]>:
Bug#984593; Package libmutter-7-0. (Fri, 05 Mar 2021 15:06:03 GMT) (full text, mbox, link).


Acknowledgement sent to Bernhard Übelacker <[email protected]>:
New Bug report received and forwarded. Copy sent to [email protected], Debian GNOME Maintainers <[email protected]>. (Fri, 05 Mar 2021 15:06:03 GMT) (full text, mbox, link).


Message #5 received at [email protected] (full text, mbox, reply):

From: Bernhard Übelacker <[email protected]>
To: Debian Bug Tracking System <[email protected]>
Subject: libmutter-7-0: gnome-shell segfaults because monitor_mode contains null pointer.
Date: Fri, 5 Mar 2021 16:02:56 +0100
[Message part 1 (text/plain, inline)]
Package: libmutter-7-0
Version: 3.38.3-2
Severity: normal
X-Debbugs-Cc: [email protected]

Dear Maintainer,
I tried to replicate #982572, therefore
setup a qemu VM with two qxl devices [1].

This is currently running a kernel 5.2 due to #983934.

Inside I have trouble with mouse input,
therefore activated remote access by keyboard.
(Unfortunately can just access one of the
two screens with this method.)

On that screen I did some resolution changes and
window moves, then gnome-shell crashed.
I have not yet tried to reproduce this or cannot
say if this happens because of this special setup.
Found also no other down- or any upstream bug about this.

It seems that we get in [3] a nullpointer for "monitor_mode",
that gets dereferenced later.

In [2] are the last frames of the backtrace, complete
in attached file.

Kind regards,
Bernhard


[3] https://sources.debian.org/src/mutter/3.38.3-3/src/backends/meta-renderer.c/#L228

[2]
    (gdb) bt
    #0  meta_monitor_mode_foreach_crtc (monitor=monitor@entry=0x55c936bd45a0, mode=0x0, func=func@entry=0x7fbadddaf010 <collect_views>, user_data=user_data@entry=0x7fff8032e9e0, error=error@entry=0x0) at ../src/backends/meta-monitor.c:1912
    #1  0x00007fbadddaefe5 in meta_renderer_real_get_views_for_monitor (renderer=<optimized out>, monitor=0x55c936bd45a0) at ../src/backends/meta-renderer.c:228
    #2  0x00007fbadde3190f in is_redraw_queued (monitor_src=0x7fbacc039150) at ../src/backends/meta-screen-cast-monitor-stream-src.c:210
    #3  sync_cursor_state (monitor_src=0x7fbacc039150) at ../src/backends/meta-screen-cast-monitor-stream-src.c:228
    #4  0x00007fbadeab80a2 in g_closure_invoke (closure=0x55c9376dd460, return_value=return_value@entry=0x0, n_param_values=1, param_values=param_values@entry=0x7fff8032ebd0, invocation_hint=invocation_hint@entry=0x7fff8032eb50) at ../../../gobject/gclosure.c:810
    #5  0x00007fbadeaca602 in signal_emit_unlocked_R (node=node@entry=0x55c936648d40, detail=detail@entry=0, instance=instance@entry=0x7fbac0002280, emission_return=emission_return@entry=0x0, instance_and_params=instance_and_params@entry=0x7fff8032ebd0) at ../../../gobject/gsignal.c:3809
    #6  0x00007fbadead06cf in g_signal_emit_valist (instance=<optimized out>, signal_id=<optimized out>, detail=<optimized out>, var_args=var_args@entry=0x7fff8032ed50) at ../../../gobject/gsignal.c:3495
    #7  0x00007fbadead0c3f in g_signal_emit (instance=<optimized out>, signal_id=<optimized out>, detail=<optimized out>) at ../../../gobject/gsignal.c:3551
    #8  0x00007fbadde4cdba in meta_wayland_pointer_set_focus (pointer=0x55c936be7820, surface=<optimized out>) at ../src/wayland/meta-wayland-pointer.c:973
    #9  0x00007fbadde4d40d in repick_for_event (pointer=0x55c936be7820, for_event=<optimized out>) at ../src/wayland/meta-wayland-pointer.c:640
    ...

[1] -spice port=5930,addr=$LOCALIP,disable-ticketing -device qxl-vga,id=video0,ram_size=67108864,vram_size=67108864,vram64_size_mb=0,vgamem_mb=16,max_outputs=1 -device qxl,id=video1,ram_size=67108864,vram_size=67108864,vram64_size_mb=0,vgamem_mb=16,max_outputs=1




-- System Information:
Debian Release: bullseye/sid
  APT prefers testing-debug
  APT policy: (500, 'testing-debug'), (500, 'proposed-updates-debug'), (500, 'testing')
Architecture: amd64 (x86_64)

Kernel: Linux 5.2.0-3-amd64 (SMP w/4 CPU threads)
Locale: LANG=de_DE.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages libmutter-7-0 depends on:
ii  adwaita-icon-theme         3.38.0-1
ii  gsettings-desktop-schemas  3.38.0-2
ii  libatk1.0-0                2.36.0-2
ii  libc6                      2.31-9
ii  libcairo-gobject2          1.16.0-5
ii  libcairo2                  1.16.0-5
ii  libcanberra0               0.30-7
ii  libdrm2                    2.4.104-1
ii  libegl1                    1.3.2-1
ii  libfontconfig1             2.13.1-4.2
ii  libfribidi0                1.0.8-2
ii  libgbm1                    20.3.4-1
ii  libgdk-pixbuf-2.0-0        2.42.2+dfsg-1
ii  libgl1                     1.3.2-1
ii  libglib2.0-0               2.66.7-1
ii  libgnome-desktop-3-19      3.38.4-1
ii  libgraphene-1.0-0          1.10.4+dfsg1-1
ii  libgtk-3-0                 3.24.24-1
ii  libgudev-1.0-0             234-1
ii  libice6                    2:1.0.10-1
ii  libinput10                 1.16.4-3
ii  libjson-glib-1.0-0         1.6.2-1
ii  libpango-1.0-0             1.46.2-3
ii  libpangocairo-1.0-0        1.46.2-3
ii  libpangoft2-1.0-0          1.46.2-3
ii  libpipewire-0.3-0          0.3.19-4
ii  libsm6                     2:1.2.3-1
ii  libstartup-notification0   0.12-6+b1
ii  libsystemd0                247.3-1
ii  libudev1                   247.3-1
ii  libwacom2                  1.8-2
ii  libwayland-server0         1.18.0-2~exp1.1
ii  libx11-6                   2:1.7.0-2
ii  libx11-xcb1                2:1.7.0-2
ii  libxau6                    1:1.0.9-1
ii  libxcb-randr0              1.14-3
ii  libxcb-res0                1.14-3
ii  libxcb1                    1.14-3
ii  libxcomposite1             1:0.4.5-1
ii  libxcursor1                1:1.2.0-2
ii  libxdamage1                1:1.1.5-2
ii  libxext6                   2:1.3.3-1.1
ii  libxfixes3                 1:5.0.3-2
ii  libxi6                     2:1.7.10-1
ii  libxinerama1               2:1.1.4-2
ii  libxkbcommon-x11-0         1.0.3-2
ii  libxkbcommon0              1.0.3-2
ii  libxkbfile1                1:1.1.0-1
ii  libxrandr2                 2:1.5.1-1
ii  libxtst6                   2:1.2.3-1
ii  mutter-common              3.38.3-2

libmutter-7-0 recommends no packages.

libmutter-7-0 suggests no packages.

Versions of packages libmutter-7-0 is related to:
ii  libegl-mesa0 [libegl-vendor]  20.3.4-1
ii  libgl1-mesa-dri               20.3.4-1
ii  libglx-mesa0 [libglx-vendor]  20.3.4-1

-- no debconf information
Thank you for using reportbug
[debugging.txt (text/plain, attachment)]

Added indication that 984593 affects gnome-shell Request was from Bernhard Übelacker <[email protected]> to [email protected]. (Fri, 05 Mar 2021 15:18:03 GMT) (full text, mbox, link).


Reply sent to Jeremy Bícha <[email protected]>:
You have taken responsibility. (Tue, 29 Apr 2025 00:09:02 GMT) (full text, mbox, link).


Notification sent to Bernhard Übelacker <[email protected]>:
Bug acknowledged by developer. (Tue, 29 Apr 2025 00:09:03 GMT) (full text, mbox, link).


Message #12 received at [email protected] (full text, mbox, reply):

From: Jeremy Bícha <[email protected]>
To: [email protected]
Subject: Re: libmutter-7-0: gnome-shell segfaults because monitor_mode contains null pointer.
Date: Mon, 28 Apr 2025 20:04:43 -0400
There have been many changes to Debian since this bug was originally
reported. If you are still experiencing this issue with Debian 12 (or
with Testing or Unstable), please report a new bug.

Thank you,
Jeremy Bícha



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