[Pkg-libvirt-maintainers] Bug#943708: virt-manager crashes: python3: ../../src/xcb_io.c:263: poll_for_event: Assertion `!xcb_xlib_threads_sequence_lost' failed.

[Brad]

Package: virt-manager
Version: 1:2.2.1-2
Severity: normal

virt-manager crashes on me quite often. It's been doing this for the last year or so, but never before then. I think it was when I first upgraded to 2.0.0, but not sure.

Today I upgraded from 1:2.0.0-3 to 1:2.2.1-2 to see if it was still crashing and indeed it is.

When run with --debug, I get this output on a crash:

[xcb] Unknown sequence number while processing queue
[xcb] Most likely this is a multi-threaded client and XInitThreads has not been called
[xcb] Aborting, sorry about that.
python3: ../../src/xcb_io.c:263: poll_for_event: Assertion `!xcb_xlib_threads_sequence_lost' failed.
Aborted

Most often happens when there is a visual change on the screen induced by:
	Right-clicking to open a menu.
	Clicking on a window to move it.
	Highlighting and selecting text.
	Opening an image file to display.

There is no question in my mind that it's being triggered by user activity, as it always crashes when I do something. It happens pretty randomly about twice a day with 4-8 hours of usage. I don't think there's anything specific I can do to reliably reproduce it.




-- System Information:
Debian Release: 10.0
  APT prefers unstable
  APT policy: (500, 'unstable'), (500, 'testing'), (500, 'stable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.19.0-5-amd64 (SMP w/4 CPU cores)
Kernel taint flags: TAINT_WARN
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE= (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages virt-manager depends on:
ii  dconf-gsettings-backend [gsettings-backend]  0.30.1-2
ii  gir1.2-gtk-3.0                               3.24.5-1
ii  gir1.2-gtk-vnc-2.0                           0.9.0-1.1
ii  gir1.2-gtksource-4                           4.4.0-1
ii  gir1.2-libosinfo-1.0                         1.2.0-1
ii  gir1.2-libvirt-glib-1.0                      1.0.0-1
ii  gir1.2-vte-2.91                              0.54.2-2
ii  librsvg2-common                              2.44.10-2.1
ii  python3                                      3.7.3-1
ii  python3-dbus                                 1.2.8-3
ii  python3-gi                                   3.30.4-1
ii  python3-gi-cairo                             3.30.4-1
ii  python3-libvirt                              5.0.0-1
ii  virtinst                                     1:2.2.1-2

Versions of packages virt-manager recommends:
ii  gir1.2-spiceclientglib-2.0  0.35-2
ii  gir1.2-spiceclientgtk-3.0   0.35-2
ii  libvirt-daemon-system       5.0.0-3

Versions of packages virt-manager suggests:
ii  gir1.2-secret-1            0.18.7-1
ii  gnome-keyring              3.28.2-5
ii  ksshaskpass [ssh-askpass]  4:5.14.5-1
pn  python3-guestfs            <none>
ii  virt-viewer                7.0-2

-- debconf-show failed