[Spice-devel] help debugging: Assertion `!xcb_xlib_threads_sequence_lost' failed.

[Cole Robinson]

Hi all,

For the past year+ we have had a steady trickle of virt-manager X11
threading crashes. This is the f31 bug I've duped all the other ones
too, but there were a handful that were auto closed by Fedora
end-of-life bug cleanup: https://bugzilla.redhat.com/show_bug.cgi?id=1756065

The message that goes along with this is:

[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.
remote-viewer: xcb_io.c:263: poll_for_event: Assertion
`!xcb_xlib_threads_sequence_lost' failed.
Aborted (core dumped)

That may not apply to all the poll_for_error() bugs but it's most of the
ones I have dug into.

I figured there was some threading issue in virt-manager and I was
mostly ignoring the bugs until I found time to try and diagnose. I'm not
really finding anything in virt-manager though, and some similar issues
make me think maybe this is spice-gtk or something lower.

This user can reproduce the same error with remote-viewer + spice + X11
ssh forwarding: https://bugzilla.redhat.com/show_bug.cgi?id=1758384

This user can reproduce the virt-manager crash multiple times a day, and
it's always when interacting with a spice-gtk console:
https://bugzilla.redhat.com/show_bug.cgi?id=1792576

Anyone have any ideas how to debug this further? What spice-gtk
debugging info would be helpful?

The reporter in the last bug can reproduce regularly and is responsive,
so feel free to just jump in there if you would like to help.

Thanks,
Cole