Xpra: Ticket #1456: Server crashes on launching application (inconsistently)

This does not happen every time I launch thunderbird, but sometimes. The following error shows up in server's log before the crash:

2017-03-01 21:23:10,833 started command 'thunderbird' with pid 7119
[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.

I was able to revive the session with xpra upgrade afterwards

Wed, 01 Mar 2017 18:32:21 GMT - Antoine Martin: status changed; milestone set

I have seen this very occasionally and indicates a bug in xpra. Unfortunately, I have not been able to reproduce it reliably. If you can reproduce it, please attach the end of the server's "-d all" log.

Wed, 01 Mar 2017 23:22:02 GMT - psycho_zs: attachment set

Wed, 01 Mar 2017 23:23:50 GMT - psycho_zs:

Attached last 1k lines of log. With -d all the only new info at the moment of the crash is the python error.

Wed, 01 Mar 2017 23:27:19 GMT - psycho_zs: attachment set

Wed, 01 Mar 2017 23:28:18 GMT - psycho_zs:

Another crash upon connecting, with IO error 11. X server is alive and session can be restored with xpra upgrade

Wed, 01 Mar 2017 23:31:03 GMT - psycho_zs:

...also I can not seem to launch xpra on server anymore, it outputs this:

$ xpra start :100
using systemd-run to wrap 'start' server command
'systemd-run' '--description' 'xpra-start' '--scope' '--user' '/usr/bin/xpra' 'start' ':100' '--systemd-run=no'
Failed to create bus connection: No such file or directory

Remote start works though.

Thu, 02 Mar 2017 04:26:52 GMT - Antoine Martin:

Lots of goodies in those log samples. What distro is this? What exact command lines?

Here's a list of significant events leading up to this last crash:

It would save me a lot of time to know that I only really care about the last few entries!

Thu, 02 Mar 2017 05:15:27 GMT - psycho_zs:

This was done on Current Debian testing, 64bit, xpra 2.0 r15180. Thunderbird with firetray extension. Server launched with remote xpra start ssh:...:100 -d all At some point it was re-launched after crash with the same X session by xpra upgrade :100 locally on the server, if I remember correctly. (local xpra start does not work).

Thu, 02 Mar 2017 12:29:45 GMT - Antoine Martin: priority changed

I have seen the crash - not sure how to reproduce it reliably yet. Hints would be welcome.

Thu, 02 Mar 2017 17:23:26 GMT - Antoine Martin: owner, status changed

@psycho_zs: I am unable to make it crash now that I am ready to investigate it :( I've stopped and restarted thunderbird dozens of times using xpra control :3 start thunderbird. Then I hit a different bug when running debian stretch: we seem to be crashing handling the initial info request, it could be the same bug.

If you can reproduce the thunderbird one easily, can you try:

Fri, 03 Mar 2017 15:17:20 GMT - Antoine Martin:

Identified the initial connection problem - hopefully this is the last one: #1430. The patch suggested in comment:8 should avoid causing the crash so easily, but the correct fix will prevent any "info" query from causing crashes.

Fri, 03 Mar 2017 16:21:56 GMT - Antoine Martin:

Bug squashed, see ticket:1430#comment:4. This affected both 1.0.x and trunk.

@psycho_zs: I would really appreciate if you could try to break it again now that I have committed those fixes. I am quite confident the fixes are correct, but there may still be another bug lurking somewhere. To make it easier I have posted updated Debian Stretch beta packages (both trunk and v1.0.4): http://xpra.org/beta.

Fri, 03 Mar 2017 20:51:34 GMT - psycho_zs: attachment set

Fri, 03 Mar 2017 20:52:41 GMT - psycho_zs:

no crash yet, local start works. But server drains CPU when client is connected, attached new error spam.

Sat, 04 Mar 2017 01:48:08 GMT - Antoine Martin: status changed; resolution set

@psycho_zs: great news - thank you, the error you are seeing is unrelated to the crash (was caused by r15205, fixed in r15222)

I am closing this ticket for now, but feel free to re-open it. I will still look into this as part of #1430.

Note: the only way you can hit this codepath is if you have opengl client rendering disabled... which is not recommended.

Sat, 04 Mar 2017 08:04:28 GMT - psycho_zs:

With opengl on I have redraw issues on window resize (just re-checked on Intel, mesa 17.0.0), so I leave that disabled. Will see if I'm able to catch the crash again.

Sat, 23 Jan 2021 05:24:47 GMT - migration script:

this ticket has been moved to: https://github.com/Xpra-org/xpra/issues/1456