X2Go Bug report logs -
#495
failure to reconnect after abrupt (CTRL-C / SIGINT) termination of x2goclient, corrupt x2go_sessions file?
Reported by: Robert Izzard <izzard@astro.uni-bonn.de>
Date: Fri, 9 May 2014 14:25:01 UTC
Severity: normal
Tags: pending
Found in version 4.0.15-0~847
Fixed in version 4.0.1.16
Done: Mike Gabriel <mike.gabriel@das-netzwerkteam.de>
Bug is archived. No further changes may be made.
Full log
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Package: x2goserver
Version: 4.0.15-0~847
(x2goserver: 4.0.15-0~847~~ubuntu12.04.1 on Ubuntu Linux 12.04.4 LTS kernel 3.8.0-39-generic,
x2goclient: 4.0.15-0~847~ubuntu14.04.1 on Ubuntu Linux 14.04 LTS kernel 3.14.3-031403-generic)
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Please note: I have labelled package x2goserver, but the bug is displayed on x2goclient even though I *think* the bug is in the server somewhere (see below).
Sometimes after an abrupt (e.g. CTRL-C, probably also network
failure or laptop sleep/wake cycle) termination of x2goclient, I
cannot reconnect to the server. I get errors such as the dreaded
"Failure negotiating the session in stage '7'." and "Error: Wrong
version or invalid session authentication cookie." instead.
I am connecting through a proxy using ssh key-based
authentication (using "Try auto-login" with "ssh-agent or default
ssh key" on the proxy, although switching to password made no
difference). I can connect with ssh through the proxy with no
problem. I can *start* an x2go session with no problem. I can
restart a session with no problem *provided I cleanly exit
x2goclient* (e.g. by clicking on the close button on the window).
If I exit x2goclient with a CTRL-C in the terminal, I cannot
connect again. Note that I can connect to an NX session through
the proxy without any problem and this does not have the same
problem when CTRL-C.
Steps to repeat:
1) On the client, open a new desktop on the server using
x2goclient. (I am running KDE but I doubt it matters).
2) On the client, press CTRL-C to stop x2goclient.
3) On the client, try to reconnect -- it fails with errors (which
are very hard to copy-paste as they go so fast, this is a bug in
the GUI):
------------------------
NXPROXY - Version 3.5.0
Copyright (C) 2001, 2010 NoMachine.
See http://www.nomachine.com/ for more information.
Info: Proxy running in client mode with pid '7219'.
Session: Starting session at 'Thu May 8 17:33:51 2014'.
Info: Connecting to remote host 'localhost:31007'.
Info: Connection to remote proxy 'localhost:31007' established.
Error: The remote NX proxy closed the connection.
Error: Failure negotiating the session in stage '7'.
Error: Wrong version or invalid session authentication cookie.
Session: Terminating session at 'Thu May 8 17:33:51 2014'.
Session: Session terminated at 'Thu May 8 17:33:51 2014'.
------------------------
At this point the CPU usage of x2goclient jumps to 100% and I
have to kill it (although the GUI continues to respond). This is
just a minor annoyance at the moment.
And in .x2go/SESSION_ID/sessions on the client, similar warnings:
------------------------
Loop: PANIC! No shutdown of proxy link performed by remote proxy.
Loop: PANIC! The remote NX proxy closed the connection.
Loop: PANIC! Failure negotiating the session in stage '7'.
Loop: PANIC! Wrong version or invalid session authentication cookie.
------------------------
The server clearly detects the disconnect in its session.log,
followed by “Display failure detected” errors on attempted
reconnect:
-----------------------
running as X2Go Agent
NXAGENT - Version 3.5.0
Copyright (C) 2001, 2011 NoMachine.
See http://www.nomachine.com/ for more information.
Info: Agent running with pid '17414'.
Session: Starting session at 'Fri May 9 14:44:26 2014'.
Info: Proxy running in server mode with pid '17414'.
Info: Waiting for connection from 'localhost' on port '30004'.
Info: Accepted connection from '127.0.0.1'.
Info: Connection with remote proxy completed.
Info: Using ADSL link parameters 512/24/1/0.
Info: Using agent parameters 5000/10/50/0/0.
Info: Using cache parameters 4/4096KB/8192KB/8192KB.
Info: Using pack method '16m-png-9' with session
'unix-kde-depth_24'.
Info: Using ZLIB data compression 1/1/32.
Info: Using ZLIB stream compression 4/4.
Info: No suitable cache file found.
Info: Listening to X11 connections on display ':51'.
Info: Established X client connection.
Info: Using shared memory parameters 1/1/1/2048K.
Info: Using alpha channel in render extension.
Info: Not using local device configuration changes.
keyboard file created
SessionPath not defined
Session: Session started at 'Fri May 9 14:44:27 2014'.
Error: Failure reading from the peer proxy.
Error: Connection with remote peer broken.
Error: Please check the state of your network and retry.
Session: Display failure detected at 'Fri May 9 14:44:44 2014'.
Session: Suspending session at 'Fri May 9 14:44:44 2014'.
Session: Session suspended at 'Fri May 9 14:44:44 2014'.
Session: Resuming session at 'Fri May 9 14:45:11 2014'.
Info: Proxy running in server mode with pid '17414'.
Info: Waiting for connection from 'localhost' on port '30004'.
Info: Aborting the procedure due to signal '1'.
Session: Display failure detected at 'Fri May 9 14:45:27 2014'.
Session: Suspending session at 'Fri May 9 14:45:27 2014'.
Session: Session suspended at 'Fri May 9 14:45:27 2014'.
--------------
In .x2go/C-SESSION_ID/session.log on the server, I now have the
following text repeated over and over:
Session: Suspending session at 'Fri May 9 15:08:49 2014'.
[then hundreds or thousands of times, with later timestamps]
The problem appears to be with the file
/var/lib/x2go/x2go_sessions on the server. If I back this up
*before* hitting CTRL-C on the client, then do the CTRL-C, then
reinstate the backup, I can restart the session with no problems.
Clearly this is beyond the ability of a normal user (without root
on the server) and is not really a fix, even if it does work.
It seems that there is a problem with the x2go_sessions file on
the server being corrupted in some way when the remote session is
abruptly disconnected. This is a failure bad enough for me to
stop using x2go and go back to NX.
* Backing up this file all the time is not an option.
* Deleting this file and continuing, as suggested at
http://bugs.x2go.org/cgi-bin/bugreport.cgi?bug=323, is not an
option.
* Note that unlink suggested in
http://bugs.x2go.org/cgi-bin/bugreport.cgi?bug=323, there is no
*server* crash.
* I have tried the other options at
http://bugs.x2go.org/cgi-bin/bugreport.cgi?bug=323, none apply
here (e.g. permissions are fine).
* The action that precipitates the problem is on the *client*
side.
* Note also that the network itself is not at fault: I can
connect from a laptop in the same office (but on a different
subnet) as the server, or from home to the proxy server direct.
Same problem.
* This seems similar to
http://bugs.x2go.org/cgi-bin/bugreport.cgi?bug=101 but the fixes
are more than a year ago and presumably (?) are in the latest
x2goclient already.
* No amount of calls to x2gosuspend-session or x2goresume-session
on the appropriate session makes any difference.
* If I suspend the session with x2gosuspend-session, attempting
to connect *does* set the session into the “Running” state (just
as x2goresume-session). The error seems to occur after this.
Thanks for all your help x2go team, I hope we can fix this
because I'd like to recommend x2go for my colleagues.
Rob
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Last modified:
Wed Dec 4 08:46:23 2024;
Machine Name:
ymir.das-netzwerkteam.de
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