Bug 235551

Summary: desktop stops updating in vncviewer until mouse moved
Product: [Fedora] Fedora Reporter: David Timms <dtimms>
Component: vncAssignee: Adam Tkac <atkac>
Status: CLOSED WONTFIX QA Contact: David Lawrence <dkl>
Severity: medium Docs Contact:
Priority: medium    
Version: 6CC: ovasik
Target Milestone: ---   
Target Release: ---   
Hardware: x86_64   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2007-04-10 09:07:33 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Attachments:
Description Flags
/var/log/yum.log listing packages that changed Apr 7 11:00 none

Description David Timms 2007-04-07 04:37:27 UTC 
Description of problem:
A long running Xvnc is responsive, accepts connections, authenticates, and shows
the initial desktop state. Pressing keys into an open gnome-terminal shows that
vncviewer is not receiving screen updates.

Version-Release number of selected component (if applicable):
kernel-2.6.19-1.2895.fc6 * active
kernel-2.6.20-1.2933.fc6 not yet booted!
kernel-devel-2.6.19-1.2895.fc6
kernel-devel-2.6.20-1.2933.fc6
kernel-headers-2.6.20-1.2933.fc6
VMware-server-1.0.1-29996
VMware-server-console-1.0.1-29996
vnc-4.1.2-9.fc6
vnc-server-4.1.2-9.fc6
xorg-x11-server-Xorg-1.1.1-47.5.fc6

How reproducible:
Have seen previously on a different FC3 that was up a long time. May only happen
when uptime is large:
 13:51:18 up 71 days,  2:13,  4 users,  load average: 0.06, 0.09, 0.02

Steps to Reproduce:
1. x86_64 AMD AM2, 2GB ram, vmware-server running 2x 512MB ram vm's
2. 2007-01-26 yum update, rebooted.
3. 2007-03-23 yum update, not rebooted.
4. vnc clients continue to connect and receive screen changes OK.
5. 2007-04-07 yum update, not rebooted.
6. from fc6 update machine, connect to the vncserver.
  
Actual results:
vncviewer across ssh stops receiving screen updates. Moving the mouse, causes
the screen to refresh. Moving the mouse continuously keeps the local vncviewer
screen live to the vncserver.

Expected results:
Normal VNC operation, ie screen getting update as it changes (rather than when
you move the mouse).

Additional info:
Tried from another machine that I was vnced to, same result (this normally works
also).

No errors logged to /var/log/messages on either machine.
 
ps aux|grep -E 'X|vnc'
root      2706  0.0  0.0  65044   476 ?        Ss   Jan26   0:00 /bin/sh
/etc/X11/prefdm -nodaemon
davidt    2959  0.0  1.5  62540 30232 ?        S    Jan26  87:48 Xvnc :1
-desktop davidtdesktop:1 (davidt) -httpd /usr/share/vnc/classes -auth
/home/davidt/.Xauthority -geometry 1024x768 -depth 16 -rfbwait 30000 -rfbauth
/home/davidt/.vnc/passwd -rfbport 5901 -pn
davidt    2980  0.0  0.0  31100   420 ?        Ss   Jan26   0:00
/usr/bin/ssh-agent /usr/bin/dbus-launch --exit-with-session /etc/X11/xinit/Xclients
davidt    2983  0.0  0.0  15132   364 ?        S    Jan26   0:00
/usr/bin/dbus-launch --exit-with-session /etc/X11/xinit/Xclients
root      4719  0.0  0.0  60280   736 pts/4    R+   14:18   0:00 grep -E X|vnc
root     23961  0.0  0.1  77588  2796 tty10    Ss+  Mar23   0:00 /usr/bin/Xorg
:0 -br -audit 0 -auth /var/gdm/:0.Xauth -nolisten tcp vt10
---
top - 14:24:16 up 71 days,  2:46,  4 users,  load average: 0.04, 0.06, 0.02
Tasks: 136 total,   1 running, 135 sleeping,   0 stopped,   0 zombie
Cpu(s):  0.4%us,  0.7%sy,  0.0%ni, 98.5%id,  0.0%wa,  0.4%hi,  0.0%si,  0.0%st
Mem:   1989348k total,  1599772k used,   389576k free,    79860k buffers
Swap:   517380k total,    15656k used,   501724k free,  1100724k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND            
26781 davidt     5 -10  677m 495m 478m S    1 25.5  98:18.08 vmware-vmx         
 2959 davidt    15   0 62540  29m 2528 S    0  1.5  87:49.28 Xvnc               
---
Around the time that this began, I had been trying to get system-config-date to
pickup ntp time, and also performed a yum update.
---
Occurs on all elements eg:
- locked screensaver=black dialog
- gnome-menu: click, wait not result, move mouse, menu appears.
- gnome-terminal: top -d 1  updates only when mouse moved/moving.
Comment 1 David Timms 2007-04-07 05:19:57 UTC 
Created attachment 151907 [details]
/var/log/yum.log listing packages that changed Apr 7 11:00

ps. I had a bit of a go at getting more info with gdb, but no luck. I can leave
the vncserver running a few more days if someone has some ideas about capturing
further relevant information from the faulting system. If not, I expect that
I'll vncserver -kill :1 and restart it vncserver :1, and see if that is enough
to solve it.

A hunch tells me it's due to updating some package on the system. If so,
perhaps the package needs to tell vncserver to restart ?
Comment 2 David Timms 2007-04-08 03:07:46 UTC 
Had another idea, started another vnc, without rebooting or stopping the
problematic one:
# vncserver :2 {root}
$ vncserver :3 {same user}
Both the newly started sessions operate normally when viewed from vncviewer.

What would that suggest ?
Comment 3 Adam Tkac 2007-04-10 09:07:33 UTC 
I don't have any ideas what package could cause this problem :( But restarting
Xvnc is really bad idea. You could updating packages and doing some important
work through Xvnc and restart is bad idea. Looks that this problem will be never
fixed. Thanks for your report, closing.

Regards, -A-