[FreeNX-kNX] freenx-server problem : kdeinit4 wont terminate

Tue Oct 18 10:07:52 UTC 2011

Hi all,

I did some workaround to achieve a "quick and dirty" fix to this problem.
It assumes that a zombie session is composed of a single kded4 process 
that stays alone, and that this situation will never appear in another 
situation (I'm not sure of that, but it seems to be true).

The patch is a bash script that runs every our thanks to a cron job. The 
script cleans the remaining sessions based on above assumptions. It also 
sends once a day a digest email, but this can be removed.

First below is the bash script (I named it "cleansession", but you can 
choose what you want as long as you also change it in the crontab). I 
prefixed all things that shall be set before using by a "TBS:" string. ;-)

------------------------------------------------------------------------------------------------------------------------------------------------
#!/bin/bash

#defining log file path & name and redirecting stdout to the log file
LOGFILE=/var/log/cleansession.log
exec >> $LOGFILE

#defining digest mail subject
MAILSUB="TBS:YOU OWN MAIL SUBJECT"

echo -e "\n`date` ==> Running clean up of sessions\n"

####################################################
# SEARCHING AND KILLING ZOMBIE SESSIONS
####################################################

#going through user IDs
for i in {TBS:FIRST_USER_ID..TBS:LAST_USER_ID}  #example {1000..1999}
do
        if [ `pgrep -c -u $i` -ge 1 ]   #if the user has running processes
        then
                if [ `pgrep -l -u $i | grep -v "kded4" | wc -l` -eq 0 ] 
#if running processes are only "kded4" instances, i.e. sessions are zombie
                then
                SESS_NUMBER=`pgrep -l -u $i | wc -l`    #count number of 
zombie sessions
                        echo "[ACT] $i has only kded4 process(es) : 
$SESS_NUMBER session(s) open"
                        echo -n "Executing ... pkill -9 -u $i ... "
                        if pkill -9 -u $i       #try to kill zombie 
sessions : if it successes ...
                        then
                                echo "Done successfully"        #... job 
is done else ...
                        else
                                echo "Error during execution [!E!]" #... 
log the error
                        fi
                fi
        fi

done

echo -e "\n ==> End of cleanup"

####################################################
# SENDING DIGEST EMAIL ONCE A DAY
####################################################

if [ `date +%H` -eq 0 ] #if this is the first cleaning of the day
then
        NBERR=`cat $LOGFILE | grep -F "!E!" | wc -l`    #count number of 
errors that happened
        if [ $NBERR -ge 1 ]     #if some errors happened
        then
                MAILSUB="$MAILSUB : $NBERR errors"      #add error number 
in the mail subject
        fi
        if cat $LOGFILE | grep -Ev "(==>)|(^$)" | mailx -E -s "$MAILSUB" 
TBS:THE_RECEIVER_MAIL_ADDRESS  #create the digest and try to send it ; if 
email sending successes ...
        then
                rm $LOGFILE     #clear log file else ...
        else
                echo "[!!E!!] Digest mail hasn't been sent"     #... log 
the error
        fi
fi
------------------------------------------------------------------------------------------------------------------------------------------------

And now the cronjob to be added in crontab (you have to customize it with 
the script path & name you chose) :

------------------------------------------------------------------------------------------------------------------------------------------------
0 * * * * /usr/local/bin/cleansession
------------------------------------------------------------------------------------------------------------------------------------------------

Hope it can help.

Kind regards,
Matthieu

freenx-knx-bounces at kde.org wrote on 17/10/2011 08:48:25:

> From: chris
> To: freenx-knx at kde.org
> Date: 17/10/2011 08:48
> Subject: Re: [FreeNX-kNX] freenx-server problem : kdeinit4 wont 
terminate
> Sent by: freenx-knx-bounces at kde.org
> 
> 
> freenx-knx-bounces at kde.org wrote on 14/10/2011 12:58:42:
> 
> > Hi all,
> > 
> > I have currently a problem using freenx-server. When the session is 
closed 
> > by using the top right closing button of the client window, then click 

> > "End", the "kdeinit4" process doesn't terminate and stays alive. As en 

> 
> Do you mean the session's kded4, which was SPAWNED by kdeinit, 
> doesn't termintate when you 
> end your NX session by using the NX window's X button or Ctrl-Alt-T 
> and 
> then choosing "Terminate" from the "Disconnect Terminate Cancel" dialog 
??? 
> 
> If so, you are probably noticing accumulating orphan kded4 processes, 
> one for each session you close in this manner ???? 
> 
> > effect, the NX session terminates correctly but the pts session stays.
> > But if the session is closed through the KDE menu ("Leave" then 
"logout"), 
> > everything terminates correctly and there is no more remaining 
process.
> 
> yup 
> 
> > 
> > The system is as follow :
> > Server : FreeNX server 0.7.3 on a Kubuntu 11.04
> > Client : NoMachine client 3.4.0-7 on Windows XP
> > 
> > I change the debug level of the NX server to 6, but it 
> > indicates no problem.
> > 
> > Could somebody help ?
> 
> Terminating the X session this way causes kded4 to 
> lock up and refuse to close on a SIGHUP or SIGTERM 
> 
> The various running kde processes report :- 
> 
>          "Fatal IO error: client killed" 
> 
> kdeinit4 then responds by trying to clean up its processes :- 
> 
>         kdeinit4: sending SIGHUP to children. 
> and 
>         kdeinit4: sending SIGTERM to children. 
> and 
> then it terminates itself 
> but 
> this has no effect on kded4, which now will only end 
> on a SIGKILL. 
> 
> 
> From debug it looks like it's left waiting on a mutex or 
> something . . . 
> 
> QWaitCondition::wait(QMutex*,unsigned long)()from/usr/lib/libQtCore.so.4 

> 
> 
> On the other hand, if you end ksmserver via kicker 
> leaving X running whilst kde sorts itself out, then kded4 
> ends when it's told to. 
> 
> 
> So far most reported problems with kded4 seem to be 
> include 100%CPU utilization running away with the 
> machine, in comparison with which this problem is fairly 
> benign, but it's still annoying htey haven't got around 
> to fixing it yet. 
> 
> In the short term your options include:- 
> 
> 1/ telling your users to log out via kicker 
> 2/ just clearing up the orphan processes every so often 
> 3/ adding a command file to the kde shutdown scripts 
>         e.g. create the following 3 line file 
>            /usr/shutdown/kded4.sh 
> as 
> 
> 
> #! /bin/sh 
> # 
> pkill -9 kded4 
> 
> 
> then set the file to execute 
> 
>         sudo chmod 555 /usr/shutdown/kded4.sh 
> 
> That's for Opensuse. 
> It might need to be elsewhere on planet KUbuntu. 
> 
> kde will then kill ALL YOUR USENAME'S instances of 
> kded4 whenever you end a session. 
> 
> > 
> > Thanks in advance,
> > Matthieu
> > 
> 
> Note:- This is a kde problem not a FreeNX problem 
> ________________________________________________________________
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> 
> 
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> 
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> 
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