[mythtv-users] Frontend locking up and unable to kill it.

Stephen Worthington stephen_agent at jsw.gen.nz
Thu Jul 11 18:10:01 UTC 2019


On Thu, 11 Jul 2019 10:05:30 -0700, you wrote:

>On Thu, Jul 4, 2019 at 9:27 AM Stephen Worthington <stephen_agent at jsw.gen.nz>
>wrote:
>
>> On Thu, 4 Jul 2019 08:01:48 -0700, you wrote:
>>
>> >> Here is what I did:
>> >top (to find the PID)
>> >sudo kill 1555
>> >top (still running)
>> >sudo kill 1555
>> >top (still running)
>> >sudo kill -9 1555
>> >ps aux | grep mythfrontend (still running)
>> >sudo killall  mythfrontend.re
>> >ps aux | grep mythfrontend (still running)
>> >I believe it was at this point I went downstairs and found the popup
>> asking
>> >if I really wanted to kill the program but with no cursor I was unable to
>> >randomly land on the "Yes" area and it did not respond to a "Y" from the
>> >keyboard. The UI was still interactive and I did a right click on the
>> >mythfrontend tack on the taskbar and said close. The computer was still
>> >acting normally at this time except no cursor. I then went back upstairs
>> to
>> >my remote session.
>> >sudo shutdown now -r
>> >Then I went downstairs to the computer and pressed the power button, which
>> >normally does a graceful shutdown. Nothing happened so then I held the
>> >power button down and the computer turned off.
>> >
>> >So as you can see, I did kill PID twice.
>>
>> OK, so it is not the double kill problem.
>>
>> If you need to find the cursor, you can do Ctrl-Alt-T to open a
>> terminal window and the cursor will show up when it is over that
>> window.  So you move the window until it is lined up above the thing
>> you want to click, and then move the cursor straight down off that
>> window until you think you are in the right place and click.  With
>> only one degree of freedom, it usually does not take too many tries to
>> hit the right location.
>>
>> Another thing worth trying is to shut down and restart X - if
>> mythfrontend is locked up waiting for something in X, that should
>> unlock it.  If you are running lightdm as the display manager, then
>> you can do that with:
>>
>> sudo systemctl restart lightdm
>>
>> I do not know if that works with gdm, as I have had to switch to
>> lightdm on my 18.04 systems in order to get around a gdm problem that
>> makes x11vnc not work.  It is easy to switch from gdm to lightdm -
>> just install the lightdm package and reboot.
>>
>> It is also a good idea to have a terminal window open in the
>> background anyway, as with some of the mythfrontend problems, it does
>> a broadcast crash message (usually an "Assert failed" message) that
>> gets displayed on all open terminals.
>>
>> >I was under the impression that Ubuntu 18.04 would break my LIRC code and
>> >become another project to get the system working again. I ran Mythbuntu
>> >8.04 until just this year and never had the problems I have had with the
>> >latest install. I thought I had it all fixed but then these two lock ups
>> >happened. Very frustrating.
>>
>> Yes, the latest mythfrontend does have a couple of ways of crashing.
>> But I have not seen it lock up as you are getting.  It also has lots
>> of nice new things too, and more coming.
>>
>> It was the change to kernel drivers and devinput in 14.04? 16.04? that
>> really broke LIRC setups, but you will have already met that.  So yes,
>> the LIRC code as installed by the 18.04 package is badly broken, but
>> you just need to run this script from my web server to fix that:
>>
>> http://www.jsw.gen.nz/mythtv/lirc-ubuntu-18.04-install.sh
>>
>> I spent a fair few hours working out how to fix LIRC, but now that I
>> have, it works properly as normal and you should not need much effort
>> to get it going.  You just need to run the lirc-setup program and
>> adjust a couple of names in your LIRC config files and it should all
>> work, if you have a remote such as an MCE or Hauppauge that uses the
>> devinput driver.
>>
>> I do not think you have said what version of MythTV you are running -
>> is it v30+fixes?
>>
>> >Allen
>> _______________________________________________
>>
>
>MythTV froze again this morning and I will try to clarify the behavior and
>then ask for some specific help.
>
>As suggested I had left a terminal window open and there were no messages
>but the cursor was working. I tried closing myth using the close click
>selection on the dropdown in the GUI. At that point I got the dialog about
>do I really want to close the non responsive program. I moved the terminal
>over as suggested and was able to use the mouse to close Myth.  I restarted
>it without problems.  My wife started the show clicking on resume from
>bookmark and it went to the same point in the program and froze again. This
>time I tried the CTRL-ALT-BS and everything on the GUI closed down but
>nothing restarted as it normally does. Upstairs to open a remote session
>and did a shdo shutdown now -r.  About 5 minutes later the computer finally
>restarted and things worked fine.  We even played through the scene that
>froze without incident. It is possible that the CTRL-ALT-BS would have
>worked if I had waited 5 minutes but I did not.
>
>I am going to assume that the GUI is hanging up and causing the 5 minute
>delay on shutdown.  I am also going to assume that is why CTRL-ALT-BS did
>not work. An acceptable solution for my use of Myth would be to have
>CTRL-ALT-BS close a frozen myth without a 5 minute delay. When I was
>running Mythbuntu 8.04 we occasionally had myth freeze and used CTRL-ALT-BS
>to resume and that was fine. Can anyone tell me how to make Myth close
>without hanging the system for 5 minutes?
>
>PS.  I did fsck as suggested a few days ago and there were no errors.
>
>
>Allen

There is no need to go upstairs to use a remote session.  If you do
Ctrl-Alt-F1 you should get a text mode screen running a terminal
session where you can login and kill things or restart X.

I am surprised that Ctrl-Alt-BS works.  When I last tried it, probably
Ubuntu 12, it was disabled.  I think it is possible to enable it, but
my recollection from back then is that the reason it is disabled is
that it was not likely to work as well as it used to in earlier
versions due to changes in the way all the GUI setup works.  My
experience is that when I have had to restart X using "systemctl
restart lightdm", it restarts rapidly even if there is a frozen
program.  But it is a while since I last had to do it - Ubuntu 16.04
probably.  I am suspecting that your problem with Ctrl-Alt-BS may not
be related to having a frozen mythfrontend.  You should probably test
using it when mythfrontend is running normally to find out.

Are you running LIRC for your remote control?  Does it have a spare
button that you are not using like the Power button at the top of my
MCE remote?  If so, you could program LIRC and irexec to use that
button to execute a command such as "systemctl restart lightdm".  Or
just "pkill mythfrontend.re".  Or a script that does the pkill first
and on a second press of the button does the restart command.


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