[mythtv-users] Inhibit crash dumps (fixed)

[John]

On 10/05/2020 10:37, Stephen Worthington wrote:
> On Sun, 10 May 2020 09:58:45 +0100, you wrote:
>
>> MythTV Version : v31.0-38-ga2b8c262dc on Ubuntu 20.04
>>
>> The frontend is working fine but crashing on exit. This occurs on one of
>> my frontends but not others.
>>
>> mythshutdown also core dumps on exit when running on my Ubuntu 19.10 server.
>>
>> Both work fine but on one of my frontends it keeps creating a large core
>> dump file in /var/crash
>>
>> ie /var/crash/usr_bin_mythfrontend.real.1000.crash
>>
>> Does any body know how to stop the core dump files being created
> I think that involves the ulimit command to set the crash dump file
> size to 0.  And if you look at /etc/security/limits.d/ (in Ubuntu), I
> think you can add a config file there to match a program and provide
> individual settings for it.  But I have not actually ever done that,
> so google to see the right way of doing it.
>
> When you get a core dump, did the program exit normally, or did you
> need to kill it?  If the latter, instead of using kill -9, try using
> the ordinary kill command (aka kill -15) twice.  For a long time
> MythTV programs have had a problem where they try to shut down on the
> first kill command, but one thread fails to shut down.  If you do a
> second ordinary kill command, that last thread shuts down normally, so
> there is no crash.
>
> If you are using systemd to shut the MythTV program down, then systemd
> on its default settings will do an ordinary kill command once to tell
> a program to shut down, and then if the program fails to shut down, it
> will do a kill -9 after a timeout.  You can change that to making
> systemd do two ordinary kill commands with a short delay between them
> by adding an override for the systemd settings.  I have this set up
> for mythbackend, where I add an override line (using sudo systemctl
> edit mythtv-backend):
>
> [Service]
> ExecStop=/usr/local/bin/mythbackendstop.sh
>
> And then /usr/local/bin/mythbackendstop.sh does this:
>
> #!/bin/bash
> PID=$(systemctl show -p MainPID mythtv-backend.service 2>/dev/null |
> cut -d= -f2)
> if [ "$PID" != "0" ]; then
>      kill -15 $PID
>      sleep 1
>      kill -15 $PID
> fi
>
> The PID= line is all one long line - my email client wraps long lines.
>
> Doing this makes my system shut down much faster as it does not have
> to wait for a timeout before systemd finally does a kill -9 for
> mythbackend.
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Thanks

Setting limits.conf in /etc/security/limits.d to
* soft core 0
* hard core 0
worked