Zombie processes

[kuzminets]

After login on Ubuntu 20.04 I get a notification => There are 2 zombie processes. BTCPay-server runs in docker.

It seems to be lightningd child processes [fetchinvoice] <defunct> and [offers] <defunct>.

The ps auxf output:

root        2435  0.0  0.0 113444   460 ?        Sl   03:40   0:01 /usr/bin/containerd-shim-runc-v2 -namespace moby -id ebcc7fc5a2
root        2464  0.0  0.0   2276   672 ?        Ss   03:40   0:01  \_ /usr/bin/tini -g -- ./entrypoint.sh
root        2578  0.0  1.5  66452 63272 ?        S    03:40   0:11      \_ lightningd
root        4087  0.0  0.0   5956  2596 ?        S    03:40   0:00          \_ /usr/local/bin/../libexec/c-lightning/plugins/autoc
root        4088  0.0  0.0   6448  3812 ?        S    03:40   0:03          \_ /usr/local/bin/../libexec/c-lightning/plugins/bcli
root        4089  0.0  0.0      0     0 ?        Z    03:40   0:00          \_ [fetchinvoice] <defunct>
root        4090  0.0  0.0   6012  2632 ?        S    03:40   0:00          \_ /usr/local/bin/../libexec/c-lightning/plugins/keyse
root        4091  0.0  0.0      0     0 ?        Z    03:40   0:00          \_ [offers] <defunct>
root        4092  0.0  0.0   6072  2596 ?        S    03:40   0:00          \_ /usr/local/bin/../libexec/c-lightning/plugins/pay
root        4093  0.0  0.0   5960  2580 ?        S    03:40   0:00          \_ /usr/local/bin/../libexec/c-lightning/plugins/txpre
root        4094  0.0  0.0   6008  2632 ?        S    03:40   0:00          \_ /usr/local/bin/../libexec/c-lightning/plugins/spend
root        4102  0.0  0.0   6032  2424 ?        SL   03:40   0:00          \_ /usr/local/libexec/c-lightning/lightning_hsmd
root        4103  0.0  0.0   6296  3364 ?        S    03:40   0:00          \_ /usr/local/libexec/c-lightning/lightning_connectd
root        4104  0.0  0.0   6212  3112 ?        S    03:40   0:00          \_ /usr/local/libexec/c-lightning/lightning_gossipd

Why does it happen? Is it something I need to fix? Thanks

[uhlhosting]

Have you tried rebootinng your server? Or clearing the config, backing up, and run setup again.

[kuzminets]

It's a fresh installation. The zombie processes appear after a few minutes the BTCPay server is up. It happens both after server reboot and manual service restart with btcpay-restart.sh

# ps -elf | grep Z
F S UID          PID    PPID  C PRI  NI ADDR SZ WCHAN  STIME TTY          TIME CMD
0 Z root        6928    5483  0  80   0 -     0 -      14:10 ?        00:00:00 [fetchinvoice] <defunct>
0 Z root        6935    5483  0  80   0 -     0 -      14:10 ?        00:00:00 [offers] <defunct>

[jsbryans22]

I have the same thing in my server:

4 Z root      339456  337792  0  80   0 -     0 -      06:34 ?        00:00:00 [fetchinvoice] <defunct>
4 Z root      339464  337792  0  80   0 -     0 -      06:34 ?        00:00:00 [offers] <defunct>
0 S root      357398  356869  0  80   0 -  2040 ?      06:58 pts/0    00:00:00 grep --color=auto Z