Zombie processes in LibreOffice Transformer container

[AFaust]

Running the LibreOffice Transformer container with image version 2.3.6 on Ubuntu 20.04 LTS using a Docker Compose deployment of ACS Community 6.2 GA, we have observed soffice zombie processes accumulating over time.

When logging in to the customer environment, I was greated by the following:

Welcome to Ubuntu 20.04.1 LTS (GNU/Linux 5.4.0-62-generic x86_64)

 * Documentation:  https://help.ubuntu.com
 * Management:     https://landscape.canonical.com
 * Support:        https://ubuntu.com/advantage

  System information as of Thu 11 Feb 2021 03:04:17 PM UTC

  System load:                      0.12
  Usage of /:                       28.6% of 97.44GB
  Memory usage:                     74%
  Swap usage:                       17%
  Processes:                        271
  Users logged in:                  0
  IPv4 address for br-2fb05fc25e4c: 172.30.0.1
  IPv4 address for docker0:         172.17.0.1
  IPv4 address for ens160:          172.23.224.105

  => There are 11 zombie processes.

Checking for defunct processes yielded:

alfadmin@sthjnalf001:~$ ps axo stat,ppid,pid,comm | grep -w defunct
Z       1685    3073 soffice.bin <defunct>
Z       1685 1013780 soffice.bin <defunct>
Z       1685 1060187 soffice.bin <defunct>
Z       1685 1604515 soffice.bin <defunct>
Z       1685 1839369 soffice.bin <defunct>
Z       1685 1982672 soffice.bin <defunct>
Z       1685 2342380 soffice.bin <defunct>
Z       1685 2459218 soffice.bin <defunct>
Z       1685 2461051 soffice.bin <defunct>
Z       1685 2463188 soffice.bin <defunct>
Z       1685 2566739 soffice.bin <defunct>

A simple docker-compose restart <libreoffice-service-name> clears all these processes.

[loftux]

This is still happening, only this time observed in alfresco-transform-core-aio version 2.5.3 and 3.0.0

[loftux]

This seems to be a libreoffice issue, found two tickets
https://bugs.documentfoundation.org/show_bug.cgi?id=95843
https://bugs.documentfoundation.org/show_bug.cgi?id=117523