Any trick to remove a D-state dead process without rebooting?

[Yun-Chih Chen]

Hi, fellows:

Does anyone know of any hacks that remove a D-state dead process whose
parent is pid=1 (actually systemd), without rebooting?

Someone posed a trick on the net, but not sure how he did it:
https://serverfault.com/questions/76263/how-to-kill-a-defunct-process-with-parent-1

Because the dead process is wrapped as a Systemd unit, I've also asked
at Systemd's mailing list without avail:
https://lists.freedesktop.org/archives/systemd-devel/2017-December/039941.html

Appreciate any hint or even dirty hacks!
Thanks in advance!

Yunchih