Dnscrypt-proxy.service crashing with status=31/SYS (solution)

Hi Guys,

I am not sure when the problem started, but one day I was checking the status of dnscrypt-proxy service and noticed that it had crashed and there was little information about it in the System Journal. Just that:

systemd[1]: Created slice Slice /system/systemd-coredump.
systemd[1]: Started Process Core Dump (PID 1866/UID 0).
systemd-coredump[1867]: Process 1033 (dnscrypt-proxy) of user 62582 dumped core.
systemd[1]: systemd-coredump@0-1866-0.service: Deactivated successfully.
systemd[1]: dnscrypt-proxy.service: Main process exited, code=killed, status=31/SYS

I had no idea what was causing it.

I spent several days looking for an explanation until I stumbled upon this post:
https://unix.stackexchange.com/questions/678494/troubleshoot-a-systemd-service-crash-because-of-systemcallfilter

There, somebody had a similar situation, but with a different service and in an OpenSUSE linux. However the author described the culprit (a line within the service file):

SystemCallFilter=~ ... @privileged ...

So, I decided to try it out… and it worked! If I removed that item from dnscrypt-proxy.service everything returned to normal. No more crashes!

At the original post the author says:

When the service is killed no useful information is logged to the System Journal. Only

Main process exited, code=killed, status=31/SYS

The manual says:

@privileged All system calls which need super-user capabilities (capabilities(7))

It seems that there is something wrong with systemd, but I have no clue what it is. Furthermore, I have a version of Manjaro XFCE running in a VirtualBox VM that is very similar to the host machine (that had the dnscrypt-proxy problem) but it is running without problems.

Anyway… I hope that this post can help somebody.

Cheers.