nvidia-persistenced.service conf does not make sense

[Jens Elkner]

The /lib/systemd/system/nvidia-persistenced.service from the nvidia-kernel-common-XXX doesn't make any sense and introducing another uid and gid is not needed at all. The documentation says, that the only purpose is to have a GPU client running, so that the GPUs do not get unloaded/uninitialized. So the user, who is actually running the service does not matter at all, but as usual, it should not be root - what is currently the case =8-( .

So to fix this flaw, one should a) use the DynamicUser directive and b) use the RuntimeDirectory directive to let systemd create and delete the on start/stop with proper permissions (and yes, the --user and --gid options as well as its runtime directory "management" of the nvidia-persistenced binary are IMHO completely useless, just overhead).

E.g. the following script works as expected (unless the bogus /lib/udev/rules.d/71-nvidia.rules wasn't fixed):

[Unit]
Description=NVIDIA Persistence Daemon
After=syslog.target

[Service]
Type=forking
PIDFile=/run/nvidia-persistenced/nvidia-persistenced.pid
DynamicUser=true
RuntimeDirectory=nvidia-persistenced
ExecStart=/usr/bin/nvidia-persistenced --verbose
TimeoutSec=60

[Install]
WantedBy=multi-user.target

BTW: The fix for /lib/udev/rules.d/71-nvidia.rules is:
    sed -i -e '/nvidia-persistenced/ d' /lib/udev/rules.d/71-nvidia.rules
Starting a service via udev trigger is a really, really, really bad idea!!!