Is it dangerous to start programs before udev is running, so long as all of the other dependencies of these programs (such as /var and /home being read-write) have been satisfied? Or do programs assume that udev has actually started, not merely bound to its sockets connections? The reason I ask is that I'm using systemd-udevd with a non-systemd service manager (s6 + s6-rc) and it has an incompatible method for readiness notification (writing a newline to a file descriptor). s6-rc has full support for dependencies, so I can easily have udev write to a FIFO when it picks up /dev/zero and have other things depend on that, but I'm curious if there are any other problems with this approach. In case it matters, the only programs running on the machine will be some VMs, a few programs to support them, a Wayland compositor (now Weston, eventually COSMIC), some XDG portals, and possibly a couple of others. No code not included in the (signed and dm-verity protected) root filesystem will be allowed to execute. -- Sincerely, Demi Marie Obenour (she/her/hers)