So there's a decades-old mechanism (and actual standard) how programs lock serial ports on unix-like systems in /var/lock. it's used in practice even in 2025 and #systemd >= 258 simply breaks it with "we don't care". I am not a systemd opponent, but that kind of behaviour [without a prior community-wide discussion or providing patches for known-affected projects and a grace period] is just alienating users and developers https://github.com/systemd/systemd/issues/38563https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1110980 #systemd #debian