Comment by saghm

Because the entire cgroup gets killed rather than individual processes, there's zero trace left. When k first encountered it I was running a multi day compute pipeline in tmux, and I saw my compute pane gone, and thought that I just have accidentally nuked the entire pane, killing the job. A few more attempts and I finally realized it wasn't me, and I checked journactl to find out that it was OOM killed but I couldn't for the life of me figure out why the shell got killed to, what's the point of killing a process with tiny memory? Turns out that is the desired behavior of systemd, and thus of many distributions now.