How to set PID using ns_last_pid
So there is this cool project called CRIU (Checkpoint/Restore In Userspace). And I was wondering how it gets certain PID when restoring a process. I always thought that it is not possible to set PID without some kind of kernel hacking. I did some investigation and here is what I figured out. There is a file /proc/sys/kernel/ns_last_pid, which contains the last PID that was assigned by the kernel. So, when the kernel needs to assign a new one, it looks into ns_last_pid, gets last_pid, and assigns last_pid + 1....