Ever had a Linux system hang? Fear not! For there is a way to shut it down gracefully!

Most problems related to enabling the Magic SysRq shortcuts are related to bad feedback. You could always try REISUB, without any programs running. It is often not enabled on some Distros.

Sure it is not enabled already?

Take a look at your live journal, while pressing ALT + SysRq + h:

journalctl -f

You should see a new entry pop up, detailing the shortcuts that are possible with SysRq:

Jun 24 11:59:08 prors kernel: sysrq: HELP :
loglevel(0-9) reboot(b) crash(c) terminate-all-tasks(e)
memory-full-oom-kill(f) kill-all-tasks(i) thaw-filesystems(j)
sak(k) show-backtrace-all-active-cpus(l) show-memory-usage(m)
nice-all-RT-tasks(n) poweroff(o) show-registers(p)
show-all-timers(q) unraw(r) sync(s) show-task-states(t)
unmount(u) force-fb(v) show-blocked-tasks(w) dump-ftrace-buffer(z)