Security researcher and MateSSL founder, Andrew Ayer has uncovered a bug which will either crash or make systemd unstable (depending on who you talk to) on pretty much every linux distro. David Strauss posted a highly critical response to Ayer. In true pedantic nerd-fight fashion there is a bit of back and forth between them over the "true" severity of the issue and what not.
Nerd fights aside, how you feel about this bug, will probably largely depend on how you feel about systemd in general.
The following command, when run as any user, will crash systemd:
NOTIFY_SOCKET=/run/systemd/notify systemd-notify ""
After running this command, PID 1 is hung in the
pause
system call. You can no longer start and stop daemons. inetd-style services no longer accept connections. You cannot cleanly reboot the system. The system feels generally unstable (e.g. ssh and su hang for 30 seconds since systemd is now integrated with the login system). All of this can be caused by a command that's short enough to fit in a Tweet.Edit (2016-09-28 21:34): Some people can only reproduce if they wrap the command in a
while true
loop. Yay non-determinism!
(Score: 0) by Anonymous Coward on Wednesday October 05 2016, @03:43PM
So you didn't install kernel patches for over a year?
Anyway, such uptime should be easy to achieve (not tested): Start BIOS, set time to past, boot OS, set time to correct value (or let NTP do that).