On Fri, 17 Oct 2014 15:28:18 +0200
Moritz <moritz.tacke@gmail.com> wrote:
* What led up to the situation?
After the last upgrade, the system would not halt any more. Instead,
it runs into a restart cycle. The restart bypasses GRUB, i.e. one a
computer with multiple OS, it restarts linux directly. The machine in
use is a Lenovo Thinkpad X220.
[...]
Do you have kexec-tools installed by chance?
The symptoms you describe (restart bypassing GRUB) look suspiciously
close to what kexec-tools does (it redirects /sbin/reboot and friends
to its own binaries which do "hot" kernel reboot, that is, not going
through the usual "cold" path of going through the BIOS, boot loader
etc).
Try to find out if you have /sbin/coldreboot binary as well.