When booting 4.12-4.12.2, most of the time, my systems locks up hard. No
traces, neither with lockdep enabled. Happens both with -default and -vanilla.

It seems not to happen when booted in single mode and switching to init level 3
manually. It happens when booting directly to level 3 or 5.

nomodeset has no effect.

kdump does not seem to work with 4.12 here.

After the lockup, the system reboots after 90 seconds, it seems (panic?).

It has not happened with my no-modules bzImage. Trying further.

Does not happen with any of 4.11.*.