> Likely you've previously loaded a non-MLS policy into your
> kernel, and the kernel will not allow a non-MLS -> MLS (or
> vice versa) switch at runtime. You'll have to reboot to
> bring it up with the MLS-enabled policy.
Yes, that was the case. After rebooting, everything went fine and the new MCS policy has been loaded. Then I reinstalled the custom modules.
I suspected something like that, but was afraid of rebooting into a broken system and then having to rescue it...
Thanks very much for your advice !
Best regards,
Guido