xen-kernel -- Certain domctl operations may be abused to lock up the host

The Xen Project reports:

XSA-77 put the majority of the domctl operations on a list
excepting them from having security advisories issued for them if
any effects their use might have could hamper security. Subsequently
some of them got declared disaggregation safe, but for a small
subset this was not really correct: Their (mis-)use may result in
host lockups.
As a result, the potential security benefits of toolstack
disaggregation are not always fully realised.
Domains deliberately given partial management control may be able
to deny service to the entire host.
As a result, in a system designed to enhance security by radically
disaggregating the management, the security may be reduced. But,
the security will be no worse than a non-disaggregated design.