zypper up kernel-default
zypper up glibc
zypper up systemd
but none on dracut, udev and any other packages where updates might also be available.
The impeded system can be brought into working condition again by a skilled Linux System Administrator, but this is an unnecessary interrupt to services.
If there is an update for a package, there is a good chance that this will for a seamless integration also require an update to other packages.
It is generelly recommended to do
and update all and every installed package on the system to prevent any incoherence in the system. This is especially true for everything connected to boot and root filesystem and base system like for example