Description of problem:

We see a couple of customers getting their /boot filled with initramfs files for non-existing kernels (as shown by "rpm -q kernel-core").
It appears that "dracut --regenerate-all" bases itself on the existence of /lib/modules/<KVERS> directory, which leads to creating non-usable initramfs files for removed kernels that still have the directory existing, for example because of presence of 3rd party kernel modules.

Filing as Medium/Medium because this leads to space issues in /boot and there is no simple recovery but deleting.

Version-Release number of selected component (if applicable):

dracut-049

How reproducible:

Always

Steps to Reproduce:
1. Create directory for some non-installed kernel

1. mkdir /lib/modules/4.18.0-372.9.1.el8.x86_64

2. Execute dracut

1. dracut /tmp/foo.img 4.18.0-372.9.1.el8.x86_64

Actual results:

/tmp/foo.img created

Expected results:

Some error

Additional info:

I think dracut should check that there is really some kernel available, e.g. through checking presence of /boot/vmlinuz-<KVERS>, or failing if some critical kernel files are missing.