In certain cases building the rootfs fails due to failing loop device mount

[0xricksanchez]

Describe the bug

Creating the rootfs can fail in unknown cases when mounting the loop device runs into an unknown problem:

mount: /mnt/rootfs: failed to setup loop device for /io/filesystem-x86_64.

This has been observed on a Manjaro and Fedora36 system.

To Reproduce

1. It happened to me once in a freshly set up Fedora36 system after following the usage-section in the README
2. After deleting the broken filesystem and re-running start_kgdb.py with no changes to the config.ini root file system creation worked for me again.

Expected behavior

• A more sane error message in case of a failure, but really we want a successful rootfs build...

[0xricksanchez]

Closing this for now as it never happened again since it was first observed.