My system has been continuously upgraded (dnf system-upgrade) since Fedora 30.

It appears that the combination of systemd and the kernel in Fedora 41 no longer support cgroups v1.

After a successful system upgrade, my system will not boot: systemd fails with an error message.

    systemd[1]: Freezing execution.

It then prompts me to set SYSTEMD_CGROUP_ENABLE_LEGACY_FORCE=1 on the kernel command line. This works round the problem temporarily.

Reproducible: Always

Steps to Reproduce:
1. Use dnf system-upgrade to upgrade from Fedora 30, to 31, to 32... to 40.
2. Upgrade to Fedora 41
3. Reboot
Actual Results:  
System refuses to boot.
Console displays:

  systemd[1]: Freezing execution.


Expected Results:  
A normal boot into my system, upgraded to Fedora 41.
This implies a migration to cgroups v2.

dnf system-upgrade works well - but there is no clear limit on how many time I should upgrade before anything breaks. Also, when there is a major change, it seems that there is no warning that a major feature such as systemd will fail (say) within two years.

I would have expected that between Fedora 30 and 40, that systemd (and my configuration) would have been migrated to cgroup v2.

The console error message tells me to use SYSTEMD_CGROUP_ENABLE_LEGACY_FORCE=1 on the kernel command line. I have done this as a workround (with the annoying 30 second delay). I do not wish to do this and would vastly prefer my system to use cgroups v2.