I was depending on the net_cls subsystem in cgroup v1.
But someone changed the config between kernel 6.12.9 and 6.13.0 to not include it!
pavin@suse-pc:~> cat /usr/lib/modules/6.12.9-1-default/config | grep CONFIG_NET_CLS_CGROUP
CONFIG_NET_CLS_CGROUP=m
pavin@suse-pc:~> cat /usr/lib/modules/6.13.0-1-default/config | grep CONFIG_NET_CLS_CGROUP
# CONFIG_NET_CLS_CGROUP is not set