Comment 4 for bug 1886668

This is caused by net_cls and net_prio cgroups disabling cgroup BPF and
causing it to stop refcounting when allocating new sockets. Releasing those
sockets will cause the refcount to go negative, leading to the potential
use-after-free.

Though this revert won't prevent the issue from happening as it could still
theoretically be caused by setting net_cls.classid or net_prio.ifpriomap,
this will prevent it from happening on default system configurations. A
combination of systemd use of cgroup BPF and extensive cgroup use including
net_prio will cause this. Reports usually involve using lxd, libvirt,
docker or kubernetes and some systemd service with IPAddressDeny or
IPAddressAllow.

And though this patch has been introduced to avoid some potential memory
leaks, the cure is worse than the disease. We will need to revisit both
issues later on and reapply this patch when we have a real fix for the
crash.

Cascardo.