CVE-2024-40993

In the Linux kernel, the following vulnerability has been resolved:

netfilter: ipset: Fix suspicious rcu_dereference_protected()

When destroying all sets, we are either in pernet exit phase or

are executing a "destroy all sets command" from userspace. The latter

was taken into account in ip_set_dereference() (nfnetlink mutex is held),

but the former was not. The patch adds the required check to

rcu_dereference_protected() in ip_set_dereference().