AZL-95042

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

wifi: mac80211: defer link RX stats percpu free to RCU

staremovelink() frees a removed MLO link's RX stats percpu buffer right away, but defers only the link container to RCU:

sta_info_free_link(&alloc->info);
kfree_rcu(alloc, rcu_head);

The RX fast path reads linksta under rcureadlock and writes the percpu stats. A reader that resolved linksta before the removal keeps the pointer. The container stays alive from the kfreercu, so the read still works. But the percpu block it points to is already freed. This needs usesrss. That is when pcpurxstats exists.

The full STA teardown frees the deflink stats only after synchronize_net(). The link removal path had no such barrier. The race is hard to win in practice, but the free should still wait for RCU.

Free the link together with its data from a single RCU callback, so the percpu block is reclaimed only after readers drain.