RE: [PATCH bpf] bpf, sockmap, udp: sk_prot needs inuse_idx set for proc stats

Jakub Sitnicki wrote:

Proc socket stats use sk_prot->inuse_idx value to record inuse sock stats.
We currently do not set this correctly from sockmap side. The result is
reading sock stats '/proc/net/sockstat' gives incorrect values. The
socket counter is incremented correctly, but because we don't set the
counter correctly when we replace sk_prot we may omit the decrement.

To get the correct inuse_idx value move the core_initcall that initializes
the udp proto handlers to late_initcall. This way it is initialized after
UDP has the chance to assign the inuse_idx value from the register protocol
handler.

Fixes: 5e21bb4e8125 ("bpf, test: fix NULL pointer dereference on invalid expected_attach_type")
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
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Missing bit from John's fix [1].

[1] https://lore.kernel.org/bpf/20210712195546.423990-1-john.fastabend@gmail.com/T/#mba9e0b6aa8dd0c01d7421a084c62ec93c9eea764 (local)

Yep. Thanks.

Acked-by: John Fastabend <john.fastabend@gmail.com>