Merge branch 'bpf, sockmap: Fix infinite recursion in sock_map_close'

Jakub Sitnicki says:

====================

This patch set addresses the syzbot report in [1].

Patch #1 has been suggested by Eric [2]. I extended it to cover the rest of
sock_map proto callbacks. Otherwise we would still overflow the stack.

Patch #2 contains the actual fix and bug analysis.
Patches #3 & #4 add coverage to selftests to trigger the bug.

[1] https://lore.kernel.org/all/00000000000073b14905ef2e7401@google.com/
[2] https://lore.kernel.org/all/CANn89iK2UN1FmdUcH12fv_xiZkv2G+Nskvmq7fG6aA_6VKRf6g@mail.gmail.com/
---
v1 -> v2:
v1: https://lore.kernel.org/r/20230113-sockmap-fix-v1-0-d3cad092ee10@cloudflare.com
[v1 didn't hit bpf@ ML by mistake]

 * pull in Eric's patch to protect against recursion loop bugs (Eric)
 * add a macro helper to check if pointer is inside a memory range (Eric)
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>