bpf, sockmap: Don't let sock_map_{close,destroy,unhash} call itself

mainline inclusion
from mainline-v6.2-rc7
commit 5b4a79ba
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I65HYE
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=5b4a79ba65a1ab479903fff2e604865d229b70a9

---------------------------

sock_map proto callbacks should never call themselves by design. Protect
against bugs like [1] and break out of the recursive loop to avoid a stack
overflow in favor of a resource leak.

[1] https://lore.kernel.org/all/00000000000073b14905ef2e7401@google.com/



Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/r/20230113-sockmap-fix-v2-1-1e0ee7ac2f90@cloudflare.com


Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Liu Jian <liujian56@huawei.com>