selftests/bpf: Fix fd cleanup in sk_lookup test

[ Upstream commit c3fc706e94f5653def2783ffcd809a38676b7551 ]

Similar to the fix in commit:
e31eec77e4ab ("bpf: selftests: Fix fd cleanup in get_branch_snapshot")

We use designated initializer to set fds to -1 without breaking on
future changes to MAX_SERVER constant denoting the array size.

The particular close(0) occurs on non-reuseport tests, so it can be seen
with -n 115/{2,3} but not 115/4. This can cause problems with future
tests if they depend on BTF fd never being acquired as fd 0, breaking
internal libbpf assumptions.

Fixes: 0ab5539f8584 ("selftests/bpf: Tests for BPF_SK_LOOKUP attach point")
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20211028063501.2239335-8-memxor@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/tools/testing/selftests/bpf/prog_tests/sk_lookup.c b/tools/testing/selftests/bpf/prog_tests/sk_lookup.c
index aee4154..6db0740 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/sk_lookup.c
+++ b/tools/testing/selftests/bpf/prog_tests/sk_lookup.c
@@ -598,7 +598,7 @@ close:
 
 static void run_lookup_prog(const struct test *t)
 {
-       int server_fds[MAX_SERVERS] = { -1 };
+       int server_fds[] = { [0 ... MAX_SERVERS - 1] = -1 };
        int client_fd, reuse_conn_fd = -1;
        struct bpf_link *lookup_link;
        int i, err;
@@ -1053,7 +1053,7 @@ static void run_sk_assign(struct test_sk_lookup *skel,
                          struct bpf_program *lookup_prog,
                          const char *remote_ip, const char *local_ip)
 {
-       int server_fds[MAX_SERVERS] = { -1 };
+       int server_fds[] = { [0 ... MAX_SERVERS - 1] = -1 };
        struct bpf_sk_lookup ctx;
        __u64 server_cookie;
        int i, err;