Revert "selftests/bpf: dummy_st_ops should reject 0 for non-nullable params"

This reverts commit e7d1930 which is
commit 6a2d30d upstream.

The dummy_st_ops/dummy_sleepable_reject_null test requires commit 980ca8c
("bpf: check bpf_dummy_struct_ops program params for test runs"), which in turn
depends on "Support PTR_MAYBE_NULL for struct_ops arguments" series (see link
below), neither are backported to stable 6.6.

Link: https://lore.kernel.org/all/20240209023750.1153905-1-thinker.li@gmail.com/
Signed-off-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: shunghsiyu

tools/testing/selftests/bpf/prog_tests/dummy_st_ops.c

@@ -147,31 +147,6 @@ static void test_dummy_sleepable(void)
 	dummy_st_ops_success__destroy(skel);
 }
 
-/* dummy_st_ops.test_sleepable() parameter is not marked as nullable,
- * thus bpf_prog_test_run_opts() below should be rejected as it tries
- * to pass NULL for this parameter.
- */
-static void test_dummy_sleepable_reject_null(void)
-{
-	__u64 args[1] = {0};
-	LIBBPF_OPTS(bpf_test_run_opts, attr,
-		.ctx_in = args,
-		.ctx_size_in = sizeof(args),
-	);
-	struct dummy_st_ops_success *skel;
-	int fd, err;
-
-	skel = dummy_st_ops_success__open_and_load();
-	if (!ASSERT_OK_PTR(skel, "dummy_st_ops_load"))
-		return;
-
-	fd = bpf_program__fd(skel->progs.test_sleepable);
-	err = bpf_prog_test_run_opts(fd, &attr);
-	ASSERT_EQ(err, -EINVAL, "test_run");
-
-	dummy_st_ops_success__destroy(skel);
-}
-
 void test_dummy_st_ops(void)
 {
 	if (test__start_subtest("dummy_st_ops_attach"))
@@ -184,8 +159,6 @@ void test_dummy_st_ops(void)
 		test_dummy_multiple_args();
 	if (test__start_subtest("dummy_sleepable"))
 		test_dummy_sleepable();
-	if (test__start_subtest("dummy_sleepable_reject_null"))
-		test_dummy_sleepable_reject_null();
 
 	RUN_TESTS(dummy_st_ops_fail);
 }