[PATCH -next] selftests/landlock: Fix selftest ptrace_test run fail

[limin]

Tests PTRACE_ATTACH and PTRACE_MODE_READ on the parent,
trace parent return -1 when child== 0
How to reproduce warning:
$ make -C tools/testing/selftests TARGETS=landlock run_tests

Signed-off-by: limin <limin100 at huawei.com>
---
 tools/testing/selftests/landlock/ptrace_test.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/landlock/ptrace_test.c b/tools/testing/selftests/landlock/ptrace_test.c
index c28ef98ff3ac..88c4dc63eea0 100644
--- a/tools/testing/selftests/landlock/ptrace_test.c
+++ b/tools/testing/selftests/landlock/ptrace_test.c
@@ -267,12 +267,11 @@ TEST_F(hierarchy, trace)
 		/* Tests PTRACE_ATTACH and PTRACE_MODE_READ on the parent. */
 		err_proc_read = test_ptrace_read(parent);
 		ret = ptrace(PTRACE_ATTACH, parent, NULL, 0);
+		EXPECT_EQ(-1, ret);
+		EXPECT_EQ(EPERM, errno);
 		if (variant->domain_child) {
-			EXPECT_EQ(-1, ret);
-			EXPECT_EQ(EPERM, errno);
 			EXPECT_EQ(EACCES, err_proc_read);
 		} else {
-			EXPECT_EQ(0, ret);
 			EXPECT_EQ(0, err_proc_read);
 		}
 		if (ret == 0) {
-- 
2.33.0