[PATCH bpf-next v2 3/3] selftests/bpf: Add subtest usdt_multispec_fail with adjustable BPF_USDT_MAX_SPEC_CNT

[Yonghong Song <yonghong.song@linux.dev>]

Add udst_multispec_fail subtest. For arm64/clang20 build, the
BPF_USDT_MAX_SPEC_CNT is set to 2. Otherwise, the BPF_USDT_MAX_SPEC_CNT
remains the default value 256. This resolved the previous test failure.

Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
---
 tools/testing/selftests/bpf/prog_tests/usdt.c          |  7 ++++---
 .../selftests/bpf/progs/test_usdt_multispec_fail.c     | 10 ++++++++++
 2 files changed, 14 insertions(+), 3 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/progs/test_usdt_multispec_fail.c

diff --git a/tools/testing/selftests/bpf/prog_tests/usdt.c b/tools/testing/selftests/bpf/prog_tests/usdt.c
index dc29ef94312a..cc7f38b03a96 100644
--- a/tools/testing/selftests/bpf/prog_tests/usdt.c
+++ b/tools/testing/selftests/bpf/prog_tests/usdt.c
@@ -7,6 +7,7 @@
 
 #include "test_usdt.skel.h"
 #include "test_urandom_usdt.skel.h"
+#include "test_usdt_multispec_fail.skel.h"
 
 int lets_test_this(int);
 
@@ -305,10 +306,10 @@ static void subtest_multispec_usdt(void)
 static void subtest_multispec_fail_usdt(void)
 {
 	LIBBPF_OPTS(bpf_usdt_opts, opts);
-	struct test_usdt *skel;
+	struct test_usdt_multispec_fail *skel;
 	int err;
 
-	skel = test_usdt__open_and_load();
+	skel = test_usdt_multispec_fail__open_and_load();
 	if (!ASSERT_OK_PTR(skel, "skel_open"))
 		return;
 
@@ -322,7 +323,7 @@ static void subtest_multispec_fail_usdt(void)
 	ASSERT_EQ(err, -E2BIG, "usdt_300_attach_err");
 
 cleanup:
-	test_usdt__destroy(skel);
+	test_usdt_multispec_fail__destroy(skel);
 }
 
 static FILE *urand_spawn(int *pid)
diff --git a/tools/testing/selftests/bpf/progs/test_usdt_multispec_fail.c b/tools/testing/selftests/bpf/progs/test_usdt_multispec_fail.c
new file mode 100644
index 000000000000..4cca3d8d45fb
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_usdt_multispec_fail.c
@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */
+
+#if defined(__clang__) && defined(__TARGET_ARCH_arm64)
+#define BPF_USDT_MAX_SPEC_CNT 2
+#endif
+
+int my_pid;
+
+#include "test_usdt_multispec.inc.h"
-- 
2.47.1