selftests/bpf: Test bpf_core_types_are_compat() functionality.

Add several tests to check bpf_core_types_are_compat() functionality:
- candidate type name exists and types match
- candidate type name exists but types don't match
- nested func protos at kernel recursion limit
- nested func protos above kernel recursion limit. Such bpf prog
  is rejected during the load.

Signed-off-by: Matteo Croce <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]

2 files changed, 28 insertions, 1 deletions

diff --git a/tools/testing/selftests/bpf/prog_tests/core_kern.c b/tools/testing/selftests/bpf/prog_tests/core_kern.c
index 561c5185d886..6a5a1c019a5d 100644
--- a/tools/testing/selftests/bpf/prog_tests/core_kern.c
+++ b/tools/testing/selftests/bpf/prog_tests/core_kern.c
@@ -7,8 +7,22 @@
 void test_core_kern_lskel(void)
 {
 	struct core_kern_lskel *skel;
+	int link_fd;
 
 	skel = core_kern_lskel__open_and_load();
-	ASSERT_OK_PTR(skel, "open_and_load");
+	if (!ASSERT_OK_PTR(skel, "open_and_load"))
+		return;
+
+	link_fd = core_kern_lskel__core_relo_proto__attach(skel);
+	if (!ASSERT_GT(link_fd, 0, "attach(core_relo_proto)"))
+		goto cleanup;
+
+	/* trigger tracepoints */
+	usleep(1);
+	ASSERT_TRUE(skel->bss->proto_out[0], "bpf_core_type_exists");
+	ASSERT_FALSE(skel->bss->proto_out[1], "!bpf_core_type_exists");
+	ASSERT_TRUE(skel->bss->proto_out[2], "bpf_core_type_exists. nested");
+
+cleanup:
 	core_kern_lskel__destroy(skel);
 }
diff --git a/tools/testing/selftests/bpf/prog_tests/core_kern_overflow.c b/tools/testing/selftests/bpf/prog_tests/core_kern_overflow.c
new file mode 100644
index 000000000000..04cc145bc26a
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/core_kern_overflow.c
@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "test_progs.h"
+#include "core_kern_overflow.lskel.h"
+
+void test_core_kern_overflow_lskel(void)
+{
+	struct core_kern_overflow_lskel *skel;
+
+	skel = core_kern_overflow_lskel__open_and_load();
+	if (!ASSERT_NULL(skel, "open_and_load"))
+		core_kern_overflow_lskel__destroy(skel);
+}