[PATCH RFC bpf-next 5/5] selftests/bpf: add testcases for tracing session

[Menglong Dong <menglong8.dong@gmail.com>]

Add testcases for BPF_TRACE_SESSION.

Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
---
 .../selftests/bpf/prog_tests/fsession_test.c  | 136 +++++++++++++
 .../selftests/bpf/progs/fsession_test.c       | 178 ++++++++++++++++++
 2 files changed, 314 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/fsession_test.c
 create mode 100644 tools/testing/selftests/bpf/progs/fsession_test.c

diff --git a/tools/testing/selftests/bpf/prog_tests/fsession_test.c b/tools/testing/selftests/bpf/prog_tests/fsession_test.c
new file mode 100644
index 000000000000..e2913da57b38
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/fsession_test.c
@@ -0,0 +1,136 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2025 ChinaTelecom */
+#include <test_progs.h>
+#include "fsession_test.skel.h"
+
+static void test_fsession_basic(void)
+{
+	LIBBPF_OPTS(bpf_test_run_opts, topts);
+	struct fsession_test *skel = NULL;
+	int err, prog_fd;
+
+	skel = fsession_test__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "fsession_test__open_and_load"))
+		goto cleanup;
+
+	err = fsession_test__attach(skel);
+	if (!ASSERT_OK(err, "fsession_attach"))
+		goto cleanup;
+
+	/* Trigger test function calls */
+	prog_fd = bpf_program__fd(skel->progs.test1);
+	err = bpf_prog_test_run_opts(prog_fd, &topts);
+	if (!ASSERT_OK(err, "test_run_opts err"))
+		return;
+	if (!ASSERT_OK(topts.retval, "test_run_opts retval"))
+		return;
+
+	/* Verify test1: both entry and exit are called */
+	ASSERT_EQ(skel->bss->test1_entry_called, 1, "test1_entry_called");
+	ASSERT_EQ(skel->bss->test1_exit_called, 1, "test1_exit_called");
+	ASSERT_EQ(skel->bss->test1_entry_result, 1, "test1_entry_result");
+	ASSERT_EQ(skel->bss->test1_exit_result, 1, "test1_exit_result");
+
+	/* Verify test2: entry is called but exit is blocked */
+	ASSERT_EQ(skel->bss->test2_entry_called, 1, "test2_entry_called");
+	ASSERT_EQ(skel->bss->test2_exit_called, 0, "test2_exit_not_called");
+	ASSERT_EQ(skel->bss->test2_entry_result, 1, "test2_entry_result");
+	ASSERT_EQ(skel->bss->test2_exit_result, 0, "test2_exit_result");
+
+	/* Verify test3: both entry and exit are called */
+	ASSERT_EQ(skel->bss->test3_entry_called, 1, "test3_entry_called");
+	ASSERT_EQ(skel->bss->test3_exit_called, 1, "test3_exit_called");
+	ASSERT_EQ(skel->bss->test3_entry_result, 1, "test3_entry_result");
+	ASSERT_EQ(skel->bss->test3_exit_result, 1, "test3_exit_result");
+
+	/* Verify test4: both entry and exit are called */
+	ASSERT_EQ(skel->bss->test4_entry_called, 1, "test4_entry_called");
+	ASSERT_EQ(skel->bss->test4_exit_called, 1, "test4_exit_called");
+	ASSERT_EQ(skel->bss->test4_entry_result, 1, "test4_entry_result");
+	ASSERT_EQ(skel->bss->test4_exit_result, 1, "test4_exit_result");
+
+	/* Verify test5: both entry and exit are called */
+	ASSERT_EQ(skel->bss->test5_entry_called, 1, "test5_entry_called");
+	ASSERT_EQ(skel->bss->test5_exit_called, 1, "test5_exit_called");
+	ASSERT_EQ(skel->bss->test5_entry_result, 1, "test5_entry_result");
+	ASSERT_EQ(skel->bss->test5_exit_result, 1, "test5_exit_result");
+
+	/* Verify test6: entry is called but exit is blocked */
+	ASSERT_EQ(skel->bss->test6_entry_called, 1, "test6_entry_called");
+	ASSERT_EQ(skel->bss->test6_exit_called, 0, "test6_exit_not_called");
+	ASSERT_EQ(skel->bss->test6_entry_result, 1, "test6_entry_result");
+	ASSERT_EQ(skel->bss->test6_exit_result, 0, "test6_exit_result");
+
+	/* Verify test7: entry is called but exit is blocked */
+	ASSERT_EQ(skel->bss->test7_entry_called, 1, "test7_entry_called");
+	ASSERT_EQ(skel->bss->test7_exit_called, 0, "test7_exit_not_called");
+	ASSERT_EQ(skel->bss->test7_entry_result, 1, "test7_entry_result");
+	ASSERT_EQ(skel->bss->test7_exit_result, 0, "test7_exit_result");
+
+cleanup:
+	fsession_test__destroy(skel);
+}
+
+static void test_fsession_reattach(void)
+{
+	struct fsession_test *skel = NULL;
+	int err, prog_fd;
+	LIBBPF_OPTS(bpf_test_run_opts, topts);
+
+	skel = fsession_test__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "fsession_test__open_and_load"))
+		goto cleanup;
+
+	/* First attach */
+	err = fsession_test__attach(skel);
+	if (!ASSERT_OK(err, "fsession_first_attach"))
+		goto cleanup;
+
+	/* Trigger test function calls */
+	prog_fd = bpf_program__fd(skel->progs.test1);
+	err = bpf_prog_test_run_opts(prog_fd, &topts);
+	if (!ASSERT_OK(err, "test_run_opts err"))
+		return;
+	if (!ASSERT_OK(topts.retval, "test_run_opts retval"))
+		return;
+
+	/* Verify first call */
+	ASSERT_EQ(skel->bss->test1_entry_called, 1, "test1_entry_first");
+	ASSERT_EQ(skel->bss->test1_exit_called, 1, "test1_exit_first");
+
+	/* Detach */
+	fsession_test__detach(skel);
+
+	/* Reset counters */
+	memset(skel->bss, 0, sizeof(*skel->bss));
+
+	/* Second attach */
+	err = fsession_test__attach(skel);
+	if (!ASSERT_OK(err, "fsession_second_attach"))
+		goto cleanup;
+
+	err = bpf_prog_test_run_opts(prog_fd, &topts);
+	if (!ASSERT_OK(err, "test_run_opts err"))
+		return;
+	if (!ASSERT_OK(topts.retval, "test_run_opts retval"))
+		return;
+
+	/* Verify second call */
+	ASSERT_EQ(skel->bss->test1_entry_called, 1, "test1_entry_second");
+	ASSERT_EQ(skel->bss->test1_exit_called, 1, "test1_exit_second");
+
+cleanup:
+	fsession_test__destroy(skel);
+}
+
+void test_fsession_test(void)
+{
+#if !defined(__x86_64__)
+	test__skip();
+	return;
+#endif
+	if (test__start_subtest("fsession_basic"))
+		test_fsession_basic();
+	if (test__start_subtest("fsession_reattach"))
+		test_fsession_reattach();
+}
diff --git a/tools/testing/selftests/bpf/progs/fsession_test.c b/tools/testing/selftests/bpf/progs/fsession_test.c
new file mode 100644
index 000000000000..cce2b32f7c2c
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/fsession_test.c
@@ -0,0 +1,178 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2025 ChinaTelecom */
+#include <vmlinux.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+char _license[] SEC("license") = "GPL";
+
+__u64 test1_entry_result = 0;
+__u64 test1_exit_result = 0;
+__u64 test1_entry_called = 0;
+__u64 test1_exit_called = 0;
+
+SEC("fsession/bpf_fentry_test1")
+int BPF_PROG(test1, int a)
+{
+	bool is_exit = bpf_tracing_is_exit(ctx);
+
+	if (!is_exit) {
+		/* This is entry */
+		test1_entry_called = 1;
+		test1_entry_result = a == 1;
+		return 0; /* Return 0 to allow exit to be called */
+	}
+
+	/* This is exit */
+	test1_exit_called = 1;
+	test1_exit_result = a == 1;
+	return 0;
+}
+
+__u64 test2_entry_result = 0;
+__u64 test2_exit_result = 0;
+__u64 test2_entry_called = 0;
+__u64 test2_exit_called = 0;
+
+SEC("fsession/bpf_fentry_test2")
+int BPF_PROG(test2, int a, __u64 b)
+{
+	bool is_exit = bpf_tracing_is_exit(ctx);
+
+	if (!is_exit) {
+		/* This is entry */
+		test2_entry_called = 1;
+		test2_entry_result = a == 2 && b == 3;
+		return 1; /* Return non-zero value to block exit call */
+	}
+
+	/* This is exit - should not be called due to blocking */
+	test2_exit_called = 1;
+	test2_exit_result = a == 2 && b == 3;
+	return 0;
+}
+
+__u64 test3_entry_result = 0;
+__u64 test3_exit_result = 0;
+__u64 test3_entry_called = 0;
+__u64 test3_exit_called = 0;
+
+SEC("fsession/bpf_fentry_test3")
+int BPF_PROG(test3, char a, int b, __u64 c)
+{
+	bool is_exit = bpf_tracing_is_exit(ctx);
+
+	if (!is_exit) {
+		/* This is entry */
+		test3_entry_called = 1;
+		test3_entry_result = a == 4 && b == 5 && c == 6;
+		return 0; /* Allow exit to be called */
+	}
+
+	/* This is exit */
+	test3_exit_called = 1;
+	test3_exit_result = a == 4 && b == 5 && c == 6;
+	return 0;
+}
+
+__u64 test4_entry_result = 0;
+__u64 test4_exit_result = 0;
+__u64 test4_entry_called = 0;
+__u64 test4_exit_called = 0;
+
+SEC("fsession/bpf_fentry_test4")
+int BPF_PROG(test4, void *a, char b, int c, __u64 d)
+{
+	bool is_exit = bpf_tracing_is_exit(ctx);
+
+	if (!is_exit) {
+		/* This is entry */
+		test4_entry_called = 1;
+		test4_entry_result = a == (void *)7 && b == 8 && c == 9 && d == 10;
+		return 0; /* Allow exit to be called */
+	}
+
+	/* This is exit */
+	test4_exit_called = 1;
+	test4_exit_result = a == (void *)7 && b == 8 && c == 9 && d == 10;
+	return 0;
+}
+
+__u64 test5_entry_result = 0;
+__u64 test5_exit_result = 0;
+__u64 test5_entry_called = 0;
+__u64 test5_exit_called = 0;
+
+SEC("fsession/bpf_fentry_test7")
+int BPF_PROG(test5, struct bpf_fentry_test_t *arg)
+{
+	bool is_exit = bpf_tracing_is_exit(ctx);
+
+	if (!is_exit) {
+		/* This is entry */
+		test5_entry_called = 1;
+		if (!arg)
+			test5_entry_result = 1;
+		return 0; /* Allow exit to be called */
+	}
+
+	/* This is exit */
+	test5_exit_called = 1;
+	if (!arg)
+		test5_exit_result = 1;
+	return 0;
+}
+
+__u64 test6_entry_result = 0;
+__u64 test6_exit_result = 0;
+__u64 test6_entry_called = 0;
+__u64 test6_exit_called = 0;
+
+SEC("fsession/bpf_fentry_test5")
+int BPF_PROG(test6, __u64 a, void *b, short c, int d, __u64 e)
+{
+	bool is_exit = bpf_tracing_is_exit(ctx);
+
+	if (!is_exit) {
+		/* This is entry */
+		test6_entry_called = 1;
+		test6_entry_result = a == 11 && b == (void *)12 && c == 13 && d == 14 &&
+			e == 15;
+		/* Decide whether to block exit call based on condition */
+		if (a == 11)
+			return 1; /* Block exit call */
+		return 0;
+	}
+
+	/* This is exit - should not be called due to blocking */
+	test6_exit_called = 1;
+	test6_exit_result = a == 11 && b == (void *)12 && c == 13 && d == 14 &&
+		e == 15;
+	return 0;
+}
+
+__u64 test7_entry_result = 0;
+__u64 test7_exit_result = 0;
+__u64 test7_entry_called = 0;
+__u64 test7_exit_called = 0;
+
+SEC("fsession/bpf_fentry_test6")
+int BPF_PROG(test7, __u64 a, void *b, short c, int d, void *e, __u64 f)
+{
+	bool is_exit = bpf_tracing_is_exit(ctx);
+
+	if (!is_exit) {
+		/* This is entry */
+		test7_entry_called = 1;
+		test7_entry_result = a == 16 && b == (void *)17 && c == 18 && d == 19 &&
+			e == (void *)20 && f == 21;
+		/* Return non-zero to block exit call */
+		return 1;
+	}
+
+	/* This is exit - should not be called due to blocking */
+	test7_exit_called = 1;
+	test7_exit_result = a == 16 && b == (void *)17 && c == 18 && d == 19 &&
+		e == (void *)20 && f == 21;
+	return 0;
+}
-- 
2.51.0