[PATCH bpf-next 8/8] selftests/bpf: Add a test to verify session-kfunc compatibility enforcement
From: Leon Hwang <hidden>
Date: 2026-02-24 15:43:00
Also in:
bpf, linux-kselftest, lkml
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [selftests] (test runners & infrastructure), kernel selftest framework, the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Shuah Khan, Linus Torvalds
Add prog_array coverage for tracing programs that differ in bpf_session_cookie() / bpf_session_is_return() usage. The test verifies one-way enforcement: !call_session_* programs cannot tail-call call_session_* programs. Assisted-by: Codex:gpt-5.3-codex Signed-off-by: Leon Hwang <redacted> --- .../selftests/bpf/prog_tests/fsession_test.c | 47 +++++++++++++++++++ .../selftests/bpf/progs/fsession_test.c | 6 +++ 2 files changed, 53 insertions(+)
diff --git a/tools/testing/selftests/bpf/prog_tests/fsession_test.c b/tools/testing/selftests/bpf/prog_tests/fsession_test.c
index a299aeb8cc2e..304986544a8d 100644
--- a/tools/testing/selftests/bpf/prog_tests/fsession_test.c
+++ b/tools/testing/selftests/bpf/prog_tests/fsession_test.c@@ -129,6 +129,51 @@ static void test_fsession_cookie(void) fsession_test__destroy(skel); } +static void test_fsession_prog_array_session_kfunc_compat(void) +{ + struct fsession_test *skel = NULL; + __u32 key = 0, session_kfunc_prog_fd, no_session_kfunc_prog_fd; + int map_fd = -1, err; + + skel = fsession_test__open(); + if (!ASSERT_OK_PTR(skel, "fsession_test__open")) + goto cleanup; + + err = fsession_test__load(skel); + if (err == -EOPNOTSUPP) { + test__skip(); + goto cleanup; + } + if (!ASSERT_OK(err, "fsession_test__load")) + goto cleanup; + + session_kfunc_prog_fd = bpf_program__fd(skel->progs.test9); + no_session_kfunc_prog_fd = bpf_program__fd(skel->progs.test12); + if (!ASSERT_GE(session_kfunc_prog_fd, 0, "session_kfunc_prog_fd")) + goto cleanup; + if (!ASSERT_GE(no_session_kfunc_prog_fd, 0, "no_session_kfunc_prog_fd")) + goto cleanup; + + map_fd = bpf_map_create(BPF_MAP_TYPE_PROG_ARRAY, NULL, sizeof(key), + sizeof(__u32), 1, NULL); + if (!ASSERT_GE(map_fd, 0, "bpf_map_create")) + goto cleanup; + + err = bpf_map_update_elem(map_fd, &key, &no_session_kfunc_prog_fd, BPF_ANY); + if (!ASSERT_OK(err, "bpf_map_update_elem success")) + goto cleanup; + + err = bpf_map_update_elem(map_fd, &key, &session_kfunc_prog_fd, BPF_ANY); + if (!ASSERT_ERR(err, "bpf_map_update_elem failure")) + goto cleanup; + ASSERT_EQ(errno, EINVAL, "bpf_map_update_elem errno"); + +cleanup: + if (map_fd >= 0) + close(map_fd); + fsession_test__destroy(skel); +} + void test_fsession_test(void) { if (test__start_subtest("fsession_test"))
@@ -137,4 +182,6 @@ void test_fsession_test(void) test_fsession_reattach(); if (test__start_subtest("fsession_cookie")) test_fsession_cookie(); + if (test__start_subtest("fsession_prog_array_session_kfunc_compat")) + test_fsession_prog_array_session_kfunc_compat(); }
diff --git a/tools/testing/selftests/bpf/progs/fsession_test.c b/tools/testing/selftests/bpf/progs/fsession_test.c
index 86e8a2fe467e..1e6be28bcc3d 100644
--- a/tools/testing/selftests/bpf/progs/fsession_test.c
+++ b/tools/testing/selftests/bpf/progs/fsession_test.c@@ -177,3 +177,9 @@ int BPF_PROG(test11, int a) test11_result = a == 1; return 0; } + +SEC("fsession/bpf_fentry_test1") +int BPF_PROG(test12, int a, int ret) +{ + return 0; +}
--
2.52.0