On Wed, Apr 08, 2026 at 02:21:07PM +0800, Menglong Dong wrote:
> The fsession attach type is missed in the verifier log in
> check_get_func_ip(), bpf_check_attach_target() and check_attach_btf_id().
> Update them to make the verifier log proper. Meanwhile, update the
> corresponding selftests.
>
> Signed-off-by: Menglong Dong <[email protected]>
> Acked-by: Leon Hwang <[email protected]>
> ---
> v2:
> - add a missing FSESSION in bpf_check_attach_target()
> ---
> kernel/bpf/verifier.c | 10 +++++-----
> tools/testing/selftests/bpf/prog_tests/exceptions.c | 8 ++++----
> tools/testing/selftests/bpf/verifier/sleepable.c | 2 +-
> 3 files changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> index 594260c1f382..beb660b4c3ec 100644
> --- a/kernel/bpf/verifier.c
> +++ b/kernel/bpf/verifier.c
> @@ -11757,7 +11757,7 @@ static int check_get_func_ip(struct bpf_verifier_env
> *env)
>
> if (type == BPF_PROG_TYPE_TRACING) {
> if (!bpf_prog_has_trampoline(env->prog)) {
> - verbose(env, "func %s#%d supported only for
> fentry/fexit/fmod_ret programs\n",
> + verbose(env, "func %s#%d supported only for
> fentry/fexit/fsession/fmod_ret programs\n",
> func_id_name(func_id), func_id);
> return -ENOTSUPP;
> }
> @@ -25561,7 +25561,7 @@ int bpf_check_attach_target(struct bpf_verifier_log
> *log,
> btf = tgt_prog ? tgt_prog->aux->btf : prog->aux->attach_btf;
> if (!btf) {
> bpf_log(log,
> - "FENTRY/FEXIT program can only be attached to another
> program annotated with BTF\n");
> + "FENTRY/FEXIT/FSESSION program can only be attached to
> another program annotated with BTF\n");
I wonder this should say 'Tracing program...' instead,
we have other tracing types not covered in this error
jirka
> return -EINVAL;
> }
> t = btf_type_by_id(btf, btf_id);
> @@ -25597,7 +25597,7 @@ int bpf_check_attach_target(struct bpf_verifier_log
> *log,
> if (aux->func && aux->func[subprog]->aux->exception_cb) {
> bpf_log(log,
> "%s programs cannot attach to exception
> callback\n",
> - prog_extension ? "Extension" : "FENTRY/FEXIT");
> + prog_extension ? "Extension" :
> "FENTRY/FEXIT/FSESSION");
> return -EINVAL;
> }
> conservative = aux->func_info_aux[subprog].unreliable;
> @@ -25686,7 +25686,7 @@ int bpf_check_attach_target(struct bpf_verifier_log
> *log,
> case BPF_TRACE_RAW_TP:
> if (tgt_prog) {
> bpf_log(log,
> - "Only FENTRY/FEXIT progs are attachable to
> another BPF prog\n");
> + "Only FENTRY/FEXIT/FSESSION progs are
> attachable to another BPF prog\n");
> return -EINVAL;
> }
> if (!btf_type_is_typedef(t)) {
> @@ -25952,7 +25952,7 @@ static int check_attach_btf_id(struct
> bpf_verifier_env *env)
> }
>
> if (prog->sleepable && !can_be_sleepable(prog)) {
> - verbose(env, "Only fentry/fexit/fmod_ret, lsm, iter, uprobe,
> and struct_ops programs can be sleepable\n");
> + verbose(env, "Only fentry/fexit/fsession/fmod_ret, lsm, iter,
> uprobe, and struct_ops programs can be sleepable\n");
> return -EINVAL;
> }
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/exceptions.c
> b/tools/testing/selftests/bpf/prog_tests/exceptions.c
> index 84ab73e08b0e..94a62fcd4543 100644
> --- a/tools/testing/selftests/bpf/prog_tests/exceptions.c
> +++ b/tools/testing/selftests/bpf/prog_tests/exceptions.c
> @@ -128,7 +128,7 @@ static void test_exceptions_success(void)
>
> bpf_program__fd(skel->progs.exception_ext_mod_cb_runtime),
> "exception_cb_mod"),
> "set_attach_target"))
> goto done;
> - }), "FENTRY/FEXIT programs cannot attach to exception
> callback", 0);
> + }), "FENTRY/FEXIT/FSESSION programs cannot attach to exception
> callback", 0);
>
> if (test__start_subtest("throwing fentry -> exception_cb"))
> RUN_EXT(-EINVAL, true, ({
> @@ -138,7 +138,7 @@ static void test_exceptions_success(void)
>
> bpf_program__fd(skel->progs.exception_ext_mod_cb_runtime),
> "exception_cb_mod"),
> "set_attach_target"))
> goto done;
> - }), "FENTRY/FEXIT programs cannot attach to exception
> callback", 0);
> + }), "FENTRY/FEXIT/FSESSION programs cannot attach to exception
> callback", 0);
>
> if (test__start_subtest("non-throwing fexit -> exception_cb"))
> RUN_EXT(-EINVAL, true, ({
> @@ -148,7 +148,7 @@ static void test_exceptions_success(void)
>
> bpf_program__fd(skel->progs.exception_ext_mod_cb_runtime),
> "exception_cb_mod"),
> "set_attach_target"))
> goto done;
> - }), "FENTRY/FEXIT programs cannot attach to exception
> callback", 0);
> + }), "FENTRY/FEXIT/FSESSION programs cannot attach to exception
> callback", 0);
>
> if (test__start_subtest("throwing fexit -> exception_cb"))
> RUN_EXT(-EINVAL, true, ({
> @@ -158,7 +158,7 @@ static void test_exceptions_success(void)
>
> bpf_program__fd(skel->progs.exception_ext_mod_cb_runtime),
> "exception_cb_mod"),
> "set_attach_target"))
> goto done;
> - }), "FENTRY/FEXIT programs cannot attach to exception
> callback", 0);
> + }), "FENTRY/FEXIT/FSESSION programs cannot attach to exception
> callback", 0);
>
> if (test__start_subtest("throwing extension (with custom cb) ->
> exception_cb"))
> RUN_EXT(-EINVAL, true, ({
> diff --git a/tools/testing/selftests/bpf/verifier/sleepable.c
> b/tools/testing/selftests/bpf/verifier/sleepable.c
> index 1f0d2bdc673f..c2b7f5ebf168 100644
> --- a/tools/testing/selftests/bpf/verifier/sleepable.c
> +++ b/tools/testing/selftests/bpf/verifier/sleepable.c
> @@ -85,7 +85,7 @@
> .expected_attach_type = BPF_TRACE_RAW_TP,
> .kfunc = "sched_switch",
> .result = REJECT,
> - .errstr = "Only fentry/fexit/fmod_ret, lsm, iter, uprobe, and
> struct_ops programs can be sleepable",
> + .errstr = "Only fentry/fexit/fsession/fmod_ret, lsm, iter, uprobe, and
> struct_ops programs can be sleepable",
> .flags = BPF_F_SLEEPABLE,
> .runs = -1,
> },
> --
> 2.53.0
>
