With this change, we know the precise rejected function name when attaching fexit/fmod_ret to __noreturn functions from log.
$ ./fexit libbpf: prog 'fexit': BPF program load failed: -EINVAL libbpf: prog 'fexit': -- BEGIN PROG LOAD LOG -- Attaching fexit/fmod_ret to __noreturn function 'do_exit' is rejected.
Suggested-by: Leon Hwang leon.hwang@linux.dev Signed-off-by: KaFai Wan kafai.wan@linux.dev Acked-by: Yafang Shao laoar.shao@gmail.com Acked-by: Yonghong Song yonghong.song@linux.dev --- kernel/bpf/verifier.c | 3 ++- tools/testing/selftests/bpf/progs/fexit_noreturns.c | 2 +- 2 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index e2fcea860755..00d287814f12 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -23946,7 +23946,8 @@ static int check_attach_btf_id(struct bpf_verifier_env *env) } else if ((prog->expected_attach_type == BPF_TRACE_FEXIT || prog->expected_attach_type == BPF_MODIFY_RETURN) && btf_id_set_contains(&noreturn_deny, btf_id)) { - verbose(env, "Attaching fexit/fmod_ret to __noreturn functions is rejected.\n"); + verbose(env, "Attaching fexit/fmod_ret to __noreturn function '%s' is rejected.\n", + tgt_info.tgt_name); return -EINVAL; }
diff --git a/tools/testing/selftests/bpf/progs/fexit_noreturns.c b/tools/testing/selftests/bpf/progs/fexit_noreturns.c index 54654539f550..b1c33d958ae2 100644 --- a/tools/testing/selftests/bpf/progs/fexit_noreturns.c +++ b/tools/testing/selftests/bpf/progs/fexit_noreturns.c @@ -8,7 +8,7 @@ char _license[] SEC("license") = "GPL";
SEC("fexit/do_exit") -__failure __msg("Attaching fexit/fmod_ret to __noreturn functions is rejected.") +__failure __msg("Attaching fexit/fmod_ret to __noreturn function 'do_exit' is rejected.") int BPF_PROG(noreturns) { return 0;