From a5a6b29a700fda1dd766cc42dde2cbba9b19f470 Mon Sep 17 00:00:00 2001 From: KaFai Wan Date: Thu, 24 Jul 2025 23:14:51 +0800 Subject: bpf: Show precise rejected function when attaching fexit/fmod_ret to __noreturn functions 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 Signed-off-by: KaFai Wan Acked-by: Yafang Shao Acked-by: Yonghong Song Link: https://lore.kernel.org/r/20250724151454.499040-2-kafai.wan@linux.dev Signed-off-by: Alexei Starovoitov --- kernel/bpf/verifier.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index e50d3d43be67..4bf7392fd2c3 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -23985,7 +23985,8 @@ 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; } -- cgit v1.2.3