diff options
| author |   KaFai Wan <kafai.wan@linux.dev> | 2025-07-24 23:14:52 +0800 |
|---|---|---|
| committer |   Alexei Starovoitov <ast@kernel.org> | 2025-07-28 19:39:29 -0700 |
| commit | 863aab3d4dcdfffa5cf0e0795c526dadca65be7a (patch) | |
| tree | a49b2b3392ba9d718b37b7781031a661383fa277 | |
| parent | bpf: Show precise rejected function when attaching fexit/fmod_ret to __noreturn functions (diff) | |
| download | wireguard-linux-863aab3d4dcdfffa5cf0e0795c526dadca65be7a.tar.xz wireguard-linux-863aab3d4dcdfffa5cf0e0795c526dadca65be7a.zip | |
bpf: Add log for attaching tracing programs to functions in deny list
Show the rejected function name when attaching tracing programs to
functions in deny list.
With this change, we know why tracing programs can't attach to functions
like __rcu_read_lock() from log.
$ ./fentry
libbpf: prog '__rcu_read_lock': BPF program load failed: -EINVAL
libbpf: prog '__rcu_read_lock': -- BEGIN PROG LOAD LOG --
Attaching tracing programs to function '__rcu_read_lock' 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>
Link: https://lore.kernel.org/r/20250724151454.499040-3-kafai.wan@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
| -rw-r--r-- | kernel/bpf/verifier.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 4bf7392fd2c3..399f03e62508 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -23981,6 +23981,8 @@ static int check_attach_btf_id(struct bpf_verifier_env *env) return ret; } else if (prog->type == BPF_PROG_TYPE_TRACING && btf_id_set_contains(&btf_id_deny, btf_id)) { + verbose(env, "Attaching tracing programs to function '%s' is rejected.\n", + tgt_info.tgt_name); return -EINVAL; } else if ((prog->expected_attach_type == BPF_TRACE_FEXIT || prog->expected_attach_type == BPF_MODIFY_RETURN) && |