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 migrate_disable() from log.
$ ./fentry
libbpf: prog 'migrate_disable': BPF program load failed: -EINVAL
libbpf: prog 'migrate_disable': -- BEGIN PROG LOAD LOG --
Attaching tracing programs to function 'migrate_disable' is rejected.
Suggested-by: Leon Hwang <leon.hwang@xxxxxxxxx>
Signed-off-by: KaFai Wan <kafai.wan@xxxxxxxxx>
---
kernel/bpf/verifier.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 00d287814f12..c24c0d57e595 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -23942,6 +23942,8 @@ 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) &&
--
2.43.0
