Re: [PATCH RFC bpf-next v3 06/16] bpf/helpers: introduce bpf_timer_set_sleepable_cb() kfunc

On Wed, 2024-02-21 at 17:25 +0100, Benjamin Tissoires wrote:

[...]

@@ -12120,6 +12137,16 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, } }

• if (is_async_callback_calling_kfunc(meta.func_id)) {

I think that it's better to check specific kfunc id here:

meta.func_id == special_kfunc_list[KF_bpf_timer_set_sleepable_cb_impl]

In case if some new async callback calling kfunc would be added, for which set_timer_callback_state() won't be correct.

• err = push_callback_call(env, insn, insn_idx, meta.subprogno,
  

• 			 set_timer_callback_state);
  

• if (err) {
  

• 	verbose(env, "kfunc %s#%d failed callback verification\n",
  

• 		func_name, meta.func_id);
  

• 	return err;
  

• }
  

• }
• rcu_lock = is_kfunc_bpf_rcu_read_lock(&meta); rcu_unlock = is_kfunc_bpf_rcu_read_unlock(&meta);