bpf_mark_chain_precision
int bpf_mark_chain_precision(struct bpf_verifier_env *env,
err = bpf_mark_chain_precision(env, cur, -1, changed);
return bpf_mark_chain_precision(env, env->cur_state, regno, NULL);
return bpf_mark_chain_precision(env, starting_state, -1, NULL);