release_reference
WARN_ON_ONCE(release_reference(env, st->ref_obj_id));
err = release_reference(env, meta.ref_obj_id);
err = release_reference(env, reg->ref_obj_id);
err = release_reference(env, release_ref_obj_id);
static int release_reference(struct bpf_verifier_env *env, int ref_obj_id);
WARN_ON_ONCE(release_reference(env, ref_obj_id));