+ rcu_read_lock();
+ helper = __nf_ct_helper_find(rtuple);
+ if (helper) {
+ help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
+ if (help == NULL) {
+ rcu_read_unlock();
+ err = -ENOMEM;
+ goto err;
+ }
+ /* not in hash table yet so not strictly necessary */
+ rcu_assign_pointer(help->helper, helper);
+ }
+