pktgen_thread_worker() doesn't need to wait for kthread_stop(), it
can simply exit. Just pktgen_create_thread() and pg_net_exit() should
do get_task_struct()/put_task_struct(). kthread_stop(dead_thread) is
fine.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
        pr_debug("%s removing thread\n", t->tsk->comm);
        pktgen_rem_thread(t);
 
-       /* Wait for kthread_stop */
-       for (;;) {
-               set_current_state(TASK_INTERRUPTIBLE);
-               if (kthread_should_stop())
-                       break;
-               schedule();
-       }
-       __set_current_state(TASK_RUNNING);
-
        return 0;
 }
 
        }
 
        t->net = pn;
+       get_task_struct(p);
        wake_up_process(p);
        wait_for_completion(&t->start_done);
 
                t = list_entry(q, struct pktgen_thread, th_list);
                list_del(&t->th_list);
                kthread_stop(t->tsk);
+               put_task_struct(t->tsk);
                kfree(t);
        }