T1                     T2

  t0->terminate();
    lock();
    read ID;
    pthread_cancel(ID);
    unlock()
                         t0->terminate();
                           lock();
                           read ID;
    (OS thread finishes)
  t3->start();
    (creates a new OS
     thread with same ID)
                           pthread_cancel(ID); // cancels new t3!
                           unlock();