list_for_each (runp, &stack_used)
list_for_each (runp, &__stack_user)
  list_for_each (runp, &stack_used)    {      struct pthread *curp;      curp = list_entry (runp, struct pthread, list);      if (curp->tid == tid)	{	  result = curp;	  goto out;	}    }