crash —— 输出属于同一个进程的所有线程

/* ok, now we should be set up.. */
  p->pid = pid_nr(pid);
  if (clone_flags & CLONE_THREAD) {
    p->group_leader = current->group_leader;
    p->tgid = current->tgid;
  } else {
    p->group_leader = p;
    p->tgid = p->pid;
  }
  ......
  if (likely(p->pid)) {
    ptrace_init_task(p, (clone_flags & CLONE_PTRACE) || trace);
    init_task_pid(p, PIDTYPE_PID, pid);
    if (thread_group_leader(p)) {
      init_task_pid(p, PIDTYPE_TGID, pid);
      init_task_pid(p, PIDTYPE_PGID, task_pgrp(current));
      init_task_pid(p, PIDTYPE_SID, task_session(current));
      if (is_child_reaper(pid)) {
        ns_of_pid(pid)->child_reaper = p;
        p->signal->flags |= SIGNAL_UNKILLABLE;
      }
      p->signal->shared_pending.signal = delayed.signal;
      p->signal->tty = tty_kref_get(current->signal->tty);
      /*
       * Inherit has_child_subreaper flag under the same
       * tasklist_lock with adding child to the process tree
       * for propagate_has_child_subreaper optimization.
       */
      p->signal->has_child_subreaper = p->real_parent->signal->has_child_subreaper ||
               p->real_parent->signal->is_child_subreaper;
      list_add_tail(&p->sibling, &p->real_parent->children);
      list_add_tail_rcu(&p->tasks, &init_task.tasks);
      attach_pid(p, PIDTYPE_TGID);
      attach_pid(p, PIDTYPE_PGID);
      attach_pid(p, PIDTYPE_SID);
      __this_cpu_inc(process_counts);
    } else {
      current->signal->nr_threads++;
      current->signal->quick_threads++;
      atomic_inc(&current->signal->live);
      refcount_inc(&current->signal->sigcnt);
      task_join_group_stop(p);
      list_add_tail_rcu(&p->thread_group,
            &p->group_leader->thread_group);
      list_add_tail_rcu(&p->thread_node,
            &p->signal->thread_head);
    }
    attach_pid(p, PIDTYPE_PID);
    nr_threads++;
  }