gdb 可以附加一个僵尸进程（<defunct>）吗？

Question

我有一个作为僵尸进程运行的程序。我想调试它。但是我得到了一个 gdb 错误。

mobile:/usr/local/ads5/bin# ps axf | grep ads_resolver
 5583 pts/2    S      0:00 ./ads_resolver main.cfg
 5584 pts/2    Zl     0:36  \_ [ads_resolver] <defunct>

mobile:/usr/local/ads5/bin# gdb ads_resolver 5584
GNU gdb 6.8-debian
Copyright (C) 2008 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "i486-linux-gnu"...
Attaching to program: /usr/local/ads5/bin/ads_resolver, process 5584
ptrace: Operation not permitted.
/usr/local/ads5/bin/5584: No such file or directory.
(gdb) info threads
No registers.

有我的代码创建了僵尸进程：

template < class T>
int Monitor < T >::Start()
{
    pid_t pid;
    pid = fork();
    if(pid == 0)
    {
        IgnoreSignal::IgnoreDaemon();
        signal(SIGCHLD,Monitor<T>::ReStart);

        pid = fork();
        if(pid == 0)
        {
            IgnoreSignal::IgnoreAll();
            T worker;
            worker.Run();
        }
        while(1)
        {
            sleep(60);
        }
    }
    return 0; 
}

Answer 1

僵尸进程已完成执行，但操作系统正在等待父进程调用 wait()。这只是一个状态或标志 - 就可执行性而言，该进程不再“存在”。

因此，gdb 不可能连接到不再执行的进程，包括僵尸进程。

http://en.wikipedia.org/wiki/Zombie_process