Date: Fri, 13 Aug 1999 16:22:17 +0100 From: Ben Smithurst <ben@scientia.demon.co.uk> To: Oscar Bonilla <obonilla@fisicc-ufm.edu> Cc: freebsd-questions@FreeBSD.ORG, yurtesen@ispro.net.tr Subject: Re: processes cant be killed? Message-ID: <19990813162217.A14699@lithium.scientia.demon.co.uk> In-Reply-To: <19990811183046.A1967@fisicc-ufm.edu> References: <s7b08646.002@usgs.gov> <19990811183046.A1967@fisicc-ufm.edu>
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Oscar Bonilla wrote:
> kill -9 won't work. Zombie processes cannot be killed. Their address
> spaces have been deallocated so they can't get any signals.
The processes below are not zombies -- there is no "Z" in the status
column.
And I would worry about zombie processes if there are a lot of them; don't
they take up space in the process table? If so, they could limit the
overall number of real processes which can be forked.
In some cases, of course, you may be able to get rid of zombie processes
by killing their parent process, but in some cases it might not be
appropriate to do that.
>>>>> Evren Yurtesen <yurtesen@ispro.net.tr> 8/8/99 12:39:51 PM >>>
>>
>> are these that kind of processes? (well I do not have any clue
>> about what is a zombie process. Where can I learn it from?)
>>
>> root 7991 0.0 0.0 45044 0 p1- D<E - 0:00.00 (pico)
>> root 8026 0.0 0.0 40088 0 p0- DE - 0:00.00 (ee)
This has probably already been answered, but a zombie is a process which
has called exit(), but its parent has not yet called wait4() to pick
up the corpse and dispose of it in an appropriate fashion. The reason
killing its parent will work is that the dead process will lose its
parent, and the system will assign process 1 (init) as its parent, which
will call wait4() appropriately.
But the two above are not zombies, RTFM for ps(1), it will explain what
the letters in the status column mean.
--
Ben Smithurst | PGP: 0x99392F7D
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