Mailing List Archive: Gentoo: Security

kill zombie process

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skler at freaknet

Jan 19, 2005, 12:50 AM

Post #1 of 6 (786 views)
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kill zombie process

when i run ps aux | grep Z on one desktop i have this output:

skler [at] noma skler $ ps aux | grep Z
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
skler 2756 0.0 0.0 0 0 ? Z Jan17 0:00
[firefox-bin] <defunct>
skler 10105 0.0 0.0 0 0 ? Z Jan17 0:00 [netstat]
<defunct>
skler 12854 0.0 0.0 0 0 ? Z Jan17 0:00 [netstat]
<defunct>
skler 22774 0.0 0.0 0 0 ? Z 08:37 0:00 [netstat]
<defunct>
skler 23213 0.0 0.0 0 0 ? Z 08:48 0:00 [play]
<defunct>

how can i kill this processes?
--
Linux registered user: #334564

[ Mauro a.k.a. skler - Freaknet Medialab Catania ]
[ @: skler (at) freaknet.org - W3: http://www.sklerlab.net ]
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martin.zwickel at technotrend

Jan 19, 2005, 2:02 AM

Post #2 of 6 (760 views)
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Re: kill zombie process [In reply to]

On Wed, 19 Jan 2005 08:50:52 +0100
skler <skler [at] freaknet> bubbled:

>
> when i run ps aux | grep Z on one desktop i have this output:
>
> skler [at] noma skler $ ps aux | grep Z
> USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
> skler 2756 0.0 0.0 0 0 ? Z Jan17 0:00
> [firefox-bin] <defunct>
> skler 10105 0.0 0.0 0 0 ? Z Jan17 0:00
> [netstat]<defunct>
> skler 12854 0.0 0.0 0 0 ? Z Jan17 0:00
> [netstat]<defunct>
> skler 22774 0.0 0.0 0 0 ? Z 08:37 0:00
> [netstat]<defunct>
> skler 23213 0.0 0.0 0 0 ? Z 08:48 0:00 [play]
> <defunct>
>
> how can i kill this processes?

do a "ps fax" an kill the parent process.

netstat looks like mozilla/firefox. that is a normal behaviour:

870 ? Ss 0:00 \_ /bin/bash /usr/bin/mozilla
880 ? S 14:17 | \_ /usr/lib/mozilla/mozilla-bin
884 ? S 0:00 | \_ /usr/lib/mozilla/mozilla-bin
885 ? S 0:04 | | \_ /usr/lib/mozilla/mozilla-bin
886 ? S 0:04 | | \_ /usr/lib/mozilla/mozilla-bin
9022 ? Z 0:00 | \_ [netstat] <defunct>

Regards,
Martin

--
MyExcuse:
According to Microsoft, it's by design

Martin Zwickel <martin.zwickel [at] technotrend>
Research & Development

TechnoTrend AG <http://www.technotrend.de>

swift at gentoo

Jan 19, 2005, 2:10 AM

Post #3 of 6 (759 views)
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Re: kill zombie process [In reply to]

On Wed, Jan 19, 2005 at 08:50:52AM +0100, skler wrote:
> when i run ps aux | grep Z on one desktop i have this output:
>
> skler [at] noma skler $ ps aux | grep Z
[... snip zombie processes ...]
>
> how can i kill this processes?

A zombie process isn't a process, it's an entry in the process table but
consumes no resources. A zombie process exists when the process itself has
died while the parent process is not notified about it's disappearance (i.e.
no wait() or similar system call).

So the solution to remove these zombie processes is to inform the parent
about the silent death of it's childs (some processes can be notified
through a signal) or by exiting the parent (or killing it).

So in short, find out who the parent of the zombie process is (with tools
such as pstree and such this shouldn't be too difficult) and kill it (if
that's feasible).

But again, it's just cosmetic, it doesn't take any resources (apart from a
single entry in the process table).

Wkr,
Sven Vermeulen

--
Documentation & PR project leader

The Gentoo Project <<< http://www.gentoo.org >>>

chantra at dotgeek

Jan 19, 2005, 2:18 AM

Post #4 of 6 (752 views)
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Re: kill zombie process [In reply to]

Sven Vermeulen wrote:

>> On Wed, Jan 19, 2005 at 08:50:52AM +0100, skler wrote:
>>
>>
>>> when i run ps aux | grep Z on one desktop i have this output:
>>>
>>> skler [at] noma skler $ ps aux | grep Z
>>>
>>
>> [... snip zombie processes ...]
>>
>>
>>> how can i kill this processes?
>>>
>>
>>
>> A zombie process isn't a process, it's an entry in the process table but
>> consumes no resources. A zombie process exists when the process
>> itself has
>> died while the parent process is not notified about it's
>> disappearance (i.e.
>> no wait() or similar system call).
>>
>> So the solution to remove these zombie processes is to inform the parent
>> about the silent death of it's childs (some processes can be notified
>> through a signal) or by exiting the parent (or killing it).
>> So in short, find out who the parent of the zombie process is (with
>> tools
>> such as pstree and such this shouldn't be too difficult) and kill it (if
>> that's feasible).
>> But again, it's just cosmetic, it doesn't take any resources (apart
>> from a
>> single entry in the process table).
>>
>>
>>
>
> It doesn't take any ressources, but it can be a pain when such a
> process is "xmms" for instance. As a matter of fact, xmms won't create
> a new windows if another xmms process is opened.
> regards,
> ptitman
>
>> Wkr,
>> Sven Vermeulen
>>
>>
>>

--
gentoo-security [at] gentoo mailing list

vapier at gentoo

Jan 19, 2005, 7:20 AM

Post #5 of 6 (758 views)
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Re: kill zombie process [In reply to]

On Wednesday 19 January 2005 04:18 am, manu wrote:
> > It doesn't take any ressources, but it can be a pain when such a
> > process is "xmms" for instance. As a matter of fact, xmms won't create
> > a new windows if another xmms process is opened.

i have a bug on my desktop atm where there's always a zombie xmms process, but
it doesnt affect killing / starting of a new xmms

and no, i dont have the 'multiple windows' (or whatever it's called) feature
enabled
-mike

--
gentoo-security [at] gentoo mailing list

pauldv at gentoo

Feb 18, 2005, 3:25 AM

Post #6 of 6 (754 views)
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Re: kill zombie process [In reply to]

On Wednesday 19 January 2005 10:10, Sven Vermeulen wrote:
>
> A zombie process isn't a process, it's an entry in the process table
> but consumes no resources. A zombie process exists when the process
> itself has died while the parent process is not notified about it's
> disappearance (i.e. no wait() or similar system call).

In most cases the problem is caused by the parent not correctly handling
these messages, and as such the process stays in the table so that the
parent can still retrieve it's exit code (which probably will never
happen)

Paul

--
Paul de Vrieze
Gentoo Developer
Mail: pauldv [at] gentoo
Homepage: http://www.devrieze.net

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