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From: "Sven Köhler" <skoehler@upb.de>
To: linux-kernel@vger.kernel.org
Subject: Re: cat /dev/hdb > /dev/null DoS
Date: Thu, 08 Apr 2004 12:36:11 +0200	[thread overview]
Message-ID: <c539ur$h5e$1@sea.gmane.org> (raw)
In-Reply-To: <20040408085518.B4607@beton.cybernet.src>

> I did cat /dev/hdb > /dev/null and after a while (5 minutes),
> the system went totally unresponsive:
> 
> 1) man top takes 3 minutes to display man page
> 2) Switching between console and X takes also a couple of minutes
> 3) top shows this:
> 
> Cpu(s):  1.4% us,  1.4% sy,  0.0% ni,  0.0% id,  0.0% wa, 97.3% hi,  0.0% si

i guess you have DMA enabled on /dev/hdb. I would expect, that the 
system is at least 50% idle


  reply	other threads:[~2004-04-08 10:36 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-04-08  8:55 cat /dev/hdb > /dev/null DoS Karel Kulhavý
2004-04-08 10:36 ` Sven Köhler [this message]
2004-04-09  0:10   ` Sven Köhler
2004-04-09  6:47     ` Denis Vlasenko

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