public inbox for linux-kernel@vger.kernel.org
 help / color / mirror / Atom feed
From: Nuno Silva <nuno.silva@vgertech.com>
To: Patryk Jakubowski <patrics@interia.pl>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Invisible threads in 2.6.9
Date: Wed, 06 Oct 2004 04:08:12 +0100	[thread overview]
Message-ID: <4163619C.4070600@vgertech.com> (raw)
In-Reply-To: <41630B2C.5020709@interia.pl>

Patryk Jakubowski wrote:

...

> When I run it, the system (predictably) goes to ~100% CPU utilization,
> but there seems to be no way to find out who is hogging the CPU with
> top(1), ps(1), or anything else. All they can show is the main thread in
> zombie state, consuming 0% CPU.
> 
> Is this correct behaviour of linux?
> Would not this allow user space programs to hide running executions?
> This could be an opportunity for spyware to infect the machine and hide
> itself perhaps? Hope I'm wrong here!
> 
> If this is the bug in kernel (procfs?)  I can give you my configuration
> and resulting behaviour.

Yes, that's the new method trojans are using to hide tasks... No need to 
install complicated kernel modules anymore :-)

More seriously: That's a problem with current procps utils... They just 
don't show them. I can't complain too much because I'm not doing any 
code, but it would be nice to have a working top...

As a workaround, to at least see the threads without inspecting /proc 
directly, you can use the 'm' and 'H' flags to ps, i.e.

$ ps auwxH

Regards,
Nuno Silva


  reply	other threads:[~2004-10-06  3:08 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <S268296AbUJDTjb/20041004193948Z+2396@vger.kernel.org>
2004-10-05 20:59 ` Invisible threads in 2.6.9 Patryk Jakubowski
2004-10-06  3:08   ` Nuno Silva [this message]
2004-10-06  7:50     ` Michal Schmidt
2004-10-06 10:14       ` Patryk Jakubowski
     [not found]         ` <20041006110721.GC4380@vana.vc.cvut.cz>
2004-10-06 11:36           ` Patryk Jakubowski
2004-10-06 14:58             ` Chris Friesen
2004-10-07  0:21 Albert Cahalan

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=4163619C.4070600@vgertech.com \
    --to=nuno.silva@vgertech.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=patrics@interia.pl \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox