linux-kernel - Re: Wrong network usage reported by /proc

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 04 May 2009 22:46:01 -0600
From:	Robert Hancock <hancockrwd@...il.com>
To:	Matthias Saou 
	<thias@...m.spam.spam.spam.spam.spam.spam.egg.and.spam.freshrpms.net>
CC:	linux-kernel@...r.kernel.org
Subject: Re: Wrong network usage reported by /proc

Matthias Saou wrote:
> Hi,
> 
> I'm posting here as a last resort. I've got lots of heavily used RHEL5
> servers (2.6.18 based) that are reporting all sorts of impossible
> network usage values through /proc, leading to unrealistic snmp/cacti
> graphs where the outgoing bandwidth used it higher than the physical
> interface's maximum speed.
> 
> For some details and a test script which compares values from /proc
> with values from tcpdump :
> https://bugzilla.redhat.com/show_bug.cgi?id=489541
> 
> The values collected using tcpdump always seem realistic and match the
> values seen on the remote network equipments. So my obvious conclusion
> (but possibly wrong given my limited knowledge) is that something is
> wrong in the kernel, since it's the one exposing the /proc interface.
> 
> I've reproduced what seems to be the same problem on recent kernels,
> including the 2.6.27.21-170.2.56.fc10.x86_64 I'm running right now. The
> simple python script available here allows to see it quite easily :
> https://www.redhat.com/archives/rhelv5-list/2009-February/msg00166.html
> 
>  * I run the script on my Workstation, I have an FTP server enabled
>  * I download a DVD ISO from a remote workstation : The values match
>  * I start ping floods from remote workstations : The values reported
>    by /proc are much higher than the ones reported by tcpdump. I used
>    "ping -s 500 -f myworkstation" from two remote workstations
> 
> If there's anything flawed in my debugging, I'd love to have someone
> point it out to me. TIA to anyone willing to have a look.
> 
> Matthias
> 

There may well be a bug in the kernel you're using, but you'd likely 
have more luck reporting a bug to Red Hat - the RHEL5 kernel is quite 
old and heavily patched and not many LKML people will likely be familiar 
with what RH may have done to it..
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/