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iptables/vmalloc issues on alchemy (revisited)

To: <>
Subject: iptables/vmalloc issues on alchemy (revisited)
From: "Christi Garvin" <>
Date: Thu, 5 Jan 2006 08:15:13 -0800
Cc: <>
Importance: normal
Original-recipient: rfc822;
Priority: normal
Thread-index: AcYSEzU4znvuLfZaQv6+6AVntEqEWg==
Thread-topic: iptables/vmalloc issues on alchemy (revisited)
This issue was reported on this mailing list back in April '05....
On Tue, 2005-04-26 at 10:43 +0200, Herbert Valerio Riedel wrote:
> ... 
> The problem seems to be so far, that when modifying the iptables
> structures by adding/flushing the rules, a state can be reached sooner
> or later (indeterministic! smells like race) where the data structure
> becomes invalid (although there are checks in the kernel which would
> prevent that); the result is either ip_tables.c:ipt_do_tables() causing
> an oops due to bad pointer dereferencing (or the kernel freezing w/o
> further notice at all), or the iptables tool being unable to
> retrieve/modify the rules from the kernel (and getting ENOMEM/EINVAL) or
> simply segfaulting due to other inconsistencies with the data...
it appears the problem was found...
On Wed, 2005-04-27 at 15:06 -0400, Dan Malek wrote:
> Oh wait ....  I found a bug a while ago from someone trying to load
> large modules.  There is a problem if the kernel grows to need
> additional PTE tables, the top level pointers don't get propagated
> correctly and subsequent access by a thread that didn't actually
> do the allocation would fail.  I'm looking into this, including your
> past message about 64-bit PTEs.
and possibly fixed:
> From: Dan Malek [] 
> Sent: Thursday, April 28, 2005 3:57 PM
> Subject: Re: iptables/vmalloc issues on alchemy
> I've just been talking about 2.6, so "long time ago" can't be
> that long :-)  I have the updates to the exception handler so
> the PTEs get loaded correctly, that's on the way.  I think 2.4
> should be OK if anyone is using that.
I am encountering this same problem with 2.6.11 and iptables 1.2.11, 
and I've searched for an appropriate patch/fix, and cannot find one....
Can you tell me if this has been fixed, and if so, point me in the
direction of the patch?
christi garvin
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