From: Florian Westphal <fw@strlen.de>
To: Andrey Vagin <avagin@openvz.org>
Cc: linux-kernel@vger.kernel.org, netfilter-devel@vger.kernel.org,
netfilter@vger.kernel.org, coreteam@netfilter.org,
netdev@vger.kernel.org, vvs@parallels.com,
Pablo Neira Ayuso <pablo@netfilter.org>,
Patrick McHardy <kaber@trash.net>,
Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>,
"David S. Miller" <davem@davemloft.net>
Subject: Re: [PATCH] netfilter: nf_conntrack: reserve two bytes for nf_ct_ext->len
Date: Thu, 27 Mar 2014 16:50:33 +0100 [thread overview]
Message-ID: <20140327155033.GF21741@breakpoint.cc> (raw)
In-Reply-To: <1395934354-13226-1-git-send-email-avagin@openvz.org>
Andrey Vagin <avagin@openvz.org> wrote:
> "len" contains sizeof(nf_ct_ext) and size of extensions. In a worst
> case it can contain all extensions. Bellow you can find sizes for all
> types of extensions. Their sum is definitely bigger than 256.
>
> nf_ct_ext_types[0]->len = 24
> nf_ct_ext_types[1]->len = 32
> nf_ct_ext_types[2]->len = 24
> nf_ct_ext_types[3]->len = 32
> nf_ct_ext_types[4]->len = 152
Guess its the timer in the ecache extension (with LOCKDEP on probably).
I'll submit a patch to get rid of that shortly.
I think your patch is fine because the 'no timer
in ecache extension' change is quite large, needs review/stress testing
etc and is inapropriate for stable tree anyway.
> I have seen "len" up to 280 and my host has crashes w/o this patch.
ecache is 24 bytes without that timer, should be < 256 in total for
all extensions.
I think BUILD_BUG_ON test would be nice.
next prev parent reply other threads:[~2014-03-27 15:50 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-27 15:32 [PATCH] netfilter: nf_conntrack: reserve two bytes for nf_ct_ext->len Andrey Vagin
2014-03-27 15:45 ` Patrick McHardy
2014-03-27 20:06 ` [PATCH] netfilter: nf_conntrack: reserve two bytes for nf_ct_ext->len (v2) Andrey Vagin
2014-03-27 15:50 ` Florian Westphal [this message]
2014-03-27 16:01 ` [PATCH] netfilter: nf_conntrack: reserve two bytes for nf_ct_ext->len Patrick McHardy
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