From: Pablo Neira Ayuso <pablo@netfilter.org>
To: Gao feng <gaofeng@cn.fujitsu.com>
Cc: netfilter-devel@vger.kernel.org, netdev@vger.kernel.org,
canqunzhang@gmail.com, kaber@trash.net, ebiederm@xmission.com
Subject: Re: [PATCH 19/19] netfilter: gre: fix resource leak when unregister gre proto
Date: Mon, 7 Jan 2013 04:27:11 +0100 [thread overview]
Message-ID: <20130107032711.GA18953@1984> (raw)
In-Reply-To: <50EA3B68.1080001@cn.fujitsu.com>
On Mon, Jan 07, 2013 at 11:05:12AM +0800, Gao feng wrote:
> On 01/07/13 10:59, Gao feng wrote:
> > On 01/07/13 10:38, Pablo Neira Ayuso wrote:
> >> On Mon, Jan 07, 2013 at 03:15:17AM +0100, Pablo Neira Ayuso wrote:
> >>> Hi Gao,
> >>>
> >>> On Mon, Jan 07, 2013 at 09:27:37AM +0800, Gao feng wrote:
> >>>> Hi Pablo,
> >>>>
> >>>> On 01/05/13 11:50, Pablo Neira Ayuso wrote:
> >>>>> Hi Gao,
> >>>>>
> >>>>> On Fri, Dec 28, 2012 at 10:36:46AM +0800, Gao feng wrote:
> >>>>>> Currectly we unregister proto before all conntrack entries of
> >>>>>> this proto being destroyed. so in function destroy_conntrack
> >>>>>> we can't find proper l4proto to call l4proto->destroy.
> >>>>>> this will cause resource leak.
> >>>>>
> >>>>> Good catch.
> >>>>>
> >>>>> But better to remove the entries before unregistering the protocol
> >>>>> tracker, so l4proto->destroy is always called.
> >>>>>
> >>>>
> >>>> I think the reason we unregister proto before remove all entries
> >>>> is to avoid new entry for this protocol being created.
> >>>>
> >>>> If we remove all contrack entries before unregistration, there maybe
> >>>> some new entries being created between nf_ct_iterate_cleanup and
> >>>> nf_conntrack_l4proto_unregister_net.this will cause some terrible things.
> >>>
> >>> Leaks are less likely to happen, but may well still happen while
> >>> racing with protocol removal, agreed.
> >>>
> >>>> SO I think we should make proto unavailable first,remove all entries next,
> >>>> and remove proto from nf_ct_protos arrays finally.
> >>>
> >>> Your proposal adds a branch in the packet path to fix an issue that is
> >>> specific of the GRE protocol tracker. In the current code, this fixes
> >>> the memory leak while removing the nf_conntrack_proto_gre module,
> >>> which is a rare operation.
> >>>
> >>> We have to come with a less intrusive solution.
> >>
> >> Wait. The existing code is calling nf_ct_gre_keymap_flush in
> >> proto_gre_net_exit path, so those keymap objects are not leaked.
> >
> > Agree, it looks like nf_ct_gre_keymap_flush is added to solve this
> > problem.
> >
> > Please ignore this patch.
>
> I mean ignore the codes of gre part.
> I still think nf_ct_iterate_cleanup doesn't make sure all entries being
> destroyed.
There is another round of nf_ct_iterate cleanup in
nf_conntrack_cleanup_net. So I don't see any possible leak so far. Let
me know if you find anything.
Thanks.
next prev parent reply other threads:[~2013-01-07 3:27 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-28 2:36 [PATCH 01/19] netfilter: move nf_conntrack initialize out of pernet operations Gao feng
2012-12-28 2:36 ` [PATCH 02/19] netfilter: expect: move initial codes out of pernet_operations Gao feng
2012-12-28 2:36 ` [PATCH 03/19] netfilter: acct: " Gao feng
2012-12-28 2:36 ` [PATCH 04/19] netfilter: tstamp: " Gao feng
2012-12-28 2:36 ` [PATCH 05/19] netfilter: ecache: " Gao feng
2012-12-28 2:36 ` [PATCH 06/19] netfilter: timeout: " Gao feng
2012-12-28 2:36 ` [PATCH 07/19] netfilter: helper: " Gao feng
2012-12-28 2:36 ` [PATCH 08/19] netfilter: proto: " Gao feng
2012-12-28 2:36 ` [PATCH 09/19] netfilter: l3proto: prepare reworking l3proto support for netns Gao feng
2012-12-28 2:36 ` [PATCH 10/19] netfilter: ipv4: register ipv4 in module_init Gao feng
2012-12-28 2:36 ` [PATCH 10/19] netfilter: ipv4: register l3proto " Gao feng
2012-12-28 2:36 ` [PATCH 11/19] netfilter: ipv6: register l3proto ipv6 " Gao feng
2012-12-28 2:36 ` [PATCH 12/19] netfilter: l4proto: prepare reworking l4proto support for netns Gao feng
2012-12-28 2:36 ` [PATCH 13/19] netfilter: ipv4: move registration codes out of pernet_operations Gao feng
2012-12-28 2:36 ` [PATCH 14/19] netfilter: ipv6: " Gao feng
2012-12-28 2:36 ` [PATCH 15/19] netfilter: sctp: " Gao feng
2012-12-28 2:36 ` [PATCH 16/19] netfilter: udplite: " Gao feng
2012-12-28 2:36 ` [PATCH 17/19] netfilter: dccp: " Gao feng
2012-12-28 2:36 ` [PATCH 18/19] netfilter: gre: " Gao feng
2012-12-28 2:36 ` [PATCH 19/19] netfilter: gre: fix resource leak when unregister gre proto Gao feng
2013-01-05 3:50 ` Pablo Neira Ayuso
2013-01-07 1:27 ` Gao feng
2013-01-07 2:15 ` Pablo Neira Ayuso
2013-01-07 2:38 ` Pablo Neira Ayuso
2013-01-07 2:59 ` Gao feng
2013-01-07 3:05 ` Gao feng
2013-01-07 3:27 ` Pablo Neira Ayuso [this message]
2013-01-07 3:43 ` Gao feng
2012-12-28 3:52 ` [PATCH 01/19] netfilter: move nf_conntrack initialize out of pernet operations canqun zhang
2012-12-28 4:48 ` Eric W. Biederman
2012-12-28 5:32 ` canqun zhang
2012-12-28 6:00 ` Eric W. Biederman
2012-12-28 11:58 ` Pablo Neira Ayuso
2012-12-28 7:16 ` Gao feng
2012-12-28 8:48 ` canqun zhang
2013-01-10 1:03 ` Gao feng
2013-01-10 16:41 ` Pablo Neira Ayuso
2013-01-11 1:01 ` Gao feng
2013-01-13 15:07 ` Pablo Neira Ayuso
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