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. -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
