On Fri, Apr 14, 2017 at 01:42:04AM +0200, Pablo Neira Ayuso wrote:
> On Fri, Apr 14, 2017 at 07:37:50AM +0800, Liping Zhang wrote:
> > Hi Pablo,
> >
> > 2017-04-14 7:16 GMT+08:00 Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>:
> > [...]
> > >> #ifndef _NF_CONNTRACK_HELPER_H
> > >> #define _NF_CONNTRACK_HELPER_H
> > >> +#include <linux/refcount.h>
> > >> #include <net/netfilter/nf_conntrack.h>
> > >> #include <net/netfilter/nf_conntrack_extend.h>
> > >> #include <net/netfilter/nf_conntrack_expect.h>
> > >> @@ -26,6 +27,7 @@ struct nf_conntrack_helper {
> > >> struct hlist_node hnode; /* Internal use. */
> > >>
> > >> char name[NF_CT_HELPER_NAME_LEN]; /* name of the module */
> > >> + refcount_t refcnt;
> > >
> > > Should this new refcnt; thing be in the new struct nfnl_cthelper?
> > >
> > > I think this refcount is only required by the userspace helper
> > > infrastructure, not existing in-kernel helpers.
> > >
> > > I think like that we can skip patch 1/2 in this series.
> >
> > We must call nf_conntrack_helper_try_module_get to get the helper,
> > either it is userspace or in-kernel helpers. Also the caller didn't care
> > the helpers is userspace or in-kernel, so I think introducing the
> > nf_conntrack_helper_put is necessary.
> >
> > Also, this path set is prepared for per-net helper. For in-kernel helpers,
> > we will still need to kmemdup the original one. I mean:
> > helper = kmemdup(ftp_helper);
> > helper->expect_policy = kmemdup(ftp_exp_policy);
> > nf_conntrack_helper_register(net, helper);
> >
> > And similar to nfnetlink_cttimeout, for net_exit, we should:
> > list_for_each_entry_safe()
> > unregister_helper();
> > if (refcount_dec_and_test(&cur->refcnt))
> > call_rcu(free_xxx);
> >
> > For nf_conntrack_helper_put, we should:
> > if (refcount_dec_and_test(&cur->refcnt))
> > call_rcu(free_xxx);
> >
> > So I think put this "refcount_t refcnt" to struct nf_conntrack_helper
> > is better.
>
> OK, please resubmit target to nf-next. It's too late for patches
> already for nf, we're at -rc6 and this problem has been there for a
> bit of time. So waiting a bit more to get this fixed should be OK.
BTW, you may have to wait until dependencies (ie. patches in nf.git)
show up in nf-next.git, it may take a little while to propagate.
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