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SubjectRe: [PATCH NETFILTER] netfilter: gre: nf_ct_gre_keymap_flush() removal
Vasily Averin <vvs@virtuozzo.com> wrote:
> nf_ct_gre_keymap_flush() is useless.
> It is called from nf_conntrack_cleanup_net_list() only and tries to remove
> nf_ct_gre_keymap entries from pernet gre keymap list. Though:
> a) at this point the list should already be empty, all its entries were
> deleted during the conntracks cleanup, because
> nf_conntrack_cleanup_net_list() executes nf_ct_iterate_cleanup(kill_all)
> before nf_conntrack_proto_pernet_fini():
> nf_conntrack_cleanup_net_list
> +- nf_ct_iterate_cleanup
> | nf_ct_put
> | nf_conntrack_put
> | nf_conntrack_destroy
> | destroy_conntrack
> | destroy_gre_conntrack
> | nf_ct_gre_keymap_destroy
> `- nf_conntrack_proto_pernet_fini
> nf_ct_gre_keymap_flush
>
> b) Let's say we find that the keymap list is not empty. This means netns
> still has a conntrack associated with gre, in which case we should not free
> its memory, because this will lead to a double free and related crashes.
> However I doubt it could have gone unnoticed for years, obviously
> this does not happen in real life. So I think we can remove
> both nf_ct_gre_keymap_flush() and nf_conntrack_proto_pernet_fini().

Acked-by: Florian Westphal <fw@strlen.de>

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