Messages in this thread | ![/](/images/icornerl.gif) | | Date | Mon, 18 Dec 2023 19:06:40 +0000 | From | Simon Horman <> | Subject | Re: [RFC nf-next v2 1/2] netfilter: bpf: support prog update |
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On Mon, Dec 18, 2023 at 12:18:20PM +0800, D. Wythe wrote: > From: "D. Wythe" <alibuda@linux.alibaba.com> > > To support the prog update, we need to ensure that the prog seen > within the hook is always valid. Considering that hooks are always > protected by rcu_read_lock(), which provide us the ability to > access the prog under rcu. > > Signed-off-by: D. Wythe <alibuda@linux.alibaba.com>
...
> @@ -26,8 +17,20 @@ struct bpf_nf_link { > struct net *net; > u32 dead; > const struct nf_defrag_hook *defrag_hook; > + struct rcu_head head; > }; > > +static unsigned int nf_hook_run_bpf(void *bpf_link, struct sk_buff *skb, > + const struct nf_hook_state *s) > +{ > + const struct bpf_nf_link *nf_link = bpf_link; > + struct bpf_nf_ctx ctx = { > + .state = s, > + .skb = skb, > + }; > + return bpf_prog_run(rcu_dereference(nf_link->link.prog), &ctx);
Hi,
AFAICT nf_link->link.prog isn't annotated as __rcu, so perhaps rcu_dereference() is not correct here?
In any case, sparse seems a bit unhappy:
.../nf_bpf_link.c:31:29: error: incompatible types in comparison expression (different address spaces): .../nf_bpf_link.c:31:29: struct bpf_prog [noderef] __rcu * .../nf_bpf_link.c:31:29: struct bpf_prog *
> +} > + > #if IS_ENABLED(CONFIG_NF_DEFRAG_IPV4) || IS_ENABLED(CONFIG_NF_DEFRAG_IPV6) > static const struct nf_defrag_hook * > get_proto_defrag_hook(struct bpf_nf_link *link,
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