Re: [PATCH -stable,5.10 02/10] netfilter: nf_tables: add rescheduling points during loop detection walks

Florian Westphal
2023-07-05T14:31:18Z

Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> From: Florian Westphal <fw@strlen.de>
>
> [ 81ea010667417ef3f218dfd99b69769fe66c2b67 ]
>
> Add explicit rescheduling points during ruleset walk.
>
> Switching to a faster algorithm is possible but this is a much
> smaller change, suitable for nf tree.
>
> Link: https://bugzilla.netfilter.org/show_bug.cgi?id=1460
> Signed-off-by: Florian Westphal <fw@strlen.de>
> Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
> ---
> net/netfilter/nf_tables_api.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
> index e3865f29ae83..3c9292d3f826 100644
> --- a/net/netfilter/nf_tables_api.c
> +++ b/net/netfilter/nf_tables_api.c
> @@ -3164,6 +3164,8 @@ int nft_chain_validate(const struct nft_ctx *ctx, const struct nft_chain *chain)
> if (err < 0)
> return err;
> }
> +
> + cond_resched();
> }
>
> return 0;
> @@ -8506,9 +8508,13 @@ static int nf_tables_check_loops(const struct nft_ctx *ctx,
> break;
> }
> }
> +
> + cond_resched();
> }
>
> list_for_each_entry(set, &ctx->table->sets, list) {
> + cond_resched();
> +
> if (!nft_is_active_next(ctx->net, set))

Nack, this is wrong. Either drop this patch or also pick up
2024439bd5ceb145eeeb428b2a59e9b905153ac3
("netfilter: nf_tables: fix scheduling-while-atomic splat")
I suspect it will cherry-pick without problems.