linux-kernel - Re: [PATCH bpf v5 1/3] bpf: fix wrong copied

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Message-ID: <20250113160404.7ab0927d@kernel.org>
Date: Mon, 13 Jan 2025 16:04:04 -0800
From: Jakub Kicinski <kuba@...nel.org>
To: Jiayuan Chen <mrpre@....com>
Cc: bpf@...r.kernel.org, jakub@...udflare.com, john.fastabend@...il.com,
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Subject: Re: [PATCH bpf v5 1/3] bpf: fix wrong copied_seq calculation

On Thu,  9 Jan 2025 17:43:59 +0800 Jiayuan Chen wrote:
> However, for programs where both stream_parser and stream_verdict are
> active(strparser purpose), tcp_read_sock() was used instead of
> tcp_read_skb() (sk_data_ready->strp_data_ready->tcp_read_sock)
> tcp_read_sock() now still update 'sk->copied_seq', leading to duplicated
> updates.

To state the obvious feels like the abstraction between TCP and psock
has broken down pretty severely at this stage. You're modifying TCP
and straight up calling TCP functions from skmsg.c :(

> +int tcp_read_sock_noack(struct sock *sk, read_descriptor_t *desc,
> +			sk_read_actor_t recv_actor, u32 noack,
> +			u32 *copied_seq)
> +{
> +	return __tcp_read_sock(sk, desc, recv_actor,
> +			       noack, copied_seq);
> +}
> +EXPORT_SYMBOL(tcp_read_sock_noack);

Pretty sure you don't have to export this. skmsg can't be a module.