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From: Jakub Sitnicki <jakub@cloudflare.com>
To: John Fastabend <john.fastabend@gmail.com>
Cc: daniel@iogearbox.net, xiyou.wangcong@gmail.com,
	alexei.starovoitov@gmail.com, bpf@vger.kernel.org,
	netdev@vger.kernel.org
Subject: Re: [PATCH bpf 1/3] bpf, sockmap: zap ingress queues after stopping strparser
Date: Tue, 20 Jul 2021 12:27:22 +0200	[thread overview]
Message-ID: <87v955qnzp.fsf@cloudflare.com> (raw)
In-Reply-To: <20210719214834.125484-2-john.fastabend@gmail.com>

On Mon, Jul 19, 2021 at 11:48 PM CEST, John Fastabend wrote:
> We don't want strparser to run and pass skbs into skmsg handlers when
> the psock is null. We just sk_drop them in this case. When removing
> a live socket from map it means extra drops that we do not need to
> incur. Move the zap below strparser close to avoid this condition.
>
> This way we stop the stream parser first stopping it from processing
> packets and then delete the psock.
>
> Fixes: a136678c0bdbb ("bpf: sk_msg, zap ingress queue on psock down")
> Signed-off-by: John Fastabend <john.fastabend@gmail.com>
> ---

To confirm my understanding - the extra drops can happen because
currently we are racing to clear SK_PSOCK_TX_ENABLED flag in
sk_psock_drop with sk_psock_verdict_apply, which checks the flag before
pushing skb onto psock->ingress_skb queue (or possibly straight into
psock->ingress_msg queue on no redirect).

  reply	other threads:[~2021-07-20 10:28 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-19 21:48 [PATCH bpf 0/3] sockmap fixes picked up by stress tests John Fastabend
2021-07-19 21:48 ` [PATCH bpf 1/3] bpf, sockmap: zap ingress queues after stopping strparser John Fastabend
2021-07-20 10:27   ` Jakub Sitnicki [this message]
2021-07-20 17:41     ` John Fastabend
2021-07-19 21:48 ` [PATCH bpf 2/3] bpf, sockmap: on cleanup we additionally need to remove cached skb John Fastabend
2021-07-21  9:38   ` Dan Carpenter
2021-07-21 10:13   ` Jakub Sitnicki
2021-07-19 21:48 ` [PATCH bpf 3/3] bpf, sockmap: fix memleak on ingress msg enqueue John Fastabend
2021-07-21 16:36   ` Jakub Sitnicki
2021-07-21 18:02   ` Martin KaFai Lau
2021-07-21 16:38 ` [PATCH bpf 0/3] sockmap fixes picked up by stress tests Jakub Sitnicki

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