netdev - [PATCH bpf v2 1/3] bpf, sockmap: zap ingress queues after stopping strparser

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Date:   Mon, 26 Jul 2021 09:53:02 -0700
From:   John Fastabend <john.fastabend@...il.com>
To:     jakub@...udflare.com, daniel@...earbox.net,
        xiyou.wangcong@...il.com, alexei.starovoitov@...il.com
Cc:     bpf@...r.kernel.org, netdev@...r.kernel.org,
        john.fastabend@...il.com
Subject: [PATCH bpf v2 1/3] bpf, sockmap: zap ingress queues after stopping strparser

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")
Acked-by: Jakub Sitnicki <jakub@...udflare.com>
Signed-off-by: John Fastabend <john.fastabend@...il.com>
---
 net/core/skmsg.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/core/skmsg.c b/net/core/skmsg.c
index 15d71288e741..28115ef742e8 100644
--- a/net/core/skmsg.c
+++ b/net/core/skmsg.c
@@ -773,8 +773,6 @@ static void sk_psock_destroy(struct work_struct *work)
 
 void sk_psock_drop(struct sock *sk, struct sk_psock *psock)
 {
-	sk_psock_stop(psock, false);
-
 	write_lock_bh(&sk->sk_callback_lock);
 	sk_psock_restore_proto(sk, psock);
 	rcu_assign_sk_user_data(sk, NULL);
@@ -784,6 +782,8 @@ void sk_psock_drop(struct sock *sk, struct sk_psock *psock)
 		sk_psock_stop_verdict(sk, psock);
 	write_unlock_bh(&sk->sk_callback_lock);
 
+	sk_psock_stop(psock, false);
+
 	INIT_RCU_WORK(&psock->rwork, sk_psock_destroy);
 	queue_rcu_work(system_wq, &psock->rwork);
 }
-- 
2.25.1