netdev - Re: [PATCH bpf-next 1/4] bpf, sockmap: Fix memleak in sk_psock_queue

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Message-ID: <621d96888e266_8c479208da@john.notmuch>
Date:   Mon, 28 Feb 2022 19:44:08 -0800
From:   John Fastabend <john.fastabend@...il.com>
To:     wangyufen <wangyufen@...wei.com>,
        Cong Wang <xiyou.wangcong@...il.com>
Cc:     john.fastabend@...il.com, daniel@...earbox.net,
        jakub@...udflare.com, lmb@...udflare.com, davem@...emloft.net,
        bpf@...r.kernel.org, edumazet@...gle.com, yoshfuji@...ux-ipv6.org,
        dsahern@...nel.org, kuba@...nel.org, ast@...nel.org,
        andrii@...nel.org, kafai@...com, songliubraving@...com, yhs@...com,
        kpsingh@...nel.org, netdev@...r.kernel.org
Subject: Re: [PATCH bpf-next 1/4] bpf, sockmap: Fix memleak in
 sk_psock_queue_msg

wangyufen wrote:
> 
> 在 2022/2/28 3:21, Cong Wang 写道:
> > On Fri, Feb 25, 2022 at 09:49:26AM +0800, Wang Yufen wrote:
> >> If tcp_bpf_sendmsg is running during a tear down operation we may enqueue
> >> data on the ingress msg queue while tear down is trying to free it.
> >>
> >>   sk1 (redirect sk2)                         sk2
> >>   -------------------                      ---------------
> >> tcp_bpf_sendmsg()
> >>   tcp_bpf_send_verdict()
> >>    tcp_bpf_sendmsg_redir()
> >>     bpf_tcp_ingress()
> >>                                            sock_map_close()
> >>                                             lock_sock()
> >>      lock_sock() ... blocking
> >>                                             sk_psock_stop
> >>                                              sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED);
> >>                                             release_sock(sk);
> >>      lock_sock()	
> >>      sk_mem_charge()
> >>      get_page()
> >>      sk_psock_queue_msg()
> >>       sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED);
> >>        drop_sk_msg()
> >>      release_sock()
> >>
> >> While drop_sk_msg(), the msg has charged memory form sk by sk_mem_charge
> >> and has sg pages need to put. To fix we use sk_msg_free() and then kfee()
> >> msg.
> >>
> > What about the other code path? That is, sk_psock_skb_ingress_enqueue().
> > I don't see skmsg is charged there.
> 
> sk_psock_skb_ingress_self() | sk_psock_skb_ingress()
>     skb_set_owner_r()
>        sk_mem_charge()
>     sk_psock_skb_ingress_enqueue()
> 
> The other code path skmsg is charged by skb_set_owner_r()->sk_mem_charge()
> 
> >
> > Thanks.
> > .

I walked that code and fix LGTM as well.

Acked-by: John Fastabend <john.fastabend@...il.com>