RE: [PATCH bpf] bpf, sockmap: Fix bug that strp_done cannot be called

[John Fastabend <john.fastabend@gmail.com>]

Xu Kuohai wrote:
> From: Xu Kuohai <xukuohai@huawei.com>
> 
> strp_done is only called when psock->progs.stream_parser is not NULL,
> but stream_parser was set to NULL by sk_psock_stop_strp(), called
> by sk_psock_drop() earlier. So, strp_done can never be called.
> 
> Introduce SK_PSOCK_RX_ENABLED to mark whether there is strp on psock.
> Change the condition for calling strp_done from judging whether
> stream_parser is set to judging whether this flag is set. This flag is
> only set once when strp_init() succeeds, and will never be cleared later.
> 
> Fixes: c0d95d3380ee ("bpf, sockmap: Re-evaluate proto ops when psock is removed from sockmap")
> Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
> ---
>  include/linux/skmsg.h |  1 +
>  net/core/skmsg.c      | 10 ++++++++--
>  2 files changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h
> index 054d7911bfc9..959c5f4c4d19 100644
> --- a/include/linux/skmsg.h
> +++ b/include/linux/skmsg.h
> @@ -62,6 +62,7 @@ struct sk_psock_progs {
>  
>  enum sk_psock_state_bits {
>  	SK_PSOCK_TX_ENABLED,
> +	SK_PSOCK_RX_ENABLED,

small nit can be make this SK_PSOCK_RX_STRP_ENABLED? That way its
explicit what we are talking about here.

Otherwise it looks good thanks nice catch.

>  };
>  
>  struct sk_psock_link {
> diff --git a/net/core/skmsg.c b/net/core/skmsg.c
> index a29508e1ff35..7c2764beeb04 100644
> --- a/net/core/skmsg.c
> +++ b/net/core/skmsg.c
> @@ -1120,13 +1120,19 @@ static void sk_psock_strp_data_ready(struct sock *sk)
>  
>  int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock)
>  {
> +	int ret;
> +
>  	static const struct strp_callbacks cb = {
>  		.rcv_msg	= sk_psock_strp_read,
>  		.read_sock_done	= sk_psock_strp_read_done,
>  		.parse_msg	= sk_psock_strp_parse,
>  	};
>  
> -	return strp_init(&psock->strp, sk, &cb);
> +	ret = strp_init(&psock->strp, sk, &cb);
> +	if (!ret)
> +		sk_psock_set_state(psock, SK_PSOCK_RX_ENABLED);
> +
> +	return ret;
>  }
>  
>  void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock)
> @@ -1154,7 +1160,7 @@ void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock)
>  static void sk_psock_done_strp(struct sk_psock *psock)
>  {
>  	/* Parser has been stopped */
> -	if (psock->progs.stream_parser)
> +	if (sk_psock_test_state(psock, SK_PSOCK_RX_ENABLED))
>  		strp_done(&psock->strp);
>  }
>  #else
> -- 
> 2.30.2
>