Re: [bpf PATCH v2 6/6] bpf: sockmap/tls, close can race with map free

[Jakub Kicinski <jakub.kicinski@xxxxxxxxxxxxx>]

On Mon, 08 Jul 2019 19:15:18 +0000, John Fastabend wrote:
> @@ -352,15 +354,18 @@ static void tls_sk_proto_close(struct sock *sk, long timeout)
>  	if (ctx->tx_conf == TLS_BASE && ctx->rx_conf == TLS_BASE)
>  		goto skip_tx_cleanup;
>  
> -	sk->sk_prot = ctx->sk_proto;
>  	tls_sk_proto_cleanup(sk, ctx, timeo);
>  
>  skip_tx_cleanup:
> +	write_lock_bh(&sk->sk_callback_lock);
> +	icsk->icsk_ulp_data = NULL;

Is ulp_data pointer now supposed to be updated under the
sk_callback_lock?

> +	if (sk->sk_prot->close == tls_sk_proto_close)
> +		sk->sk_prot = ctx->sk_proto;
> +	write_unlock_bh(&sk->sk_callback_lock);
>  	release_sock(sk);
>  	if (ctx->rx_conf == TLS_SW)
>  		tls_sw_release_strp_rx(ctx);
> -	sk_proto_close(sk, timeout);
> -
> +	ctx->sk_proto_close(sk, timeout);
>  	if (ctx->tx_conf != TLS_HW && ctx->rx_conf != TLS_HW &&
>  	    ctx->tx_conf != TLS_HW_RECORD && ctx->rx_conf != TLS_HW_RECORD)
>  		tls_ctx_free(ctx);