netdev - Re: [bpf PATCH v2 2/6] bpf: tls fix transition through disconnect with close

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Message-ID: <20190710130411.08c54ddd@cakuba.netronome.com>
Date:   Wed, 10 Jul 2019 13:04:11 -0700
From:   Jakub Kicinski <jakub.kicinski@...ronome.com>
To:     John Fastabend <john.fastabend@...il.com>
Cc:     ast@...nel.org, daniel@...earbox.net, netdev@...r.kernel.org,
        edumazet@...gle.com, bpf@...r.kernel.org
Subject: Re: [bpf PATCH v2 2/6] bpf: tls fix transition through disconnect
 with close

On Wed, 10 Jul 2019 12:34:17 -0700, Jakub Kicinski wrote:
> > > > +		if (sk->sk_prot->unhash)
> > > > +			sk->sk_prot->unhash(sk);
> > > > +	}
> > > > +
> > > > +	ctx = tls_get_ctx(sk);
> > > > +	if (ctx->tx_conf == TLS_SW || ctx->rx_conf == TLS_SW)
> > > > +		tls_sk_proto_cleanup(sk, ctx, timeo);

Do we still need to hook into unhash? With patch 6 in place perhaps we
can just do disconnect 🥺

cleanup is going to kick off TX but also:

	if (unlikely(sk->sk_write_pending) &&
	    !wait_on_pending_writer(sk, &timeo))
		tls_handle_open_record(sk, 0);

Are we guaranteed that sk_write_pending is 0?  Otherwise
wait_on_pending_writer is hiding yet another release_sock() :(

> > > > +	icsk->icsk_ulp_data = NULL;    
> > > 
> > > I think close only starts checking if ctx is NULL in patch 6.
> > > Looks like some chunks of ctx checking/clearing got spread to
> > > patch 1 and some to patch 6.    
> > 
> > Yeah, I thought the patches were easier to read this way but
> > maybe not. Could add something in the commit log.  
> 
> Ack! Let me try to get a full grip of patches 2 and 6 and come back 
> to this.
> 
> > > > +	tls_ctx_free_wq(ctx);
> > > > +
> > > > +	if (ctx->unhash)
> > > > +		ctx->unhash(sk);
> > > > +}
> > > > +
> > > >  static void tls_sk_proto_close(struct sock *sk, long timeout)
> > > >  {
> > > >  	struct tls_context *ctx = tls_get_ctx(sk);