netdev - Re: [PATCH net-next v5 10/11] tcp: clean ext on tx recycle

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Date:   Fri, 20 Dec 2019 07:29:05 -0800
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     Mat Martineau <mathew.j.martineau@...ux.intel.com>,
        netdev@...r.kernel.org, mptcp@...ts.01.org
Cc:     Paolo Abeni <pabeni@...hat.com>, Florian Westphal <fw@...len.de>
Subject: Re: [PATCH net-next v5 10/11] tcp: clean ext on tx recycle



On 12/19/19 2:34 PM, Mat Martineau wrote:
> From: Paolo Abeni <pabeni@...hat.com>
> 
> Otherwise we will find stray/unexpected/old extensions value on next
> iteration.
> 
> On tcp_write_xmit() we can end-up splitting an already queued skb in two
> parts, via tso_fragment(). The newly created skb can be allocated via
> the tx cache and an upper layer will not be aware of it, so that upper
> layer cannot set the ext properly.
> 
> Resetting the ext on recycle ensures that stale data is not propagated
> in to packet headers or elsewhere.
> 
> An alternative would be add an additional hook in tso_fragment() or in
> sk_stream_alloc_skb() to init the ext for upper layers that need it.
> 
> Co-developed-by: Florian Westphal <fw@...len.de>
> Signed-off-by: Florian Westphal <fw@...len.de>
> Signed-off-by: Paolo Abeni <pabeni@...hat.com>
> Signed-off-by: Mat Martineau <mathew.j.martineau@...ux.intel.com>
> ---

Reviewed-by: Eric Dumazet <edumazet@...gle.com>