From: David Miller <davem@davemloft.net>
To: eric.dumazet@gmail.com
Cc: cpaasch@apple.com, edumazet@google.com, netdev@vger.kernel.org
Subject: Re: [PATCH net] tcp: do not mangle skb->cb[] in tcp_make_synack()
Date: Fri, 03 Nov 2017 14:32:14 +0900 (KST) [thread overview]
Message-ID: <20171103.143214.32665592248209118.davem@davemloft.net> (raw)
In-Reply-To: <1509651025.2849.23.camel@edumazet-glaptop3.roam.corp.google.com>
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Thu, 02 Nov 2017 12:30:25 -0700
> From: Eric Dumazet <edumazet@google.com>
>
> Christoph Paasch sent a patch to address the following issue :
>
> tcp_make_synack() is leaving some TCP private info in skb->cb[],
> then send the packet by other means than tcp_transmit_skb()
>
> tcp_transmit_skb() makes sure to clear skb->cb[] to not confuse
> IPv4/IPV6 stacks, but we have no such cleanup for SYNACK.
>
> tcp_make_synack() should not use tcp_init_nondata_skb() :
>
> tcp_init_nondata_skb() really should be limited to skbs put in write/rtx
> queues (the ones that are only sent via tcp_transmit_skb())
>
> This patch fixes the issue and should even save few cpu cycles ;)
>
> Fixes: 971f10eca186 ("tcp: better TCP_SKB_CB layout to reduce cache line misses")
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Reported-by: Christoph Paasch <cpaasch@apple.com>
Applied and queued up for -stable.
next prev parent reply other threads:[~2017-11-03 5:32 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-01 21:10 [PATCH net] tcp: Always cleanup skb before sending Christoph Paasch
2017-11-01 21:32 ` Eric Dumazet
2017-11-01 21:53 ` Eric Dumazet
2017-11-02 0:10 ` Christoph Paasch
2017-11-02 1:00 ` Eric Dumazet
2017-11-02 2:21 ` Eric Dumazet
2017-11-02 18:24 ` Christoph Paasch
2017-11-02 18:26 ` Eric Dumazet
2017-11-02 18:31 ` Christoph Paasch
2017-11-02 19:30 ` [PATCH net] tcp: do not mangle skb->cb[] in tcp_make_synack() Eric Dumazet
2017-11-02 19:49 ` Christoph Paasch
2017-11-03 5:32 ` David Miller [this message]
2017-11-02 18:16 ` [PATCH net] tcp: Always cleanup skb before sending Christoph Paasch
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