From: David Miller <davem@davemloft.net>
To: ycheng@google.com
Cc: netdev@vger.kernel.org, ncardwell@google.com,
edumazet@google.com, soheil@google.com
Subject: Re: [PATCH net] tcp: avoid fragmenting peculiar skbs in SACK
Date: Thu, 11 May 2017 21:36:09 -0400 (EDT) [thread overview]
Message-ID: <20170511.213609.1826897036363570671.davem@davemloft.net> (raw)
In-Reply-To: <20170511000127.4249-1-ycheng@google.com>
From: Yuchung Cheng <ycheng@google.com>
Date: Wed, 10 May 2017 17:01:27 -0700
> This patch fixes a bug in splitting an SKB during SACK
> processing. Specifically if an skb contains multiple
> packets and is only partially sacked in the higher sequences,
> tcp_match_sack_to_skb() splits the skb and marks the second fragment
> as SACKed.
>
> The current code further attempts rounding up the first fragment
> to MSS boundaries. But it misses a boundary condition when the
> rounded-up fragment size (pkt_len) is exactly skb size. Spliting
> such an skb is pointless and causses a kernel warning and aborts
> the SACK processing. This patch universally checks such over-split
> before calling tcp_fragment to prevent these unnecessary warnings.
>
> Fixes: adb92db857ee ("tcp: Make SACK code to split only at mss boundaries")
> Signed-off-by: Yuchung Cheng <ycheng@google.com>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
Hehe, a 2.6.29 bug, funny that it lived for so long.
Applied and queued up for -stable, thanks!
prev parent reply other threads:[~2017-05-12 1:36 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-11 0:01 [PATCH net] tcp: avoid fragmenting peculiar skbs in SACK Yuchung Cheng
2017-05-11 1:33 ` Neal Cardwell
2017-05-12 1:36 ` David Miller [this message]
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