From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:53444 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751239AbdEaAQ7 (ORCPT ); Tue, 30 May 2017 20:16:59 -0400 Subject: Patch "tcp: avoid fragmenting peculiar skbs in SACK" has been added to the 4.11-stable tree To: ycheng@google.com, davem@davemloft.net, edumazet@google.com, gregkh@linuxfoundation.org, ncardwell@google.com, soheil@google.com Cc: , From: Date: Wed, 31 May 2017 09:14:29 +0900 Message-ID: <149618966915830@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled tcp: avoid fragmenting peculiar skbs in SACK to the 4.11-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: tcp-avoid-fragmenting-peculiar-skbs-in-sack.patch and it can be found in the queue-4.11 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From foo@baz Wed May 31 09:13:10 JST 2017 From: Yuchung Cheng Date: Wed, 10 May 2017 17:01:27 -0700 Subject: tcp: avoid fragmenting peculiar skbs in SACK From: Yuchung Cheng [ Upstream commit b451e5d24ba6687c6f0e7319c727a709a1846c06 ] 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 Signed-off-by: Eric Dumazet Signed-off-by: Soheil Hassas Yeganeh Acked-by: Neal Cardwell Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/tcp_input.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -1174,13 +1174,14 @@ static int tcp_match_skb_to_sack(struct */ if (pkt_len > mss) { unsigned int new_len = (pkt_len / mss) * mss; - if (!in_sack && new_len < pkt_len) { + if (!in_sack && new_len < pkt_len) new_len += mss; - if (new_len >= skb->len) - return 0; - } pkt_len = new_len; } + + if (pkt_len >= skb->len && !in_sack) + return 0; + err = tcp_fragment(sk, skb, pkt_len, mss, GFP_ATOMIC); if (err < 0) return err; Patches currently in stable-queue which might be from ycheng@google.com are queue-4.11/tcp-eliminate-negative-reordering-in-tcp_clean_rtx_queue.patch queue-4.11/tcp-avoid-fragmenting-peculiar-skbs-in-sack.patch