From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Borkmann Subject: [PATCH net] net: sctp: use MAX_HEADER for headroom reserve in output path Date: Wed, 3 Dec 2014 12:13:58 +0100 Message-ID: <1417605238-9936-1-git-send-email-dborkman@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: linux-sctp@vger.kernel.org, netdev@vger.kernel.org, robert@swiecki.net To: davem@davemloft.net Return-path: Received: from mx1.redhat.com ([209.132.183.28]:46662 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751982AbaLCLOE (ORCPT ); Wed, 3 Dec 2014 06:14:04 -0500 Sender: netdev-owner@vger.kernel.org List-ID: To accomodate for enough headroom for tunnels, use MAX_HEADER instead of LL_MAX_HEADER. Robert reported that he has hit after roughly 40hrs of trinity an skb_under_panic() via SCTP output path (see reference). I couldn't reproduce it from here, but not using MAX_HEADER as elsewher= e in other protocols might be one possible cause for this. In any case, it looks like accounting on chunks themself seems to look good as the skb already passed the SCTP output path and did not hit any skb_over_panic(). Given tunneling was enabled in his .config, the headroom would have been expanded by MAX_HEADER in this case. Reported-by: Robert =C5=9Awi=C4=99cki Reference: https://lkml.org/lkml/2014/12/1/507 =46ixes: 594ccc14dfe4d ("[SCTP] Replace incorrect use of dev_alloc_skb = with alloc_skb in sctp_packet_transmit().") Signed-off-by: Daniel Borkmann --- net/sctp/output.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/sctp/output.c b/net/sctp/output.c index 42dffd4..fc5e45b 100644 --- a/net/sctp/output.c +++ b/net/sctp/output.c @@ -401,12 +401,12 @@ int sctp_packet_transmit(struct sctp_packet *pack= et) sk =3D chunk->skb->sk; =20 /* Allocate the new skb. */ - nskb =3D alloc_skb(packet->size + LL_MAX_HEADER, GFP_ATOMIC); + nskb =3D alloc_skb(packet->size + MAX_HEADER, GFP_ATOMIC); if (!nskb) goto nomem; =20 /* Make sure the outbound skb has enough header room reserved. */ - skb_reserve(nskb, packet->overhead + LL_MAX_HEADER); + skb_reserve(nskb, packet->overhead + MAX_HEADER); =20 /* Set the owning socket so that we know where to get the * destination IP address. --=20 1.7.11.7