Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754065AbaG3Mf2 (ORCPT ); Wed, 30 Jul 2014 08:35:28 -0400 Received: from ip4-83-240-18-248.cust.nbox.cz ([83.240.18.248]:36713 "EHLO ip4-83-240-18-248.cust.nbox.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752872AbaG3MPc (ORCPT ); Wed, 30 Jul 2014 08:15:32 -0400 From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Wei-Chun Chao , "David S. Miller" , Jiri Slaby Subject: [PATCH 3.12 37/94] net: fix UDP tunnel GSO of frag_list GRO packets Date: Wed, 30 Jul 2014 14:14:26 +0200 Message-Id: <1ea464333aa10210b8b285a8a64ce17211569156.1406722270.git.jslaby@suse.cz> X-Mailer: git-send-email 2.0.1 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Wei-Chun Chao 3.12-stable review patch. If anyone has any objections, please let me know. =============== [ Upstream commit 5882a07c72093dc3a18e2d2b129fb200686bb6ee ] This patch fixes a kernel BUG_ON in skb_segment. It is hit when testing two VMs on openvswitch with one VM acting as VXLAN gateway. During VXLAN packet GSO, skb_segment is called with skb->data pointing to inner TCP payload. skb_segment calls skb_network_protocol to retrieve the inner protocol. skb_network_protocol actually expects skb->data to point to MAC and it calls pskb_may_pull with ETH_HLEN. This ends up pulling in ETH_HLEN data from header tail. As a result, pskb_trim logic is skipped and BUG_ON is hit later. Move skb_push in front of skb_network_protocol so that skb->data lines up properly. kernel BUG at net/core/skbuff.c:2999! Call Trace: [] tcp_gso_segment+0x122/0x410 [] inet_gso_segment+0x13c/0x390 [] skb_mac_gso_segment+0x9b/0x170 [] skb_udp_tunnel_segment+0xd8/0x390 [] udp4_ufo_fragment+0x120/0x140 [] inet_gso_segment+0x13c/0x390 [] ? default_wake_function+0x12/0x20 [] skb_mac_gso_segment+0x9b/0x170 [] __skb_gso_segment+0x60/0xc0 [] dev_hard_start_xmit+0x183/0x550 [] sch_direct_xmit+0xfe/0x1d0 [] __dev_queue_xmit+0x214/0x4f0 [] dev_queue_xmit+0x10/0x20 [] ip_finish_output+0x66b/0x890 [] ip_output+0x58/0x90 [] ? fib_table_lookup+0x29f/0x350 [] ip_local_out_sk+0x39/0x50 [] iptunnel_xmit+0x10d/0x130 [] vxlan_xmit_skb+0x1d0/0x330 [vxlan] [] vxlan_tnl_send+0x129/0x1a0 [openvswitch] [] ovs_vport_send+0x26/0xa0 [openvswitch] [] do_output+0x2e/0x50 [openvswitch] Signed-off-by: Wei-Chun Chao Signed-off-by: David S. Miller Signed-off-by: Jiri Slaby --- net/core/skbuff.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 5a60953e6f39..aeb870c5c134 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -2744,12 +2744,13 @@ struct sk_buff *skb_segment(struct sk_buff *head_skb, int i = 0; int pos; + __skb_push(head_skb, doffset); proto = skb_network_protocol(head_skb); if (unlikely(!proto)) return ERR_PTR(-EINVAL); csum = !!can_checksum_protocol(features, proto); - __skb_push(head_skb, doffset); + headroom = skb_headroom(head_skb); pos = skb_headlen(head_skb); -- 2.0.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/