From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.toke.dk (mail.toke.dk [52.28.52.200]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 3A3E23CB35 for ; Thu, 13 Sep 2018 10:44:52 -0400 (EDT) From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=toke.dk; s=20161023; t=1536849891; bh=lCCzoQD7i2erxUtPk9xxcIKTjFPHWkaxKEL2p1LiDAI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZuKMMBeRI1sHfS3GlOZJ1+ArArdblYTtisxN+/4u+JehYwkCxBOcJbX9EEeVxABzp 0CyEuX6KXliDp6S/K6i6VW3CMlvaa9i4Oy7a2ugeLcf4YXB3D/tlvJlW+QL6hqEqGa ow11+4haoAUCopnPcfMNkW2T4B1qkiQIGtKmoIW/hgZA3ziLMmYtB8yDTutb3EIhGl QSNTZsphme1kWSzTyXDk7pwGmm4pnqMWQOmn/LaL55QQVM6RtimHXeR/3ZXRGfZY2A fXlsVq0bpPH9uCkCWN/Y6kUC0NqlQ/urilZBlQbKRBzQ7iNMnW0dNsTIQIXbQKQNa9 6teLRbol/on0Q== To: netdev@vger.kernel.org Cc: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= , cake@lists.bufferbloat.net, David Miller , Eric Dumazet , Dave Taht Date: Thu, 13 Sep 2018 16:43:07 +0200 Message-Id: <20180913144306.9077-1-toke@toke.dk> In-Reply-To: <153670437243.12756.693381878569982309.stgit@alrua-kau> References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Subject: [Cake] [PATCH net v2] gso_segment: Reset skb->mac_len after modifying network header X-BeenThere: cake@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Cake - FQ_codel the next generation List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 13 Sep 2018 14:44:52 -0000 When splitting a GSO segment that consists of encapsulated packets, the skb->mac_len of the segments can end up being set wrong, causing packet drops in particular when using act_mirred and ifb interfaces in combination with a qdisc that splits GSO packets. This happens because at the time skb_segment() is called, network_header will point to the inner header, throwing off the calculation in skb_reset_mac_len(). The network_header is subsequently adjust by the outer IP gso_segment handlers, but they don't set the mac_len. Fix this by adding skb_reset_mac_len() calls to both the IPv4 and IPv6 gso_segment handlers, after they modify the network_header. Many thanks to Eric Dumazet for his help in identifying the cause of the bug. Acked-by: Dave Taht Reviewed-by: Eric Dumazet Signed-off-by: Toke Høiland-Jørgensen --- v2: - Properly credit Eric for his help - Add review and ack tags net/ipv4/af_inet.c | 1 + net/ipv6/ip6_offload.c | 1 + 2 files changed, 2 insertions(+) diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index 20fda8fb8ffd..1fbe2f815474 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -1377,6 +1377,7 @@ struct sk_buff *inet_gso_segment(struct sk_buff *skb, if (encap) skb_reset_inner_headers(skb); skb->network_header = (u8 *)iph - skb->head; + skb_reset_mac_len(skb); } while ((skb = skb->next)); out: diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c index 37ff4805b20c..c7e495f12011 100644 --- a/net/ipv6/ip6_offload.c +++ b/net/ipv6/ip6_offload.c @@ -115,6 +115,7 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb, payload_len = skb->len - nhoff - sizeof(*ipv6h); ipv6h->payload_len = htons(payload_len); skb->network_header = (u8 *)ipv6h - skb->head; + skb_reset_mac_len(skb); if (udpfrag) { int err = ip6_find_1stfragopt(skb, &prevhdr); -- 2.18.0