3.18-stable review patch. If anyone has any objections, please let me know.
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From: Toke Høiland-Jørgensen toke@toke.dk
[ Upstream commit c56cae23c6b167acc68043c683c4573b80cbcc2c ]
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 dave.taht@gmail.com Reviewed-by: Eric Dumazet edumazet@google.com Signed-off-by: Toke Høiland-Jørgensen toke@toke.dk Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv4/af_inet.c | 1 + net/ipv6/ip6_offload.c | 1 + 2 files changed, 2 insertions(+)
--- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -1288,6 +1288,7 @@ static struct sk_buff *inet_gso_segment( if (encap) skb_reset_inner_headers(skb); skb->network_header = (u8 *)iph - skb->head; + skb_reset_mac_len(skb); } while ((skb = skb->next));
out: --- a/net/ipv6/ip6_offload.c +++ b/net/ipv6/ip6_offload.c @@ -118,6 +118,7 @@ static struct sk_buff *ipv6_gso_segment( ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff); ipv6h->payload_len = htons(skb->len - nhoff - sizeof(*ipv6h)); skb->network_header = (u8 *)ipv6h - skb->head; + skb_reset_mac_len(skb);
if (udpfrag) { int err = ip6_find_1stfragopt(skb, &prevhdr);