3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Davide Caratti <dcaratti@xxxxxxxxxx> [ Upstream commit add641e7dee31b36aee83412c29e39dd1f5e0c9c ] after act_csum computes the checksum on skbs carrying GSO TCP/UDP packets, subsequent segmentation fails because skb_needs_check(skb, true) returns true. Because of that, skb_warn_bad_offload() is invoked and the following message is displayed: WARNING: CPU: 3 PID: 28 at net/core/dev.c:2553 skb_warn_bad_offload+0xf0/0xfd <...> [<ffffffff8171f486>] skb_warn_bad_offload+0xf0/0xfd [<ffffffff8161304c>] __skb_gso_segment+0xec/0x110 [<ffffffff8161340d>] validate_xmit_skb+0x12d/0x2b0 [<ffffffff816135d2>] validate_xmit_skb_list+0x42/0x70 [<ffffffff8163c560>] sch_direct_xmit+0xd0/0x1b0 [<ffffffff8163c760>] __qdisc_run+0x120/0x270 [<ffffffff81613b3d>] __dev_queue_xmit+0x23d/0x690 [<ffffffff81613fa0>] dev_queue_xmit+0x10/0x20 Since GSO is able to compute checksum on individual segments of such skbs, we can simply skip mangling the packet. Signed-off-by: Davide Caratti <dcaratti@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/sched/act_csum.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) --- a/net/sched/act_csum.c +++ b/net/sched/act_csum.c @@ -176,6 +176,9 @@ static int tcf_csum_ipv4_tcp(struct sk_b struct tcphdr *tcph; const struct iphdr *iph; + if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4) + return 1; + tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph)); if (tcph == NULL) return 0; @@ -197,6 +200,9 @@ static int tcf_csum_ipv6_tcp(struct sk_b struct tcphdr *tcph; const struct ipv6hdr *ip6h; + if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) + return 1; + tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph)); if (tcph == NULL) return 0; @@ -220,6 +226,9 @@ static int tcf_csum_ipv4_udp(struct sk_b const struct iphdr *iph; u16 ul; + if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_UDP) + return 1; + /* * Support both UDP and UDPLITE checksum algorithms, Don't use * udph->len to get the real length without any protocol check, @@ -273,6 +282,9 @@ static int tcf_csum_ipv6_udp(struct sk_b const struct ipv6hdr *ip6h; u16 ul; + if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_UDP) + return 1; + /* * Support both UDP and UDPLITE checksum algorithms, Don't use * udph->len to get the real length without any protocol check,