This is a note to let you know that I've just added the patch titled

sched: act_csum: don't mangle TCP and UDP GSO packets

to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: sched-act_csum-don-t-mangle-tcp-and-udp-gso-packets.patch and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From foo@baz Sun Mar 18 16:55:33 CET 2018

From: Davide Caratti dcaratti@redhat.com Date: Thu, 23 Mar 2017 10:39:40 +0100 Subject: sched: act_csum: don't mangle TCP and UDP GSO packets

From: Davide Caratti dcaratti@redhat.com

[ 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@redhat.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/sched/act_csum.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)

--- a/net/sched/act_csum.c +++ b/net/sched/act_csum.c @@ -180,6 +180,9 @@ 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; @@ -201,6 +204,9 @@ 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; @@ -224,6 +230,9 @@ 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, @@ -277,6 +286,9 @@ 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,

Patches currently in stable-queue which might be from dcaratti@redhat.com are

queue-4.9/sched-act_csum-don-t-mangle-tcp-and-udp-gso-packets.patch