sched: act_csum: don't mangle TCP and UDP GSO packets
authorDavide Caratti <dcaratti@redhat.com>
Thu, 23 Mar 2017 09:39:40 +0000 (10:39 +0100)
committerDavid S. Miller <davem@davemloft.net>
Fri, 24 Mar 2017 00:40:33 +0000 (17:40 -0700)
commitadd641e7dee31b36aee83412c29e39dd1f5e0c9c
tree3e571e30111d4b8898885e0772fbc5d98595542e
parent67ff2c71bbf21fae0f63b367f252653c4abc3b12
sched: act_csum: don't mangle TCP and UDP GSO packets

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>
net/sched/act_csum.c