iproute2 ss "RTNETLINK answers: Invalid argument" with 5.4 kernel

Hi,

Since iproute2 v5.9.0, running ss on LTS kernels (for example 5.4.y)
produces error message in stderr (it's working otherwise fine, just printing
this extra error):

  $ ss
  RTNETLINK answers: Invalid argument
  ...

Bisected to:

commit 9c3be2c0eee01be7832b7900a8be798a19c659a5
Author: Paolo Abeni [off-list ref]
Date:   Fri Jul 10 15:52:35 2020 +0200

    ss: mptcp: add msk diag interface support


As 5.4 does not have any mptcp support, it's not surprising that there is
some EINVAL error. Any nice way to get rid of the error for LTS kernel
users?

-Tommi

On Thu, 2021-01-14 at 13:17 +0000, Rantala, Tommi T. (Nokia - FI/Espoo)
wrote:

Hi,

Since iproute2 v5.9.0, running ss on LTS kernels (for example 5.4.y)
produces error message in stderr (it's working otherwise fine, just printing
this extra error):

  $ ss
  RTNETLINK answers: Invalid argument
  ...

Bisected to:

commit 9c3be2c0eee01be7832b7900a8be798a19c659a5
Author: Paolo Abeni [off-list ref]
Date:   Fri Jul 10 15:52:35 2020 +0200

    ss: mptcp: add msk diag interface support


As 5.4 does not have any mptcp support, it's not surprising that there is
some EINVAL error. Any nice way to get rid of the error for LTS kernel
users?

Thank you for reporting this! I'll try to have a look ASAP -
unfortunatelly can't be before next week.

Cheers,

Paolo