From: Stefano Brivio <sbri...@redhat.com>
Date: Mon, 27 May 2019 19:42:23 +0200
> In the pmtu_vti6_link_change_mtu test, both local and remote addresses
> for the vti6 tunnel are assigned to the same address given to the dummy
> interface that we use as encapsulating device with a known MTU.
>
> This works as long as the dummy interface is actually selected, via
> rt6_lookup(), as encapsulating device. But if the remote address of the
> tunnel is a local address too, the loopback interface could also be
> selected, and there's nothing wrong with it.
>
> This is what some older -stable kernels do (3.18.z, at least), and
> nothing prevents us from subtly changing FIB implementation to revert
> back to that behaviour in the future.
>
> Define an IPv6 prefix instead, and use two separate addresses as local
> and remote for vti6, so that the encapsulating device can't be a
> loopback interface.
>
> Reported-by: Xiumei Mu <x...@redhat.com>
> Fixes: 1fad59ea1c34 ("selftests: pmtu: Add pmtu_vti6_link_change_mtu test")
> Signed-off-by: Stefano Brivio <sbri...@redhat.com>
Applied.
