On Tue, 9 Feb 2021 12:54:59 +0100 Petr Machata wrote:
> Jian Yang <jianyang.ker...@gmail.com> writes:
>
> > From: Jian Yang <jiany...@google.com>
> >
> > Traditionally loopback devices come up with initial state as DOWN for
> > any new network-namespace. This would mean that anyone needing this
> > device would have to bring this UP by issuing something like 'ip link
> > set lo up'. This can be avoided if the initial state is set as UP.
>
> This will break user scripts, and it fact breaks kernel's very own
> selftest. We currently have this internally:
>
> diff --git a/tools/testing/selftests/net/fib_nexthops.sh
> b/tools/testing/selftests/net/fib_nexthops.sh
> index 4c7d33618437..bf8ed24ab3ba 100755
> --- a/tools/testing/selftests/net/fib_nexthops.sh
> +++ b/tools/testing/selftests/net/fib_nexthops.sh
> @@ -121,8 +121,6 @@ create_ns()
> set -e
> ip netns add ${n}
> ip netns set ${n} $((nsid++))
> - ip -netns ${n} addr add 127.0.0.1/8 dev lo
> - ip -netns ${n} link set lo up
>
> ip netns exec ${n} sysctl -qw net.ipv4.ip_forward=1
> ip netns exec ${n} sysctl -qw net.ipv4.fib_multipath_use_neigh=1
>
> This now fails because the ip commands are run within a "set -e" block,
> and kernel rejects addition of a duplicate address.
Thanks for the report, could you send a revert with this explanation?
