On Tue, Feb 9, 2021 at 8:23 AM Jakub Kicinski <k...@kernel.org> wrote:
>
> 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?
Rather than revert, shouldn't we just fix the self-test in that regard?
