On Tue, 9 Feb 2021 18:52:04 +0100 Petr Machata wrote:
> In commit c9dca822c729 ("net-loopback: set lo dev initial state to UP"),
> linux started automatically bringing up the loopback device of a newly
> created namespace. However, an existing user script might reasonably have
> the following stanza when creating a new namespace -- and in fact at least
> tools/testing/selftests/net/fib_nexthops.sh in Linux's very own testsuite
> does:
>
> # set -e
> # ip netns add foo
> # ip -netns foo addr add 127.0.0.1/8 dev lo
> # ip -netns foo link set lo up
> # set +e
>
> This will now fail, because the kernel reasonably rejects "ip addr add" of
> a duplicate address. The described change of behavior therefore constitutes
> a breakage. Revert it.
>
> Fixes: c9dca822c729 ("net-loopback: set lo dev initial state to UP")
> Signed-off-by: Petr Machata <[email protected]>
Reviewed-by: Jakub Kicinski <[email protected]>
Thanks!
