| Message ID | 565e72d78de80b2db767d172691bb4b682c6f4fd.1612893026.git.petrm@nvidia.com |
|---|---|
| State | New |
| Headers | show |
| Series | [net-next] Revert "net-loopback: set lo dev initial state to UP" | expand |
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 <petrm@nvidia.com> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Thanks!
diff --git a/drivers/net/loopback.c b/drivers/net/loopback.c index 24487ec17f8b..a1c77cc00416 100644 --- a/drivers/net/loopback.c +++ b/drivers/net/loopback.c @@ -219,12 +219,6 @@ static __net_init int loopback_net_init(struct net *net) BUG_ON(dev->ifindex != LOOPBACK_IFINDEX); net->loopback_dev = dev; - - /* bring loopback device UP */ - rtnl_lock(); - dev_open(dev, NULL); - rtnl_unlock(); - return 0; out_free_netdev:
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 <petrm@nvidia.com> --- drivers/net/loopback.c | 6 ------ 1 file changed, 6 deletions(-)