* [PATCH net-next] Revert "net-loopback: set lo dev initial state to UP"
@ 2021-02-09 17:52 Petr Machata
2021-02-09 18:29 ` Jakub Kicinski
0 siblings, 1 reply; 2+ messages in thread
From: Petr Machata @ 2021-02-09 17:52 UTC (permalink / raw)
To: netdev; +Cc: Petr Machata, Jian Yang, davem, Mahesh Bandewar, Jian Yang
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(-)
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:
--
2.26.2
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH net-next] Revert "net-loopback: set lo dev initial state to UP"
2021-02-09 17:52 [PATCH net-next] Revert "net-loopback: set lo dev initial state to UP" Petr Machata
@ 2021-02-09 18:29 ` Jakub Kicinski
0 siblings, 0 replies; 2+ messages in thread
From: Jakub Kicinski @ 2021-02-09 18:29 UTC (permalink / raw)
To: Petr Machata; +Cc: netdev, Jian Yang, davem, Mahesh Bandewar, Jian Yang
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!
^ permalink raw reply [flat|nested] 2+ messages in thread
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