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Revert "net-loopback: set lo dev initial state to UP"

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In commit c9dca822c7 ("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: c9dca822c7 ("net-loopback: set lo dev initial state to UP")
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Petr Machata 2021-02-09 18:52:04 +01:00 committed by David S. Miller
parent 4217a64e18
commit 1edb5cbf49
1 changed files with 0 additions and 6 deletions
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6
drivers/net/loopback.c
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@ -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: