ipv6: only call ip6_route_dev_notify() once for NETDEV_UNREGISTER
authorWANG Cong <xiyou.wangcong@gmail.com>
Tue, 20 Jun 2017 18:42:27 +0000 (11:42 -0700)
committerDavid S. Miller <davem@davemloft.net>
Thu, 22 Jun 2017 15:06:06 +0000 (11:06 -0400)
commit76da0704507bbc51875013f6557877ab308cfd0a
treebcfd0d5bb6df4ad832b37676ca2c8ec229473de5
parentb866203d872d5deeafcecd25ea429d6748b5bd56
ipv6: only call ip6_route_dev_notify() once for NETDEV_UNREGISTER

In commit 242d3a49a2a1 ("ipv6: reorder ip6_route_dev_notifier after ipv6_dev_notf")
I assumed NETDEV_REGISTER and NETDEV_UNREGISTER are paired,
unfortunately, as reported by jeffy, netdev_wait_allrefs()
could rebroadcast NETDEV_UNREGISTER event until all refs are
gone.

We have to add an additional check to avoid this corner case.
For netdev_wait_allrefs() dev->reg_state is NETREG_UNREGISTERED,
for dev_change_net_namespace(), dev->reg_state is
NETREG_REGISTERED. So check for dev->reg_state != NETREG_UNREGISTERED.

Fixes: 242d3a49a2a1 ("ipv6: reorder ip6_route_dev_notifier after ipv6_dev_notf")
Reported-by: jeffy <jeffy.chen@rock-chips.com>
Cc: David Ahern <dsahern@gmail.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/ipv6/route.c