| From 76da0704507bbc51875013f6557877ab308cfd0a Mon Sep 17 00:00:00 2001 |
| From: WANG Cong <xiyou.wangcong@gmail.com> |
| Date: Tue, 20 Jun 2017 11:42:27 -0700 |
| Subject: ipv6: only call ip6_route_dev_notify() once for NETDEV_UNREGISTER |
| |
| From: WANG Cong <xiyou.wangcong@gmail.com> |
| |
| commit 76da0704507bbc51875013f6557877ab308cfd0a upstream. |
| |
| 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> |
| Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| net/ipv6/route.c | 6 +++++- |
| 1 file changed, 5 insertions(+), 1 deletion(-) |
| |
| --- a/net/ipv6/route.c |
| +++ b/net/ipv6/route.c |
| @@ -2827,7 +2827,11 @@ static int ip6_route_dev_notify(struct n |
| net->ipv6.ip6_blk_hole_entry->dst.dev = dev; |
| net->ipv6.ip6_blk_hole_entry->rt6i_idev = in6_dev_get(dev); |
| #endif |
| - } else if (event == NETDEV_UNREGISTER) { |
| + } else if (event == NETDEV_UNREGISTER && |
| + dev->reg_state != NETREG_UNREGISTERED) { |
| + /* NETDEV_UNREGISTER could be fired for multiple times by |
| + * netdev_wait_allrefs(). Make sure we only call this once. |
| + */ |
| in6_dev_put(net->ipv6.ip6_null_entry->rt6i_idev); |
| #ifdef CONFIG_IPV6_MULTIPLE_TABLES |
| in6_dev_put(net->ipv6.ip6_prohibit_entry->rt6i_idev); |