[Devel] [PATCH RHEL7 COMMIT] ms/ipv6: reorder ip6_route_dev_notifier after ipv6_dev_notf

[Konstantin Khorenko]

Please consider to prepare a ReadyKernel patch for this.

https://readykernel.com/

--
Best regards,

Konstantin Khorenko,
Virtuozzo Linux Kernel Team

On 07/17/2017 07:00 PM, Konstantin Khorenko wrote:
> The commit is pushed to "branch-rh7-3.10.0-514.26.1.vz7.33.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
> after rh7-3.10.0-514.26.1.vz7.33.9
> ------>
> commit e00c100739440ff23be2a3f59af233ea9f2d369b
> Author: WANG Cong <xiyou.wangcong at gmail.com>
> Date:   Mon May 8 10:12:13 2017 -0700
>
>     ms/ipv6: reorder ip6_route_dev_notifier after ipv6_dev_notf
>
>     For each netns (except init_net), we initialize its null entry
>     in 3 places:
>
>     1) The template itself, as we use kmemdup()
>     2) Code around dst_init_metrics() in ip6_route_net_init()
>     3) ip6_route_dev_notify(), which is supposed to initialize it after
>        loopback registers
>
>     Unfortunately the last one still happens in a wrong order because
>     we expect to initialize net->ipv6.ip6_null_entry->rt6i_idev to
>     net->loopback_dev's idev, thus we have to do that after we add
>     idev to loopback. However, this notifier has priority == 0 same as
>     ipv6_dev_notf, and ipv6_dev_notf is registered after
>     ip6_route_dev_notifier so it is called actually after
>     ip6_route_dev_notifier. This is similar to commit 2f460933f58e
>     ("ipv6: initialize route null entry in addrconf_init()") which
>     fixes init_net.
>
>     Fix it by picking a smaller priority for ip6_route_dev_notifier.
>     Also, we have to release the refcnt accordingly when unregistering
>     loopback_dev because device exit functions are called before subsys
>     exit functions.
>
>     Acked-by: David Ahern <dsahern at gmail.com>
>     Tested-by: David Ahern <dsahern at gmail.com>
>     Signed-off-by: Cong Wang <xiyou.wangcong at gmail.com>
>     Signed-off-by: David S. Miller <davem at davemloft.net>
>
>     https://jira.sw.ru/browse/PSBM-66197
>
>     (cherry picked from commit 242d3a49a2a1a71d8eb9f953db1bcaa9d698ce00)
>     Signed-off-by: Konstantin Khorenko <khorenko at virtuozzo.com>
> ---
>  include/net/addrconf.h |  2 ++
>  net/ipv6/addrconf.c    |  1 +
>  net/ipv6/route.c       | 13 +++++++++++--
>  3 files changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/include/net/addrconf.h b/include/net/addrconf.h
> index a17d6b9..2905c15 100644
> --- a/include/net/addrconf.h
> +++ b/include/net/addrconf.h
> @@ -19,6 +19,8 @@
>  #define ADDRCONF_TIMER_FUZZ		(HZ / 4)
>  #define ADDRCONF_TIMER_FUZZ_MAX		(HZ)
>
> +#define ADDRCONF_NOTIFY_PRIORITY	0
> +
>  #include <linux/in.h>
>  #include <linux/in6.h>
>
> diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
> index 1989b61..8d510e2 100644
> --- a/net/ipv6/addrconf.c
> +++ b/net/ipv6/addrconf.c
> @@ -3010,6 +3010,7 @@ static int addrconf_notify(struct notifier_block *this, unsigned long event,
>   */
>  static struct notifier_block ipv6_dev_notf = {
>  	.notifier_call = addrconf_notify,
> +	.priority = ADDRCONF_NOTIFY_PRIORITY,
>  };
>
>  static void addrconf_type_change(struct net_device *dev, unsigned long event)
> diff --git a/net/ipv6/route.c b/net/ipv6/route.c
> index 99957f7..3d4d519 100644
> --- a/net/ipv6/route.c
> +++ b/net/ipv6/route.c
> @@ -3216,7 +3216,10 @@ static int ip6_route_dev_notify(struct notifier_block *this,
>  	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
>  	struct net *net = dev_net(dev);
>
> -	if (event == NETDEV_REGISTER && (dev->flags & IFF_LOOPBACK)) {
> +	if (!(dev->flags & IFF_LOOPBACK))
> +		return NOTIFY_OK;
> +
> +	if (event == NETDEV_REGISTER) {
>  		net->ipv6.ip6_null_entry->dst.dev = dev;
>  		net->ipv6.ip6_null_entry->rt6i_idev = in6_dev_get(dev);
>  #ifdef CONFIG_IPV6_MULTIPLE_TABLES
> @@ -3225,6 +3228,12 @@ static int ip6_route_dev_notify(struct notifier_block *this,
>  		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) {
> +		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);
> +		in6_dev_put(net->ipv6.ip6_blk_hole_entry->rt6i_idev);
> +#endif
>  	}
>
>  	return NOTIFY_OK;
> @@ -3531,7 +3540,7 @@ static struct pernet_operations ip6_route_net_late_ops = {
>
>  static struct notifier_block ip6_route_dev_notifier = {
>  	.notifier_call = ip6_route_dev_notify,
> -	.priority = 0,
> +	.priority = ADDRCONF_NOTIFY_PRIORITY - 10,
>  };
>
>  #if 0
> .
>