[Devel] [PATCH rh7 v2 2/2] ms/net: use net->count to check whether a netns is alive or not

[Kirill Tkhai]

On 27.05.2020 19:11, Konstantin Khorenko wrote:
> From: Andrey Vagin <avagin at openvz.org>
> 
> The previous idea was to check whether a net namespace is in
> net_exit_list or not. It doesn't work, because net->exit_list is used in
> __register_pernet_operations and __unregister_pernet_operations where
> all namespaces are added to a temporary list to make cleanup in a error
> case, so list_empty(&net->exit_list) always returns false.
> 
> Reported-by: Mantas Mikulėnas <grawity at gmail.com>
> Fixes: 002d8a1a6c11 ("net: skip genenerating uevents for network namespaces that are exiting")
> Signed-off-by: Andrei Vagin <avagin at openvz.org>
> Signed-off-by: David S. Miller <davem at davemloft.net>
> 
> (cherry picked from commit 91864f5852f9996210fad400cf70fb85af091243)
> Signed-off-by: Konstantin Khorenko <khorenko at virtuozzo.com>

Thanks, Konstantin.

> ---
>  net/core/net-sysfs.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
> index 52199cb62bd22..18463b0a4a1e4 100644
> --- a/net/core/net-sysfs.c
> +++ b/net/core/net-sysfs.c
> @@ -920,7 +920,7 @@ net_rx_queue_update_kobjects(struct net_device *net, int old_num, int new_num)
>  	while (--i >= new_num) {
>  		struct kobject *kobj = &net->_rx[i].kobj;
>  
> -		if (!list_empty(&dev_net(net)->exit_list))
> +		if (!atomic_read(&dev_net(net)->count))
>  			kobj->uevent_suppress = 1;
>  
>  		kobject_put(kobj);
> @@ -1337,7 +1337,7 @@ netdev_queue_update_kobjects(struct net_device *net, int old_num, int new_num)
>  	while (--i >= new_num) {
>  		struct netdev_queue *queue = net->_tx + i;
>  
> -		if (!list_empty(&dev_net(net)->exit_list))
> +		if (!atomic_read(&dev_net(net)->count))
>  			queue->kobj.uevent_suppress = 1;
>  #ifdef CONFIG_BQL
>  		sysfs_remove_group(&queue->kobj, &dql_group);
> @@ -1497,7 +1497,7 @@ void netdev_unregister_kobject(struct net_device * net)
>  {
>  	struct device *dev = &(net->dev);
>  
> -	if (!list_empty(&dev_net(net)->exit_list))
> +	if (!atomic_read(&dev_net(net)->count))
>  		dev_set_uevent_suppress(dev, 1);
>  
>  	kobject_get(&dev->kobj);
>