Pavel Emelyanov wrote:
> The commits f3db4851 ([NETNS][IPV6] ip6_fib - fib6_clean_all handle several 
> network namespaces) and 69ddb805 ([NETNS][IPV6] route6 - Make proc entry 
> /proc/net/rt6_stats per namespace) made some proc files per net.
> 
> Both of them introduced potential OOPS - get_proc_net can return NULL, but
> this check is lost - and a struct net leak - in case single_open() fails the
> previously got net is not put.
> 
> Kill all these bugs with one patch.
> 
> Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
> 
> ---
> 
> diff --git a/net/ipv6/route.c b/net/ipv6/route.c
> index ac44283..cd82b6d 100644
> --- a/net/ipv6/route.c
> +++ b/net/ipv6/route.c
> @@ -2390,10 +2390,18 @@ static int ipv6_route_show(struct seq_file *m, void *v)
> 
>  static int ipv6_route_open(struct inode *inode, struct file *file)
>  {
> +	int err;
>  	struct net *net = get_proc_net(inode);
>  	if (!net)
>  		return -ENXIO;
> -	return single_open(file, ipv6_route_show, net);
> +
> +	err = single_open(file, ipv6_route_show, net);
> +	if (err < 0) {
> +		put_net(net);
> +		return err;
> +	}
> +
> +	return 0;
>  }
> 
>  static int ipv6_route_release(struct inode *inode, struct file *file)
> @@ -2429,8 +2437,18 @@ static int rt6_stats_seq_show(struct seq_file *seq, void *v)
> 
>  static int rt6_stats_seq_open(struct inode *inode, struct file *file)
>  {
> +	int err;
>  	struct net *net = get_proc_net(inode);
> -	return single_open(file, rt6_stats_seq_show, net);
> +	if (!net)
> +		return -ENXIO;
> +
> +	err = single_open(file, rt6_stats_seq_show, net);
> +	if (err < 0) {
> +		put_net(net);
> +		return err;
> +	}
> +
> +	return 0;
>  }
> 
>  static int rt6_stats_seq_release(struct inode *inode, struct file *file)

Good catch. Thanks.

Acked-by: Daniel Lezcano <dlezcano@fr.ibm.com>