Re: [Patch net] 8021q: fix a memory leak for VLAN 0 device

[Nikolay Aleksandrov <nikolay@cumulusnetworks.com>]

On 09/01/18 23:40, Cong Wang wrote:
> A vlan device with vid 0 is allow to creat by not able to be fully
> cleaned up by unregister_vlan_dev() which checks for vlan_id!=0.
> 
> Also, VLAN 0 is probably not a valid number and it is kinda
> "reserved" for HW accelerating devices, but it is probably too
> late to reject it from creation even if makes sense. Instead,
> just remove the check in unregister_vlan_dev().
> 
> Reported-by: Dmitry Vyukov <dvyukov@google.com>
> Fixes: ad1afb003939 ("vlan_dev: VLAN 0 should be treated as "no vlan tag" (802.1p packet)")
> Cc: Vlad Yasevich <vyasevich@gmail.com>
> Cc: Ben Hutchings <ben.hutchings@codethink.co.uk>
> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
> ---
>  net/8021q/vlan.c | 7 +------
>  1 file changed, 1 insertion(+), 6 deletions(-)
> 
> diff --git a/net/8021q/vlan.c b/net/8021q/vlan.c
> index 8dfdd94e430f..bad01b14a4ad 100644
> --- a/net/8021q/vlan.c
> +++ b/net/8021q/vlan.c
> @@ -111,12 +111,7 @@ void unregister_vlan_dev(struct net_device *dev, struct list_head *head)
>  		vlan_gvrp_uninit_applicant(real_dev);
>  	}
>  
> -	/* Take it out of our own structures, but be sure to interlock with
> -	 * HW accelerating devices or SW vlan input packet processing if
> -	 * VLAN is not 0 (leave it there for 802.1p).
> -	 */
> -	if (vlan_id)
> -		vlan_vid_del(real_dev, vlan->vlan_proto, vlan_id);
> +	vlan_vid_del(real_dev, vlan->vlan_proto, vlan_id);
>  
>  	/* Get rid of the vlan's reference to real_dev */
>  	dev_put(real_dev);
> 

Just for reference - this is identical to the first part of:
https://patchwork.ozlabs.org/patch/252891/

I knew this looked familiar. :-)