netdev - Re: [PATCH net] net: vlan: sync VLAN features with lower device

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <38605efc-32f5-4c78-a628-11f8f07668f0@redhat.com>
Date: Thu, 23 Oct 2025 15:39:07 +0200
From: Paolo Abeni <pabeni@...hat.com>
To: Hangbin Liu <liuhangbin@...il.com>, netdev@...r.kernel.org
Cc: "David S. Miller" <davem@...emloft.net>,
 Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>,
 Simon Horman <horms@...nel.org>, Stanislav Fomichev <sdf@...ichev.me>,
 "Dr. David Alan Gilbert" <linux@...blig.org>,
 Dong Chenchen <dongchenchen2@...wei.com>, Oscar Maes <oscmaes92@...il.com>
Subject: Re: [PATCH net] net: vlan: sync VLAN features with lower device

On 10/21/25 11:56 AM, Hangbin Liu wrote:
> After registering a VLAN device and setting its feature flags, we need to
> synchronize the VLAN features with the lower device. For example, the VLAN
> device does not have the NETIF_F_LRO flag, it should be synchronized with
> the lower device based on the NETIF_F_UPPER_DISABLES definition.
> 
> As the dev->vlan_features has changed, we need to call
> netdev_change_features(). The caller must run after netdev_upper_dev_link()
> links the lower devices, so this patch adds the netdev_change_features()
> call in register_vlan_dev().


> 
> Signed-off-by: Hangbin Liu <liuhangbin@...il.com>
> ---
> 
> I’m not sure what the proper Fixes tag should be, so I’ve left it blank for
> now. If anyone has a clue, please let me know.

Apparently the issue is there since fd867d51f889aec11cca235ebb008578780d052d

> 
> ---
>  net/8021q/vlan.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/net/8021q/vlan.c b/net/8021q/vlan.c
> index fda3a80e9340..4857fb0ee11d 100644
> --- a/net/8021q/vlan.c
> +++ b/net/8021q/vlan.c
> @@ -193,6 +193,8 @@ int register_vlan_dev(struct net_device *dev, struct netlink_ext_ack *extack)
>  	vlan_group_set_device(grp, vlan->vlan_proto, vlan_id, dev);
>  	grp->nr_vlan_devs++;
>  
> +	netdev_change_features(dev);

Is this just for NETIF_F_LRO? it feels a bit overkill for single flag.
Also, why netdev_change_features() (vs netdev_update_features())?> +
>  	return 0;
>  
>  out_unregister_netdev: