Re: [PATCH net-next 4/4] netdev: don't use dev->flags for IFF_UP

[Bobby Eshleman <bobbyeshleman@gmail.com>]

On Tue, Jun 09, 2026 at 12:08:04PM -0700, Jakub Kicinski wrote:
> dev->flags are not technically ops lock protected. The IFF_UP flag
> will not change when dev->lock is held, but other flags may change
> so KCSAN would probably not be impressed. Because of this we added
> a dedicated dev->up which is safe to read under dev->lock.
> 
> qstats want to make sure device is up, use dev->up.
> 
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> ---
>  net/core/netdev-genl.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
> index 18046ad0f883..745e2eb6c9af 100644
> --- a/net/core/netdev-genl.c
> +++ b/net/core/netdev-genl.c
> @@ -773,7 +773,7 @@ netdev_nl_stats_by_queue(struct net_device *netdev, struct sk_buff *rsp,
>  	const struct netdev_stat_ops *ops = netdev->stat_ops;
>  	int i, err;
>  
> -	if (!(netdev->flags & IFF_UP))
> +	if (!netdev->up)
>  		return 0;
>  
>  	i = ctx->rxq_idx;
> -- 
> 2.54.0
> 
> 

Reviewed-by: Bobby Eshleman <bobbyeshleman@meta.com>