Re: [PATCH net-next 1/7] net: ethtool: prevent flow steering to RSS contexts which don't exist

[Gal Pressman <gal@nvidia.com>]

On 07/02/2025 1:53, Jakub Kicinski wrote:
> Since commit 42dc431f5d0e ("ethtool: rss: prevent rss ctx deletion
> when in use") we prevent removal of RSS contexts pointed to by

Nit: I would try to avoid the line break in the middle of the cited commit.

> existing flow rules. Core should also prevent creation of rules
> which point to RSS context which don't exist in the first place.
> 
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> ---
> CC: ecree.xilinx@gmail.com
> CC: gal@nvidia.com
> ---
>  net/ethtool/ioctl.c | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
> index 7609ce2b2c5e..98b7dcea207a 100644
> --- a/net/ethtool/ioctl.c
> +++ b/net/ethtool/ioctl.c
> @@ -993,10 +993,14 @@ static noinline_for_stack int ethtool_set_rxnfc(struct net_device *dev,
>  		return rc;
>  
>  	/* Nonzero ring with RSS only makes sense if NIC adds them together */

This comment should be moved inside the if statement.

> -	if (cmd == ETHTOOL_SRXCLSRLINS && info.fs.flow_type & FLOW_RSS &&
> -	    !ops->cap_rss_rxnfc_adds &&
> -	    ethtool_get_flow_spec_ring(info.fs.ring_cookie))
> -		return -EINVAL;
> +	if (cmd == ETHTOOL_SRXCLSRLINS && info.fs.flow_type & FLOW_RSS) {
> +		if (!ops->cap_rss_rxnfc_adds &&
> +		    ethtool_get_flow_spec_ring(info.fs.ring_cookie))
> +			return -EINVAL;
> +
> +		if (!xa_load(&dev->ethtool->rss_ctx, info.rss_context))

Accessing rss_ctx without rss_lock?

> +			return -EINVAL;
> +	}
>  
>  	if (cmd == ETHTOOL_SRXFH && ops->get_rxfh) {
>  		struct ethtool_rxfh_param rxfh = {};