[PATCH net-next] net: hv_netvsc: reject RSS hash key programming without RX indirection table

[PATCH net-next] net: hv_netvsc: reject RSS hash key programming without RX indirection table

[Aditya Garg]

RSS configuration requires a valid RX indirection table. When the device
reports a single receive queue, rndis_filter_device_add() does not
allocate an indirection table, accepting RSS hash key updates in this
state leads to a hang.

Fix this by gating netvsc_set_rxfh() on ndc->rx_table_sz and return
-EOPNOTSUPP when the table is absent. This aligns set_rxfh with the device
capabilities and prevents incorrect behavior.

Fixes: 962f3fee83a4 ("netvsc: add ethtool ops to get/set RSS key")
Signed-off-by: Aditya Garg <gargaditya@linux.microsoft.com>
Reviewed-by: Dipayaan Roy <dipayanroy@linux.microsoft.com>
---
 drivers/net/hyperv/netvsc_drv.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 3d47d749ef9f..cbd52cb79268 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -1750,6 +1750,9 @@ static int netvsc_set_rxfh(struct net_device *dev,
 	    rxfh->hfunc != ETH_RSS_HASH_TOP)
 		return -EOPNOTSUPP;
 
+	if (!ndc->rx_table_sz)
+		return -EOPNOTSUPP;
+
 	rndis_dev = ndev->extension;
 	if (rxfh->indir) {
 		for (i = 0; i < ndc->rx_table_sz; i++)
-- 
2.43.0

Re: [PATCH net-next] net: hv_netvsc: reject RSS hash key programming without RX indirection table

[Dipayaan Roy]

On Mon, Jan 12, 2026 at 02:01:33AM -0800, Aditya Garg wrote:
> RSS configuration requires a valid RX indirection table. When the device
> reports a single receive queue, rndis_filter_device_add() does not
> allocate an indirection table, accepting RSS hash key updates in this
> state leads to a hang.
> 
> Fix this by gating netvsc_set_rxfh() on ndc->rx_table_sz and return
> -EOPNOTSUPP when the table is absent. This aligns set_rxfh with the device
> capabilities and prevents incorrect behavior.
> 
> Fixes: 962f3fee83a4 ("netvsc: add ethtool ops to get/set RSS key")
> Signed-off-by: Aditya Garg <gargaditya@linux.microsoft.com>
> Reviewed-by: Dipayaan Roy <dipayanroy@linux.microsoft.com>
> ---
>  drivers/net/hyperv/netvsc_drv.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
> index 3d47d749ef9f..cbd52cb79268 100644
> --- a/drivers/net/hyperv/netvsc_drv.c
> +++ b/drivers/net/hyperv/netvsc_drv.c
> @@ -1750,6 +1750,9 @@ static int netvsc_set_rxfh(struct net_device *dev,
>  	    rxfh->hfunc != ETH_RSS_HASH_TOP)
>  		return -EOPNOTSUPP;
>  
> +	if (!ndc->rx_table_sz)
> +		return -EOPNOTSUPP;
> +
>  	rndis_dev = ndev->extension;
>  	if (rxfh->indir) {
>  		for (i = 0; i < ndc->rx_table_sz; i++)
> -- 
> 2.43.0
>

LGTM.

Reviewed-by: Dipayaan Roy <dipayanroy@linux.microsoft.com>

RE: [PATCH net-next] net: hv_netvsc: reject RSS hash key programming without RX indirection table

[Haiyang Zhang]

> -----Original Message-----
> From: Aditya Garg <gargaditya@linux.microsoft.com>
> Sent: Monday, January 12, 2026 5:02 AM
> To: KY Srinivasan <kys@microsoft.com>; Haiyang Zhang
> <haiyangz@microsoft.com>; wei.liu@kernel.org; Dexuan Cui
> <DECUI@microsoft.com>; Long Li <longli@microsoft.com>;
> andrew+netdev@lunn.ch; davem@davemloft.net; edumazet@google.com;
> kuba@kernel.org; pabeni@redhat.com; stephen@networkplumber.org; linux-
> hyperv@vger.kernel.org; netdev@vger.kernel.org; linux-
> kernel@vger.kernel.org; dipayanroy@linux.microsoft.com;
> ssengar@linux.microsoft.com; shradhagupta@linux.microsoft.com;
> ernis@linux.microsoft.com; Aditya Garg <gargaditya@microsoft.com>;
> gargaditya@linux.microsoft.com
> Subject: [PATCH net-next] net: hv_netvsc: reject RSS hash key programming
> without RX indirection table
> 
> RSS configuration requires a valid RX indirection table. When the device
> reports a single receive queue, rndis_filter_device_add() does not
> allocate an indirection table, accepting RSS hash key updates in this
> state leads to a hang.
> 
> Fix this by gating netvsc_set_rxfh() on ndc->rx_table_sz and return
> -EOPNOTSUPP when the table is absent. This aligns set_rxfh with the device
> capabilities and prevents incorrect behavior.
> 
> Fixes: 962f3fee83a4 ("netvsc: add ethtool ops to get/set RSS key")
> Signed-off-by: Aditya Garg <gargaditya@linux.microsoft.com>
> Reviewed-by: Dipayaan Roy <dipayanroy@linux.microsoft.com>

Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>

Re: [PATCH net-next] net: hv_netvsc: reject RSS hash key programming without RX indirection table

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Mon, 12 Jan 2026 02:01:33 -0800 you wrote:
> RSS configuration requires a valid RX indirection table. When the device
> reports a single receive queue, rndis_filter_device_add() does not
> allocate an indirection table, accepting RSS hash key updates in this
> state leads to a hang.
> 
> Fix this by gating netvsc_set_rxfh() on ndc->rx_table_sz and return
> -EOPNOTSUPP when the table is absent. This aligns set_rxfh with the device
> capabilities and prevents incorrect behavior.
> 
> [...]

Here is the summary with links:
  - [net-next] net: hv_netvsc: reject RSS hash key programming without RX indirection table
    https://git.kernel.org/netdev/net/c/d23564955811

You are awesome, thank you!
-- 
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