[PATCH] hv_netvsc: Add comment of netvsc_xdp_xmit()

[PATCH] hv_netvsc: Add comment of netvsc_xdp_xmit()

[Jiasheng Jiang]

Adding comment to avoid the misusing of netvsc_xdp_xmit().
Otherwise the value of skb->queue_mapping could be 0 and
then the return value of skb_get_rx_queue() could be MAX_U16
cause by overflow.

Fixes: 351e158 ("hv_netvsc: Add XDP support")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
---
 drivers/net/hyperv/netvsc_drv.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index f682a55..ac9529c 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -803,6 +803,7 @@ void netvsc_linkstatus_callback(struct net_device *net,
 	schedule_delayed_work(&ndev_ctx->dwork, 0);
 }
 
+/* This function should only be called after skb_record_rx_queue() */
 static void netvsc_xdp_xmit(struct sk_buff *skb, struct net_device *ndev)
 {
 	int rc;
-- 
2.7.4

RE: [PATCH] hv_netvsc: Add comment of netvsc_xdp_xmit()

[Haiyang Zhang]

> -----Original Message-----
> From: Jiasheng Jiang <jiasheng@iscas.ac.cn>
> Sent: Wednesday, October 13, 2021 9:26 PM
> To: KY Srinivasan <kys@microsoft.com>; Haiyang Zhang
> <haiyangz@microsoft.com>; Stephen Hemminger <sthemmin@microsoft.com>;
> wei.liu@kernel.org; Dexuan Cui <decui@microsoft.com>;
> davem@davemloft.net; kuba@kernel.org
> Cc: linux-hyperv@vger.kernel.org; netdev@vger.kernel.org; linux-
> kernel@vger.kernel.org; bpf@vger.kernel.org; Jiasheng Jiang
> <jiasheng@iscas.ac.cn>
> Subject: [PATCH] hv_netvsc: Add comment of netvsc_xdp_xmit()
> 
> Adding comment to avoid the misusing of netvsc_xdp_xmit().
> Otherwise the value of skb->queue_mapping could be 0 and
> then the return value of skb_get_rx_queue() could be MAX_U16
> cause by overflow.
> 
> Fixes: 351e158 ("hv_netvsc: Add XDP support")
> Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
> ---
>  drivers/net/hyperv/netvsc_drv.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/net/hyperv/netvsc_drv.c
> b/drivers/net/hyperv/netvsc_drv.c
> index f682a55..ac9529c 100644
> --- a/drivers/net/hyperv/netvsc_drv.c
> +++ b/drivers/net/hyperv/netvsc_drv.c
> @@ -803,6 +803,7 @@ void netvsc_linkstatus_callback(struct net_device
> *net,
>  	schedule_delayed_work(&ndev_ctx->dwork, 0);
>  }
> 
> +/* This function should only be called after skb_record_rx_queue() */
>  static void netvsc_xdp_xmit(struct sk_buff *skb, struct net_device
> *ndev)
>  {

Thanks.

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

Re: [PATCH] hv_netvsc: Add comment of netvsc_xdp_xmit()

[patchwork-bot+netdevbpf]

Hello:

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

On Thu, 14 Oct 2021 01:26:26 +0000 you wrote:
> Adding comment to avoid the misusing of netvsc_xdp_xmit().
> Otherwise the value of skb->queue_mapping could be 0 and
> then the return value of skb_get_rx_queue() could be MAX_U16
> cause by overflow.
> 
> Fixes: 351e158 ("hv_netvsc: Add XDP support")
> Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
> 
> [...]

Here is the summary with links:
  - hv_netvsc: Add comment of netvsc_xdp_xmit()
    https://git.kernel.org/netdev/net-next/c/78e0a006914b

You are awesome, thank you!
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