Re: [PATCH net] net: ethernet: cadence: fix socket buffer corruption problem

[Claudiu.Beznea]

Hi Tristram,

Could you, please, tell me if the above variable was false in your case?

bool cloned = skb_cloned(*skb) || skb_header_cloned(*skb);

If yes, then, the proper fix would be as follows:

diff --git a/drivers/net/ethernet/cadence/macb_main.c 
b/drivers/net/ethernet/cadence/macb_main.c
index 8f5bf9166c11..492a8e1a34cd 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -1690,7 +1690,7 @@ static int macb_pad_and_fcs(struct sk_buff **skb, struct 
net_device *ndev)
                padlen += ETH_FCS_LEN;
        }
 
-       if (!cloned && headroom + tailroom >= padlen) {
+       if (!cloned && headroom + tailroom >= ETH_FCS_LEN) {
                (*skb)->data = memmove((*skb)->head, (*skb)->data, (*skb)->len);
                skb_set_tail_pointer(*skb, (*skb)->len);
        } else {

Could you please check if it works in your case (and without your patch)?

Thank you,
Claudiu Beznea

On 25.10.2018 00:51, tristram...@microchip.com wrote:
> From: Tristram Ha <tristram...@microchip.com>
> 
> Socket buffer is not re-created when headroom is 2 and tailroom is 1.
> 
> Signed-off-by: Tristram Ha <tristram...@microchip.com>
> ---
>  drivers/net/ethernet/cadence/macb_main.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/cadence/macb_main.c 
> b/drivers/net/ethernet/cadence/macb_main.c
> index 8f5bf91..1d86b4d 100644
> --- a/drivers/net/ethernet/cadence/macb_main.c
> +++ b/drivers/net/ethernet/cadence/macb_main.c
> @@ -1684,7 +1684,7 @@ static int macb_pad_and_fcs(struct sk_buff **skb, 
> struct net_device *ndev)
>                       padlen = 0;
>               /* No room for FCS, need to reallocate skb. */
>               else
> -                     padlen = ETH_FCS_LEN - tailroom;
> +                     padlen = ETH_FCS_LEN;
>       } else {
>               /* Add room for FCS. */
>               padlen += ETH_FCS_LEN;
>