On Tue, 2017-04-18 at 18:17 +0100, James Hughes wrote:
> The driver was failing to check that the SKB wasn't cloned
> before adding checksum data.
> Replace existing handling to extend/copy the header buffer
> with skb_cow_head.
>
> Signed-off-by: James Hughes <[email protected]>
> ---
> Changes in v2
> - Changed skb_cow to skb_cow_head as suggested by netdev list
>
>
> drivers/net/usb/smsc95xx.c | 10 +++-------
> 1 file changed, 3 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/net/usb/smsc95xx.c b/drivers/net/usb/smsc95xx.c
> index df60c98..094f0ee 100644
> --- a/drivers/net/usb/smsc95xx.c
> +++ b/drivers/net/usb/smsc95xx.c
> @@ -2067,13 +2067,9 @@ static struct sk_buff *smsc95xx_tx_fixup(struct usbnet
> *dev,
> /* We do not advertise SG, so skbs should be already linearized */
> BUG_ON(skb_shinfo(skb)->nr_frags);
>
> - if (skb_headroom(skb) < overhead) {
> - struct sk_buff *skb2 = skb_copy_expand(skb,
> - overhead, 0, flags);
> - dev_kfree_skb_any(skb);
> - skb = skb2;
> - if (!skb)
> - return NULL;
> + /* Make writable and expand header space by overhead if required */
> + if (skb_cow_head(skb, overhead)) {
I believe you still need to
dev_kfree_skb_any(skb);
> + return NULL;
> }
>
> if (csum) {
