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 <james.hug...@raspberrypi.org> --- Changes v3 - Added the dev_kfree_skb_any call to ensure skb is deallocated as when returning NULL the caller won't deallocate v4 - Fix typo in comment (reallocate to deallocate) drivers/net/usb/smsc95xx.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/net/usb/smsc95xx.c b/drivers/net/usb/smsc95xx.c index df60c98..f6661e3 100644 --- a/drivers/net/usb/smsc95xx.c +++ b/drivers/net/usb/smsc95xx.c @@ -2067,13 +2067,13 @@ 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); + /* Make writable and expand header space by overhead if required */ + if (skb_cow_head(skb, overhead)) { + /* Must deallocate here as returning NULL to indicate error + * means the skb won't be deallocated in the caller. + */ dev_kfree_skb_any(skb); - skb = skb2; - if (!skb) - return NULL; + return NULL; } if (csum) { -- 2.9.3