hyperv: Fix a bug in netvsc_start_xmit()

After the packet is successfully sent, we should not touch the skb
as it may have been freed. This patch is based on the work done by
Long Li <longli@microsoft.com>.

In this version of the patch I have fixed issues pointed out by David.
David, please queue this up for stable.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Tested-by: Long Li <longli@microsoft.com>
Tested-by: Sitsofe Wheeler <sitsofe@yahoo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index a9c5eaadc426..0fcb5e7eb073 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -387,6 +387,7 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
         int  hdr_offset;
         u32 net_trans_info;
         u32 hash;
+        u32 skb_length = skb->len;
 
 
         /* We will atmost need two pages to describe the rndis
@@ -562,7 +563,7 @@ do_send:
 
 drop:
         if (ret == 0) {
-                net->stats.tx_bytes += skb->len;
+                net->stats.tx_bytes += skb_length;
                 net->stats.tx_packets++;
         } else {
                 kfree(packet);