hyperv: Fix a bug in netvsc_start_xmit()

[ Upstream commit dedb845ded56ded1c62f5398a94ffa8615d4592d ]

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index d6fce97..3c1c33c 100644 (file)
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -146,6 +146,7 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
        struct hv_netvsc_packet *packet;
        int ret;
        unsigned int i, num_pages, npg_data;
+       u32 skb_length = skb->len;
 
        /* Add multipages for skb->data and additional 2 for RNDIS */
        npg_data = (((unsigned long)skb->data + skb_headlen(skb) - 1)
@@ -216,7 +217,7 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
        ret = rndis_filter_send(net_device_ctx->device_ctx,
                                  packet);
        if (ret == 0) {
-               net->stats.tx_bytes += skb->len;
+               net->stats.tx_bytes += skb_length;
                net->stats.tx_packets++;
        } else {
                kfree(packet);