[11/27] gro: reset vlan_tci on reuse

[Greg KH <gregkh@suse.de>]

2.6.32-longterm review patch.  If anyone has any objections, please let me know.

------------------

This one liner is part of upstream
commit 3701e51382a026cba10c60b03efabe534fba4ca4
Author: Jesse Gross <jesse@nicira.com>

    vlan: Centralize handling of hardware acceleration.

The bulk of that commit is a rework of the hardware assisted vlan tagging
driver interface, and as such doesn't classify for -stable inclusion. The fix
that is needed is a part of that commit but can work independently of the
rest.

This patch can avoid panics on the 2.6.32.y -stable kernels and is in the same
spirit as mainline commits
66c46d7 gro: Reset dev pointer on reuse
6d152e2 gro: reset skb_iif on reuse
which are already in -stable.

For drivers using the vlan_gro_frags() interface, a packet with an invalid tci
leads to GRO_DROP and napi_reuse_skb(). The skb has to be sanitized before
being reused or we may send an skb with an invalid vlan_tci field up the stack
where it is not expected.

Signed-off-by: Benjamin Poirier <bpoirier@suse.de>
Cc: Jesse Gross <jesse@nicira.com>
Acked-by: David S. Miller <davem@davemloft.net>

---
 net/core/dev.c |    1 +
 1 file changed, 1 insertion(+)

--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2614,6 +2614,7 @@ void napi_reuse_skb(struct napi_struct *
 {
 	__skb_pull(skb, skb_headlen(skb));
 	skb_reserve(skb, NET_IP_ALIGN - skb_headroom(skb));
+	skb->vlan_tci = 0;
 	skb->dev = napi->dev;
 	skb->iif = 0;