gro: reset vlan_tci on reuse

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>
[PG: taken from v2.6.32.y stable, commit 5aff28abc7e]
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/net/core/dev.c b/net/core/dev.c
index 7daff00c9e2fc36caf1c2e60a04461086afb136b..2aaf2e610f92decb3f68c1a7c082efe4db60f8aa 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2823,6 +2823,7 @@ void napi_reuse_skb(struct napi_struct *napi, struct sk_buff *skb)
 {
        __skb_pull(skb, skb_headlen(skb));
        skb_reserve(skb, NET_IP_ALIGN - skb_headroom(skb));
+       skb->vlan_tci = 0;
        skb->dev = napi->dev;
        skb->skb_iif = 0;