[PATCH] [40/106] gro: Reset dev pointer on reuse

From: Andi Kleen
Date: Tue Apr 26 2011 - 17:33:40 EST


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

------------------
From: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>

commit 66c46d741e2e60f0e8b625b80edb0ab820c46d7a upstream.

On older kernels the VLAN code may zero skb->dev before dropping
it and causing it to be reused by GRO.

Unfortunately we didn't reset skb->dev in that case which causes
the next GRO user to get a bogus skb->dev pointer.

This particular problem no longer happens with the current upstream
kernel due to changes in VLAN processing.

However, for correctness we should still reset the skb->dev pointer
in the GRO reuse function in case a future user does the same thing.

Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Brandon Philips <bphilips@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>

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

Index: linux-2.6.35.y/net/core/dev.c
===================================================================
--- linux-2.6.35.y.orig/net/core/dev.c
+++ linux-2.6.35.y/net/core/dev.c
@@ -3231,6 +3231,7 @@ void napi_reuse_skb(struct napi_struct *
{
__skb_pull(skb, skb_headlen(skb));
skb_reserve(skb, NET_IP_ALIGN - skb_headroom(skb));
+ skb->dev = napi->dev;

napi->skb = skb;
}
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