[v2.6.34-stable 024/165] atm: br2684: Fix oops due to skb->dev being NULL

[Paul Gortmaker]

From: Daniel Schwierzeck <daniel.schwierzeck@xxxxxxxxxxxxxx>

                   -------------------
    This is a commit scheduled for the next v2.6.34 longterm release.
    http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git
    If you see a problem with using this for longterm, please comment.
                   -------------------

commit fbe5e29ec1886967255e76946aaf537b8cc9b81e upstream.

This oops have been already fixed with commit

    27141666b69f535a4d63d7bc6d9e84ee5032f82a

    atm: [br2684] Fix oops due to skb->dev being NULL

    It happens that if a packet arrives in a VC between the call to open it on
    the hardware and the call to change the backend to br2684, br2684_regvcc
    processes the packet and oopses dereferencing skb->dev because it is
    NULL before the call to br2684_push().

but have been introduced again with commit

    b6211ae7f2e56837c6a4849316396d1535606e90

    atm: Use SKB queue and list helpers instead of doing it by-hand.

Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@xxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
---
 net/atm/br2684.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/net/atm/br2684.c b/net/atm/br2684.c
index f3bae14..e9b5677 100644
--- a/net/atm/br2684.c
+++ b/net/atm/br2684.c
@@ -522,12 +522,13 @@ static int br2684_regvcc(struct atm_vcc *atmvcc, void __user * arg)
 	spin_unlock_irqrestore(&rq->lock, flags);
 
 	skb_queue_walk_safe(&queue, skb, tmp) {
-		struct net_device *dev = skb->dev;
+		struct net_device *dev;
+
+		br2684_push(atmvcc, skb);
+		dev = skb->dev;
 
 		dev->stats.rx_bytes -= skb->len;
 		dev->stats.rx_packets--;
-
-		br2684_push(atmvcc, skb);
 	}
 	__module_get(THIS_MODULE);
 	return 0;
-- 
1.7.12.rc2

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