3.12-stable review patch.  If anyone has any objections, please let me know.

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

From: Ivan Vecera <ivec...@redhat.com>

commit 85aec73d595b8847f9c4ea571deb127913f0d508 upstream.

If build_skb fails the memory associated with the ring buffer is freed but
the ri->data member is not zeroed in this case. This causes a double-free
of this memory in tg3_free_rings->... path. The patch moves this block after
setting ri->data to NULL.
It would be nice to fix this bug also in stable >= v3.4 trees.

Cc: Nithin Nayak Sujir <nsu...@broadcom.com>
Cc: Michael Chan <mc...@broadcom.com>
Signed-off-by: Ivan Vecera <ivec...@redhat.com>
Acked-by: Michael Chan <mc...@broadcom.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 drivers/net/ethernet/broadcom/tg3.c |   12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

--- a/drivers/net/ethernet/broadcom/tg3.c
+++ b/drivers/net/ethernet/broadcom/tg3.c
@@ -6848,12 +6848,6 @@ static int tg3_rx(struct tg3_napi *tnapi
                        pci_unmap_single(tp->pdev, dma_addr, skb_size,
                                         PCI_DMA_FROMDEVICE);
 
-                       skb = build_skb(data, frag_size);
-                       if (!skb) {
-                               tg3_frag_free(frag_size != 0, data);
-                               goto drop_it_no_recycle;
-                       }
-                       skb_reserve(skb, TG3_RX_OFFSET(tp));
                        /* Ensure that the update to the data happens
                         * after the usage of the old DMA mapping.
                         */
@@ -6861,6 +6855,12 @@ static int tg3_rx(struct tg3_napi *tnapi
 
                        ri->data = NULL;
 
+                       skb = build_skb(data, frag_size);
+                       if (!skb) {
+                               tg3_frag_free(frag_size != 0, data);
+                               goto drop_it_no_recycle;
+                       }
+                       skb_reserve(skb, TG3_RX_OFFSET(tp));
                } else {
                        tg3_recycle_rx(tnapi, tpr, opaque_key,
                                       desc_idx, *post_ptr);


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