[ 125/173] solos-pci: fix double-free of TX skb in DMA mode

[Ben Hutchings]

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

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

From: David Woodhouse <dwmw2@xxxxxxxxxxxxx>

commit cae49ede00ec3d0cda290b03fee55b72b49efc11 upstream.

We weren't clearing card->tx_skb[port] when processing the TX done interrupt.
If there wasn't another skb ready to transmit immediately, this led to a
double-free because we'd free it *again* next time we did have a packet to
send.

Signed-off-by: David Woodhouse <David.Woodhouse@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/atm/solos-pci.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/atm/solos-pci.c b/drivers/atm/solos-pci.c
index 6619a8a..c909b7b 100644
--- a/drivers/atm/solos-pci.c
+++ b/drivers/atm/solos-pci.c
@@ -945,10 +945,11 @@ static uint32_t fpga_tx(struct solos_card *card)
 	for (port = 0; tx_pending; tx_pending >>= 1, port++) {
 		if (tx_pending & 1) {
 			struct sk_buff *oldskb = card->tx_skb[port];
-			if (oldskb)
+			if (oldskb) {
 				pci_unmap_single(card->dev, SKB_CB(oldskb)->dma_addr,
 						 oldskb->len, PCI_DMA_TODEVICE);
-
+				card->tx_skb[port] = NULL;
+			}
 			spin_lock(&card->tx_queue_lock);
 			skb = skb_dequeue(&card->tx_queue[port]);
 			if (!skb)


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