libertas if_usb: Fix crash on 64-bit machines

On a 64-bit kernel, skb->tail is an offset, not a pointer. The libertas
usb driver passes it to usb_fill_bulk_urb() anyway, causing interesting
crashes. Fix that by using skb->data instead.

This highlights a problem with usb_fill_bulk_urb(). It doesn't notice
when dma_map_single() fails and return the error to its caller as it
should. In fact it _can't_ currently return the error, since it returns
void.

So this problem was showing up only at unmap time, after we'd already
suffered memory corruption by doing DMA to a bogus address.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Cc: stable@kernel.org
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/drivers/net/wireless/libertas/if_usb.c b/drivers/net/wireless/libertas/if_usb.c
index 92bc8c5f1ca216e337f4897a9b1cdbd44ec3a289..3fac4efa5ac896dd06d9e3d1cbc216072fde0ecf 100644 (file)
--- a/drivers/net/wireless/libertas/if_usb.c
+++ b/drivers/net/wireless/libertas/if_usb.c
@@ -508,7 +508,7 @@ static int __if_usb_submit_rx_urb(struct if_usb_card *cardp,
        /* Fill the receive configuration URB and initialise the Rx call back */
        usb_fill_bulk_urb(cardp->rx_urb, cardp->udev,
                          usb_rcvbulkpipe(cardp->udev, cardp->ep_in),
-                         (void *) (skb->tail + (size_t) IPFIELD_ALIGN_OFFSET),
+                         skb->data + IPFIELD_ALIGN_OFFSET,
                          MRVDRV_ETH_RX_PACKET_BUFFER_SIZE, callbackfn,
                          cardp);