In my patch c194992cbe71c20bb3623a566af8d11b0bfaa721 I didn't fix the skge bug correctly. The value of the new mapping (not old) was passed to pci_unmap_single. If we enable CONFIG_DMA_API_DEBUG, it results in this warning: WARNING: CPU: 0 PID: 0 at lib/dma-debug.c:986 check_sync+0x4c4/0x580() skge 0000:02:07.0: DMA-API: device driver tries to sync DMA memory it has not allocated [device address=0x000000023a0096c0] [size=1536 bytes] This patch makes the skge driver pass the correct value to pci_unmap_single and fixes the warning. It copies the old descriptor to on-stack variable "ee" and unmaps it if mapping of the new descriptor succeeded. This patch should be backported to 3.11-stable. Signed-off-by: Mikulas Patocka Reported-by: Francois Romieu Tested-by: Mikulas Patocka --- drivers/net/ethernet/marvell/skge.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) Index: linux-3.11.1-fast/drivers/net/ethernet/marvell/skge.c =================================================================== --- linux-3.11.1-fast.orig/drivers/net/ethernet/marvell/skge.c 2013-09-20 16:13:24.000000000 +0200 +++ linux-3.11.1-fast/drivers/net/ethernet/marvell/skge.c 2013-09-20 16:18:13.000000000 +0200 @@ -3086,13 +3086,16 @@ static struct sk_buff *skge_rx_get(struc PCI_DMA_FROMDEVICE); skge_rx_reuse(e, skge->rx_buf_size); } else { + struct skge_element ee; struct sk_buff *nskb; nskb = netdev_alloc_skb_ip_align(dev, skge->rx_buf_size); if (!nskb) goto resubmit; - skb = e->skb; + ee = *e; + + skb = ee.skb; prefetch(skb->data); if (skge_rx_setup(skge, e, nskb, skge->rx_buf_size) < 0) { @@ -3101,8 +3104,8 @@ static struct sk_buff *skge_rx_get(struc } pci_unmap_single(skge->hw->pdev, - dma_unmap_addr(e, mapaddr), - dma_unmap_len(e, maplen), + dma_unmap_addr(&ee, mapaddr), + dma_unmap_len(&ee, maplen), PCI_DMA_FROMDEVICE); }