On Tue, 2014-03-04 at 08:46 -0800, Soren Brinkmann wrote: > With CONFIG_DMA_API_DEBUG enabled the following warning is printed: > WARNING: CPU: 0 PID: 619 at lib/dma-debug.c:1101 check_unmap+0x758/0x894() > macb e000b000.ethernet: DMA-API: device driver failed to check map > error[device address=0x000000002d171c02] [size=322 bytes] [mapped as single] > Modules linked in: > CPU: 0 PID: 619 Comm: udhcpc Not tainted > 3.14.0-rc3-xilinx-00219-gd158fc7f36a2 #63 > [<c001516c>] (unwind_backtrace) from [<c0011df8>] (show_stack+0x10/0x14) > [<c0011df8>] (show_stack) from [<c03c7714>] (dump_stack+0x7c/0xc8) > [<c03c7714>] (dump_stack) from [<c00245cc>] (warn_slowpath_common+0x60/0x84) > [<c00245cc>] (warn_slowpath_common) from [<c0024670>] > (warn_slowpath_fmt+0x2c/0x3c) > [<c0024670>] (warn_slowpath_fmt) from [<c0228244>] (check_unmap+0x758/0x894) > [<c0228244>] (check_unmap) from [<c0228588>] (debug_dma_unmap_page+0x64/0x70) > [<c0228588>] (debug_dma_unmap_page) from [<c02aba64>] > (macb_interrupt+0x1f8/0x2dc) > [<c02aba64>] (macb_interrupt) from [<c006c6e4>] > (handle_irq_event_percpu+0x2c/0x178) > [<c006c6e4>] (handle_irq_event_percpu) from [<c006c86c>] > (handle_irq_event+0x3c/0x5c) > [<c006c86c>] (handle_irq_event) from [<c006f548>] > (handle_fasteoi_irq+0xb8/0x100) > [<c006f548>] (handle_fasteoi_irq) from [<c006c148>] > (generic_handle_irq+0x20/0x30) > [<c006c148>] (generic_handle_irq) from [<c000f35c>] (handle_IRQ+0x64/0x8c) > [<c000f35c>] (handle_IRQ) from [<c0008528>] (gic_handle_irq+0x3c/0x60) > [<c0008528>] (gic_handle_irq) from [<c0012904>] (__irq_svc+0x44/0x78) > Exception stack(0xed197f60 to 0xed197fa8) > 7f60: 00000134 60000013 bd94362e bd94362e be96b37c 00000014 fffffd72 00000122 > 7f80: c000ebe4 ed196000 00000000 00000011 c032c0d8 ed197fa8 c0064008 c000ea20 > 7fa0: 60000013 ffffffff > [<c0012904>] (__irq_svc) from [<c000ea20>] (ret_fast_syscall+0x0/0x48) > ---[ end trace 478f921d0d542d1e ]--- > Mapped at: > [<c0227184>] debug_dma_map_page+0x48/0x11c > [<c02aaca0>] macb_start_xmit+0x184/0x2a8 > [<c03143c0>] dev_hard_start_xmit+0x334/0x470 > [<c032c09c>] sch_direct_xmit+0x78/0x2f8 > [<c0314814>] __dev_queue_xmit+0x318/0x708 > > due to missing checks of the dma mapping. Add the appropriate checks to fix > this. > > Signed-off-by: Soren Brinkmann <[email protected]>
Reviewed-by: Ben Hutchings <[email protected]> > --- > v3: > - move tx_head pointer increment to after the DMA error check > v2: > - unlock spinlock when mapping error is detected in start_xmit() > - use kfree_skb() instead of dev_kfree_skb in start_xmit() > --- > drivers/net/ethernet/cadence/macb.c | 14 ++++++++++++-- > 1 file changed, 12 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/ethernet/cadence/macb.c > b/drivers/net/ethernet/cadence/macb.c > index 3190d38e16fb..1f03e2041e86 100644 > --- a/drivers/net/ethernet/cadence/macb.c > +++ b/drivers/net/ethernet/cadence/macb.c > @@ -632,11 +632,16 @@ static void gem_rx_refill(struct macb *bp) > "Unable to allocate sk_buff\n"); > break; > } > - bp->rx_skbuff[entry] = skb; > > /* now fill corresponding descriptor entry */ > paddr = dma_map_single(&bp->pdev->dev, skb->data, > bp->rx_buffer_size, > DMA_FROM_DEVICE); > + if (dma_mapping_error(&bp->pdev->dev, paddr)) { > + dev_kfree_skb(skb); > + break; > + } > + > + bp->rx_skbuff[entry] = skb; > > if (entry == RX_RING_SIZE - 1) > paddr |= MACB_BIT(RX_WRAP); > @@ -1036,11 +1041,15 @@ static int macb_start_xmit(struct sk_buff *skb, > struct net_device *dev) > } > > entry = macb_tx_ring_wrap(bp->tx_head); > - bp->tx_head++; > netdev_vdbg(bp->dev, "Allocated ring entry %u\n", entry); > mapping = dma_map_single(&bp->pdev->dev, skb->data, > len, DMA_TO_DEVICE); > + if (dma_mapping_error(&bp->pdev->dev, mapping)) { > + kfree_skb(skb); > + goto unlock; > + } > > + bp->tx_head++; > tx_skb = &bp->tx_skb[entry]; > tx_skb->skb = skb; > tx_skb->mapping = mapping; > @@ -1066,6 +1075,7 @@ static int macb_start_xmit(struct sk_buff *skb, struct > net_device *dev) > if (CIRC_SPACE(bp->tx_head, bp->tx_tail, TX_RING_SIZE) < 1) > netif_stop_queue(dev); > > +unlock: > spin_unlock_irqrestore(&bp->lock, flags); > > return NETDEV_TX_OK; -- Ben Hutchings For every complex problem there is a solution that is simple, neat, and wrong.
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