From fe24ba082b8483c81f546d24e40a55624295b85d Mon Sep 17 00:00:00 2001 From: Florian Fainelli Date: Mon, 8 Sep 2014 11:37:51 -0700 Subject: [PATCH] net: systemport: check harder for out of memory conditions There is a potential case where we might be failing to refill a control block, leaving it with both a NULL skb pointer *and* a NULL dma_unmap_addr. The way we process incoming packets, by first calling dma_unmap_single(), and then only checking for a potential NULL skb can lead to situations where do pass a NULL dma_unmap_addr() to dma_unmap_single(), resulting in an oops. Fix this my moving the NULL skb check earlier, since no backing skb also means no corresponding DMA mapping for this packet. Signed-off-by: Florian Fainelli Signed-off-by: David S. Miller --- drivers/net/ethernet/broadcom/bcmsysport.c | 31 +++++++++++++--------- 1 file changed, 19 insertions(+), 12 deletions(-) diff --git a/drivers/net/ethernet/broadcom/bcmsysport.c b/drivers/net/ethernet/broadcom/bcmsysport.c index 6f4e18644bd4..d9b9170ed2fc 100644 --- a/drivers/net/ethernet/broadcom/bcmsysport.c +++ b/drivers/net/ethernet/broadcom/bcmsysport.c @@ -534,6 +534,25 @@ static unsigned int bcm_sysport_desc_rx(struct bcm_sysport_priv *priv, while ((processed < to_process) && (processed < budget)) { cb = &priv->rx_cbs[priv->rx_read_ptr]; skb = cb->skb; + + processed++; + priv->rx_read_ptr++; + + if (priv->rx_read_ptr == priv->num_rx_bds) + priv->rx_read_ptr = 0; + + /* We do not have a backing SKB, so we do not a corresponding + * DMA mapping for this incoming packet since + * bcm_sysport_rx_refill always either has both skb and mapping + * or none. + */ + if (unlikely(!skb)) { + netif_err(priv, rx_err, ndev, "out of memory!\n"); + ndev->stats.rx_dropped++; + ndev->stats.rx_errors++; + goto refill; + } + dma_unmap_single(kdev, dma_unmap_addr(cb, dma_addr), RX_BUF_LENGTH, DMA_FROM_DEVICE); @@ -543,23 +562,11 @@ static unsigned int bcm_sysport_desc_rx(struct bcm_sysport_priv *priv, status = (rsb->rx_status_len >> DESC_STATUS_SHIFT) & DESC_STATUS_MASK; - processed++; - priv->rx_read_ptr++; - if (priv->rx_read_ptr == priv->num_rx_bds) - priv->rx_read_ptr = 0; - netif_dbg(priv, rx_status, ndev, "p=%d, c=%d, rd_ptr=%d, len=%d, flag=0x%04x\n", p_index, priv->rx_c_index, priv->rx_read_ptr, len, status); - if (unlikely(!skb)) { - netif_err(priv, rx_err, ndev, "out of memory!\n"); - ndev->stats.rx_dropped++; - ndev->stats.rx_errors++; - goto refill; - } - if (unlikely(!(status & DESC_EOP) || !(status & DESC_SOP))) { netif_err(priv, rx_status, ndev, "fragmented packet!\n"); ndev->stats.rx_dropped++;