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net: systemport: check harder for out of memory conditions

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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 <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Florian Fainelli 2014-09-08 11:37:51 -07:00 committed by David S. Miller
parent 278d436a47
commit fe24ba082b
1 changed files with 19 additions and 12 deletions
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31
drivers/net/ethernet/broadcom/bcmsysport.c
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@ -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++;