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Message-ID: <4A853572.70209@gmail.com>
Date: Fri, 14 Aug 2009 11:59:14 +0200
From: Roel Kluin <roel.kluin@...il.com>
To: David Miller <davem@...emloft.net>
CC: netdev@...r.kernel.org, akpm@...ux-foundation.org
Subject: Re: [PATCH] yellowfin: Fix buffer underrun after dev_alloc_skb()
failure
When dev_alloc_skb fails in the first iteration, a buffer underrun occurs.
Signed-off-by: Roel Kluin <roel.kluin@...il.com>
---
> I think this is a case where this code is going to need to
> be majorly reworked so that you can pass error status up
> to the caller when this allocation failure happens, and
> the caller can properly act upon it.
>
> Just silently returning when no RX ring has been allocated,
> and the TX ring hasn't been setup at all, is going to be
> worse than the array overrun you're supposedly fixing.
I think it should be something like this. Should yellowfin_open()
do more than just passing the yellowfin_init_ring() error?
diff --git a/drivers/net/yellowfin.c b/drivers/net/yellowfin.c
index a075801..ee35b11 100644
--- a/drivers/net/yellowfin.c
+++ b/drivers/net/yellowfin.c
@@ -346,7 +346,7 @@ static int netdev_ioctl(struct net_device *dev, struct ifreq *rq, int cmd);
static int yellowfin_open(struct net_device *dev);
static void yellowfin_timer(unsigned long data);
static void yellowfin_tx_timeout(struct net_device *dev);
-static void yellowfin_init_ring(struct net_device *dev);
+static int yellowfin_init_ring(struct net_device *dev);
static int yellowfin_start_xmit(struct sk_buff *skb, struct net_device *dev);
static irqreturn_t yellowfin_interrupt(int irq, void *dev_instance);
static int yellowfin_rx(struct net_device *dev);
@@ -573,19 +573,22 @@ static int yellowfin_open(struct net_device *dev)
{
struct yellowfin_private *yp = netdev_priv(dev);
void __iomem *ioaddr = yp->base;
- int i;
+ int i, ret;
/* Reset the chip. */
iowrite32(0x80000000, ioaddr + DMACtrl);
- i = request_irq(dev->irq, &yellowfin_interrupt, IRQF_SHARED, dev->name, dev);
- if (i) return i;
+ ret = request_irq(dev->irq, &yellowfin_interrupt, IRQF_SHARED, dev->name, dev);
+ if (ret)
+ return ret;
if (yellowfin_debug > 1)
printk(KERN_DEBUG "%s: yellowfin_open() irq %d.\n",
dev->name, dev->irq);
- yellowfin_init_ring(dev);
+ ret = yellowfin_init_ring(dev);
+ if (ret)
+ return ret;
iowrite32(yp->rx_ring_dma, ioaddr + RxPtr);
iowrite32(yp->tx_ring_dma, ioaddr + TxPtr);
@@ -725,10 +728,10 @@ static void yellowfin_tx_timeout(struct net_device *dev)
}
/* Initialize the Rx and Tx rings, along with various 'dev' bits. */
-static void yellowfin_init_ring(struct net_device *dev)
+static int yellowfin_init_ring(struct net_device *dev)
{
struct yellowfin_private *yp = netdev_priv(dev);
- int i;
+ int i, j;
yp->tx_full = 0;
yp->cur_rx = yp->cur_tx = 0;
@@ -753,6 +756,11 @@ static void yellowfin_init_ring(struct net_device *dev)
yp->rx_ring[i].addr = cpu_to_le32(pci_map_single(yp->pci_dev,
skb->data, yp->rx_buf_sz, PCI_DMA_FROMDEVICE));
}
+ if (i != RX_RING_SIZE) {
+ for (j = 0; j < i; j++)
+ dev_kfree_skb(yp->rx_skbuff[j]);
+ return -ENOMEM;
+ }
yp->rx_ring[i-1].dbdma_cmd = cpu_to_le32(CMD_STOP);
yp->dirty_rx = (unsigned int)(i - RX_RING_SIZE);
@@ -769,8 +777,6 @@ static void yellowfin_init_ring(struct net_device *dev)
yp->tx_ring[--i].dbdma_cmd = cpu_to_le32(CMD_STOP | BRANCH_ALWAYS);
#else
{
- int j;
-
/* Tx ring needs a pair of descriptors, the second for the status. */
for (i = 0; i < TX_RING_SIZE; i++) {
j = 2*i;
@@ -805,7 +811,7 @@ static void yellowfin_init_ring(struct net_device *dev)
}
#endif
yp->tx_tail_desc = &yp->tx_status[0];
- return;
+ return 0;
}
static int yellowfin_start_xmit(struct sk_buff *skb, struct net_device *dev)
--
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