From dc5a144991ba803bc8afded105c9db1dea0e57ab Mon Sep 17 00:00:00 2001 From: Neil Horman Date: Thu, 26 Apr 2007 13:47:36 -0400 Subject: sis900: Allocate rx replacement buffer before rx operation Just found a hole in my last patch. It was reported to me that shortly after we integrated this patch. The report was of an oops that took place inside of netif_rx when using the sis900 driver. Looking at my origional patch I noted that there was a spot between the new skb_alloc and the refill_rx_ring label where skb got reassigned to the pointer currently held in the rx_ring for the purposes of receiveing the frame. The result of this is however that the buffer that gets passed to netif_rx (if it is called), then gets placed right back into the rx_ring. So if you receive frames fast enough the skb being processed by the network stack can get corrupted. The reporter is testing out the fix I've written for this below (I'm not near my hardware at the moment to test myself), but I wanted to post it for review ASAP. I'll post test results when I hear them, but I think this is a pretty straightforward fix. It just uses a separate pointer to do the rx operation, so that we don't improperly reassign the pointer that we use to refill the rx ring. Signed-off-by: Neil Horman Signed-off-by: Jeff Garzik --- drivers/net/sis900.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/net/sis900.c b/drivers/net/sis900.c index dea0126723da..2cb2e156c758 100644 --- a/drivers/net/sis900.c +++ b/drivers/net/sis900.c @@ -1753,6 +1753,7 @@ static int sis900_rx(struct net_device *net_dev) sis_priv->rx_ring[entry].cmdsts = RX_BUF_SIZE; } else { struct sk_buff * skb; + struct sk_buff * rx_skb; pci_unmap_single(sis_priv->pci_dev, sis_priv->rx_ring[entry].bufptr, RX_BUF_SIZE, @@ -1786,10 +1787,10 @@ static int sis900_rx(struct net_device *net_dev) } /* give the socket buffer to upper layers */ - skb = sis_priv->rx_skbuff[entry]; - skb_put(skb, rx_size); - skb->protocol = eth_type_trans(skb, net_dev); - netif_rx(skb); + rx_skb = sis_priv->rx_skbuff[entry]; + skb_put(rx_skb, rx_size); + rx_skb->protocol = eth_type_trans(rx_skb, net_dev); + netif_rx(rx_skb); /* some network statistics */ if ((rx_status & BCAST) == MCAST) -- cgit v1.2.3