Re: BUG in pcnet32.c?

[Brian Murphy <brian@murphy.dk>]

Steven J. Hill wrote:

> Brian Murphy wrote:
>
> > In pcnet32.c where the driver writer sets up her receive buffers 
> > there is this line
> > lp->rx_dma_addr[i] = pci_map_single(lp->pci_dev, rx_skbuff->tail, 
> > rx_skbuff->len, PCI_DMA_FROMDEVICE);
> > the length value turns out to be 0 and crashes the running 
> > process,ifconfig.
> > Is making a map for a buffer of length 0 valid at all? If not what 
> > the hell is going on here.
> > I feel this should say PKT_BUF_SZ instead of rx_skbuff->len which is 
> > the length of skbuff which has been
> > allocated at this point in the code, this is line 986 in todays 
> > checkout.
> > Something is wrong in any case, any pointers?
> Excellent. So my new BUG code detected another bad network driver. 
> Your network
Not sure what you mean. I get the panic "Break instruction in kernel 
code" from do_bp
in traps.c. This seems like a strange "assertion" to me...

Anyway the attached patch fixes my problems, is anyone interested in 
reviewing it?
/Brian

Index: pcnet32.c
===================================================================
RCS file: /cvs/linux/drivers/net/pcnet32.c,v
retrieving revision 1.33.2.7
diff -u -r1.33.2.7 pcnet32.c
--- pcnet32.c   17 Nov 2003 01:07:38 -0000      1.33.2.7
+++ pcnet32.c   31 Mar 2004 20:31:01 -0000
@@ -983,7 +983,7 @@
        }
 
        if (lp->rx_dma_addr[i] == 0) 
-               lp->rx_dma_addr[i] = pci_map_single(lp->pci_dev, 
rx_skbuff->tail, rx_skbuff->len, PCI_DMA_FROMDEVICE);
+               lp->rx_dma_addr[i] = pci_map_single(lp->pci_dev, 
rx_skbuff->tail, PKT_BUF_SZ, PCI_DMA_FROMDEVICE);
        lp->rx_ring[i].base = (u32)le32_to_cpu(lp->rx_dma_addr[i]);
        lp->rx_ring[i].buf_length = le16_to_cpu(-PKT_BUF_SZ);
        lp->rx_ring[i].status = le16_to_cpu(0x8000);
@@ -1319,13 +1319,13 @@
                    if ((newskb = dev_alloc_skb (PKT_BUF_SZ))) {
                        skb_reserve (newskb, 2);
                        skb = lp->rx_skbuff[entry];
-                       pci_unmap_single(lp->pci_dev, lp->rx_dma_addr[entry], 
skb->len, PCI_DMA_FROMDEVICE);
+                       pci_unmap_single(lp->pci_dev, lp->rx_dma_addr[entry], 
PKT_BUF_SZ, PCI_DMA_FROMDEVICE);
                        skb_put (skb, pkt_len);
                        lp->rx_skbuff[entry] = newskb;
                        newskb->dev = dev;
                         lp->rx_dma_addr[entry] = 
                                pci_map_single(lp->pci_dev, newskb->tail,
-                                       newskb->len, PCI_DMA_FROMDEVICE);
+                                       PKT_BUF_SZ, PCI_DMA_FROMDEVICE);
                        lp->rx_ring[entry].base = 
le32_to_cpu(lp->rx_dma_addr[entry]);
                        rx_in_place = 1;
                    } else
@@ -1354,7 +1354,7 @@
                    skb_put(skb,pkt_len);       /* Make room */
                     pci_dma_sync_single(lp->pci_dev, 
                                        lp->rx_dma_addr[entry],
-                                       pkt_len,
+                                       PKT_BUF_SZ,
                                        PCI_DMA_FROMDEVICE);
                    eth_copy_and_sum(skb,
                                     (unsigned char 
*)(lp->rx_skbuff[entry]->tail),
@@ -1409,7 +1409,7 @@
     for (i = 0; i < RX_RING_SIZE; i++) {
        lp->rx_ring[i].status = 0;                          
        if (lp->rx_skbuff[i]) {
-            pci_unmap_single(lp->pci_dev, lp->rx_dma_addr[i], 
lp->rx_skbuff[i]->len, PCI_DMA_FROMDEVICE);
+            pci_unmap_single(lp->pci_dev, lp->rx_dma_addr[i], PKT_BUF_SZ, 
PCI_DMA_FROMDEVICE);
            dev_kfree_skb(lp->rx_skbuff[i]);
         }
        lp->rx_skbuff[i] = NULL;