Re: BUG in pcnet32.c?

["Steven J. Hill" <sjhill@realitydiluted.com>]

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
driver is broken and it needs fixed. I will refer you to these posts between
Jeff Garzik and myself when I found a similar issue on the 'natsemi.c' driver.
Mapping a PCI address with length zero is a BUG, period. You length should
be the maximum RX buffer length + 2. You will see from the patches in the
messages below that this is for IP header alignment. Good luck and please let
use know how it turns out.

-Steve

http://lkml.org/lkml/2004/3/16/218
http://lkml.org/lkml/2004/3/16/244