Re: Hardware for Debian-68k
On Thu, 15 Mar 2007, Michael Schmitz wrote:
> > > and the transmit timeout handling, but the driver has been largely
> > > rewritten. I'll have to look at it some more to see what might be
> > > used.
> >
> > I think that the bug that bit Wouter's 950 was a race between the tx
> > code and the interrupt handler (though it was a while ago that I
> > looked at this). If so, the 2.6 version could need a complete
> > back-port, since both algorithms changed significantly to get
> > zero-copy in the present version (and to adopt the DMA API, which
> > isn't in 2.2). There is probably a quicker fix.
>
> If you could remember what the nature of the race was, I could perhaps
> find a way to prevent it. Note that the transmit function now only stops
> the queue if the ring is full; that may be important.
When I look at the 2.2 code now, I'm immediately suspicious of the
interaction between sonic_send_packet() and sonic_interrupt(), with
respect to lp->tx_full, lp->cur_tx, lp->dirty_tx and lp->tx_laddr[].
Reason being, there is no mutual exclusion to prevent interrupt handler
from interfering with the other routine.
Still, it isn't clear to me how this leads to "Warning: kfree_skb passed
an skb still on a list (from 000e4416)." I don't know how these lists
work. Does the address 000e4416 tell you anything?
-f
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