On 8/27/05, Eric Lemoine <[EMAIL PROTECTED]> wrote:
> On 8/26/05, Geoff Levand <[EMAIL PROTECTED]> wrote:
> > This fixes a major bug in the Sun GEM Ether
> > driver's netpoll implementation.  When both polled
> > and interrupt driven i/o are used simultaneously,
> > for example when using kgdb over Ether with active
> > NFS mounts, a condition easily arises where the bug
> > is hit.
> >
> > The problem is that gem_poll() expects an rx softnet_data
> > structure to have been allocated (via __netif_rx_schedule())
> > prior to its being called.  The existing gem driver code
> > uses gem_interrupt() to set things up for gem_poll(),
> > but unfortunately, gem_interrupt() doesn't know about
> > this, and so doesn't allocate the required structure
> > when it finds no bits set in the interrupt status
> > register.  gem_poll() then move on its way and tries to
> > delete the non-existent softnet_data structure.
> 
> I may be missing something here but I don't see how gem_poll() can
> move on its way if __netif_rx_schedule() hasen't been called. Wait...
> in netpoll.c:poll_napi()  because bit __LINK_STATE_RX_SCHED  is set,
> correct?
> 
> To me the bug is that __LINK_STATE_RX_SCHED can be set while
> __netif_rx_schedule() hasen't be called. Why don't fix it in the
> simplest way ? See attached patch (absolutely untested).

It doesn't even compile :-)

[new patch attached]

-- 
Eric

Attachment: sungem-netpoll-patch
Description: Binary data

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