From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Thu, 26 Feb 2009 19:56:04 +0800

On Thu, Feb 26, 2009 at 10:56:16AM +0000, Jarek Poplawski wrote:

quoted

netconsole. It's a known issue, btw.

I see.  So the problem in this case appears to be that we're
processing incoming packets in netpoll_poll.  So the obvious
question can we just not do that since all we need to do is
transmit packets?

netpoll supports receiving packets and has a trap handler to eat them
to avoid packets it is interested in going into the real stack.
(netpoll_receive_skb, netpoll_rx_skb, etc.)

I'm pretty sure this has been discussed before. :-)

If I'm not mistaken, we only see this with certain drivers, and the
issue therefore likely has to do with how such drivers implement their
poll handler.

If you do your ->poll_controller() handler without taking IRQ locks,
you're fine.  Or something like that...