From: Rask Ingemann Lambertsen <rask@sygehus.dk>
To: "David S. Miller" <davem@redhat.com>
Cc: jt@hpl.hp.com, jt@bougret.hpl.hp.com,
linux-kernel@vger.kernel.org, tsbogend@alpha.franken.de,
jgarzik@pobox.com, netdev@oss.sgi.com
Subject: Re: [BUG 2.6.0-test11] pcnet32 oops
Date: Tue, 9 Dec 2003 15:15:02 +0100 [thread overview]
Message-ID: <20031209151459.A1345@sygehus.dk> (raw)
In-Reply-To: <20031205165900.2920ea6a.davem@redhat.com>; from davem@redhat.com on Fri, Dec 05, 2003 at 04:59:00PM -0800
On Fri, Dec 05, 2003 at 04:59:00PM -0800, David S. Miller wrote:
> This is the classic case of doing disabling/enabling of software
> interrupts with hardware interrupts disabled, which is a bug.
>
> In this case pcnet32_set_multicast_list() is disabling hardware
> interrupts, and the packet freeing of pcnet32_purge_tx_ring()
> is what leads to the software interrupt disable/enable.
I think the root cause of this problem is that pcnet32_set_multicast_list()
dumps the entire TX ring on the floor (as a side effect of calling
pcnet32_restart()). I don't think dev->set_multicast_list() is supposed to
do that.
> However, I'm inclined to believe that we should change dev_kfree_skb_any()
> to fix this class of problems, by making it check for hardware interrupts
> being disabled as well as being in an interrupt.
I've been wondering about this too with the recent netpoll patches. Many
(including pcnet32) implement the poll controller simply as
disable_irq (dev->irq);
driver_interrupt_handler (dev->irq, dev, NULL);
enable_irq (dev->irq);
If the interrupt handler calls dev_kfree_skb_any(), could you then run into
this kind of problem? Or is it just if you call spin_lock_irq*() that you
have a problem?
--
Regards,
Rask Ingemann Lambertsen
next prev parent reply other threads:[~2003-12-09 14:15 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-12-05 23:45 [BUG 2.6.0-test11] pcnet32 oops Jean Tourrilhes
2003-12-06 0:59 ` David S. Miller
2003-12-09 14:15 ` Rask Ingemann Lambertsen [this message]
2003-12-10 8:30 ` David S. Miller
2003-12-10 8:32 ` David S. Miller
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