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Date: Thu, 24 Dec 2009 19:06:30 -0500 From: Daniel Hazelton <dhazelton@...er.net> To: Michael Breuer <mbreuer@...jas.com> Cc: Stephen Hemminger <shemminger@...tta.com>, Berck Nash <flyboy@...il.com>, Andrew Morton <akpm@...ux-foundation.org>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, netdev@...r.kernel.org Subject: Re: sky2 panic in 2.6.32.1 under load On Thursday 24 December 2009 05:42:08 pm Michael Breuer wrote: > On 12/24/2009 5:21 PM, Stephen Hemminger wrote: > > On Thu, 24 Dec 2009 11:28:57 -0500 > > > > Daniel Hazelton<dhazelton@...er.net> wrote: > >> On Thursday 24 December 2009 11:03:56 am Berck Nash wrote: > >>> Andrew Morton wrote: > >>>> On Mon, 21 Dec 2009 16:52:10 -0700 "Berck E. Nash"<flyboy@...il.com> > >> > >> wrote: > >>>>> Since 2.6.32, I've been getting kernel panics under heavy network > >>>>> load (bittorrent usage). > >>>> > >>>> Let's cc the right list and developer. > >>>> > >>>> This is a 2.6.31->2.6.32 regression? > >>> > >>> I believe so. Since it's intermittent and difficult to reproduce, it's > >>> possible (but unlikely) that I simply never triggered it under 2.6.31. > >> > >> This is far from new. I have seen this under 2.6.27 when at least one > >> botnet has been pointed at a server of mine and told to gain access. It > >> has happened four times in the last six to eight months - and I have no > >> easy way to capture the logs. But the oops that was posted looks very, > >> very similar to what I've seen. > >> > >> It's always an allocation error in the transmit path that leads to the > >> panic. Because this is a production machine that I do not have a way to > >> take down and do testing with I've not reported the problem before. > > > > Even though I wrote/maintain the sky driver, I don't work for SysKonnect, > > and only have access to a limited set of information: > > the technical manuals (under NDA), and the vendor sk98lin driver. The > > sky2 driver imitates the receiver timeout of the sk98lin driver; other > > people have told me that the FIFO hardware implementation is buggy and > > when it gets full, it gets stuck. Probably the equivalent of a software > > FIFO where the developer forgets to reserve a slot so that head == tail > > can mean both empty and full! > > > > The workaround with a timer is prone to errors when traffic keeps going, > > also the vendor doesn't really provide clear instructions on how to > > unlock it. I do not have access to the hardware errata describing the > > problem. If I did a more minimal solution would be possible. > > > > The easiest advice is avoid sky2 chips with FIFO for any heavy traffic, > > the next advice is make sure receive flow control is enabled so that > > receiver doesn't get overrun. If tx timeouts are an issue use a rate > > limiter like TBF. Do not use the chip with 10 or 100 mbit since the > > transmitter is more prone to get overrun. > > For this particular issue, I'm only seeing problems when running at 1000 > mbit. 100 appears stable. > Not here - it is crashing under 100. I do have a different NIC available for that system and will likely switch to it when I have a chance to work on upgrading the install there. The reason I am using the Sky NIC on that system is because there are, apparently, two different NIC's on the board itself - an nForce one and a Sky2 one... DRH -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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