Subject: Re: fxp card causing freeze on netbsd 2?
To: Steve Woodford <>
From: Stuart Brooks <>
List: tech-kern
Date: 04/18/2005 11:20:03
> On Monday 18 April 2005 08:21, Stuart Brooks wrote:
> > I have a Netbsd 2 machine with an Intel SB82558B chipset network
> > which has frozen a couple of times. The interesting thing is that
> > network card is going mad but everything else has locked up.
> I've also seen this with fxp(4). In my case it happens when the kernel
> stops servicing Rx interrupts (while in ddb, for example). When the
> fills the remaining Rx buffers it starts flooding the wire with
> flow-control packets (as evidenced by your tcpdump) which can swamp
> upstream switch to the point where all other traffic on the switch is
> blocked (I've observed this behaviour on several flavours of switch).
> An easy way to provoke this bug is to drop into ddb, then ping the
> machine until the fxp's Rx buffers are exhausted.

So it would seem this may just be a symptom rather than the cause of my
problems (ie. kernel or hardwared lockup). I generally have my system at
the X terminal which means that when it freezes I can't see the kernel
printouts:( Ctr-Alt-Esc didn't do anything either.

Thanks for the help,