Repeating kernel panic within dummynet

[Vlad Galu]

On Jul 11, 2011, at 1:51 PM, Eugene Grosbein wrote:

> 11.07.2011 18:45, Vlad Galu пишет:
>> 
>> On Jul 11, 2011, at 1:42 PM, Eugene Grosbein wrote:
>> 
>>> Hi!
>>> 
>>> My FreeBSD 8.2/amd64 routers use dummynet heavily
>>> and keep panic with the *same* KDB backtrace:
>>> 
>>> dummynet: bad switch -256!
> 
> Forgot to mention that I use io_fast dummynet mode
> and have increased pipe lengths:
> 
> net.inet.ip.dummynet.pipe_slot_limit=1000
> net.inet.ip.dummynet.io_fast=1
> 
> Distinct pipes do really use long lengths.
> 
>>> Sadly, I cannot add options INVARIANTS to the kernel because it makes my mpd-based
>>> routers to panic very often (every 2-3 hours) due to famous 'dangling pointer'
>>> problem - PPPoE user disconnects, its ngXXX interface got removed, then its traffic
>>> goes out various system queues (netisr, dummynet etc.) and another kind of panic
>>> occurs due to INVARIANTS' references to non-existent ifp.
>> 
>> Hi Eugene,
>> If your ISR threads aren't already bound to CPUs, you can bind them and try using INVARIANTS.
> 
> Please explain how to bind them. I have 4-core boxes with 4 NICs grouped to 2 laggs,
> one lagg(4) for uplink and another one for downlink.
> 

net.isr.bindthreads=1

I'm not sure how and if that would help your particular setup, but it did so in Adrian Minta's recent netgraph/mpd experiments. According to an off-list chat I had with him, the machine would panic unless the ISRs were bound.

> Eugene Grosbein