Re: DoS attack against TCP services

["J. Hannken-Illjes" <hannken%eis.cs.tu-bs.de@localhost>]

On 28 Feb 2015, at 16:28, Christos Zoulas <christos%zoulas.com@localhost> wrote:

> On Feb 28, 11:37am, 6bone%6bone.informatik.uni-leipzig.de@localhost (6bone%6bone.informatik.uni-leipzig.de@localhost) wrote:
> -- Subject: Re: DoS attack against TCP services
> 
> | On Fri, 13 Feb 2015, Christos Zoulas wrote:
> | 
> | > I tried adding "show callout" to crash(8) but it is not useful because the
> | > pointers move too quickly. OTOH, next time this happens you can enter ddb
> | > on your machine and type "show callout" and see if that sheds any light
> | > to the expired and not fired callouts...
> | >
> | > christos
> | >
> | 
> | The problem occurred again. I have created a couple of screenshots. 
> | Unfortunately I can not interpret the output.
> | 
> | https://www.ipv6.uni-leipzig.de/callout_1.png
> | https://www.ipv6.uni-leipzig.de/callout_2.png
> | https://www.ipv6.uni-leipzig.de/callout_3.png
> | https://www.ipv6.uni-leipzig.de/callout_4.png
> | https://www.ipv6.uni-leipzig.de/callout_x.png
> | 
> | 
> | Thank your for your efforts
> 
> So all the timeouts have expired and are not firing anymore (negative times).
> This would indicate something broken with interrupts... Let me see where we
> can add some debugging...

Anyone holding "proc_lock"?  I had a similar problem with fstrans where
it was a deadlock with proc_lock preventing timer_intr() to succeed and
therefore all timers stopped working.

--
J. Hannken-Illjes - hannken%eis.cs.tu-bs.de@localhost - TU Braunschweig (Germany)