When I suspend or hibernate my laptop, the
Ksoftirqd/1 process runs on 100% continuously.
I have to reboot or shutdown my laptop then.
This happens in Ubuntu 10.04, 10.10, 11.04 and all variants.
The problem is very probable with the driver of your network card: Google reveals a lot of similar problems elsewhere: like in Finnish this.
So simply disable the unnecessary drivers or update old ones.