I am running 32bit Ubuntu 10.04. A lot of the times ksoftirqd/0 or ksoftirqd/1 start using up 100% CPU for no apparent reason, and I am forced to reboot my laptop.

Incidentally this also happens when I maximize my (youtube) videos on Chrome and Fireox, but once I un-maximize the videos the CPU usage goes down to the original levels.

Any ideas what it going on?

--- Addendum ---

dmesg produces a ~2000 line output. I searched for 'error' and 'warning' in the output, and here are the relevant lines (along with some headers):

[ 0.000000] Initializing cgroup subsys cpuset

[ 0.000000] Initializing cgroup subsys cpu

[ 0.000000] Linux version 2.6.32-21-generic (buildd@yellow) (gcc version 4.4.3 (Ubuntu 4.4.3-4ubuntu5) ) #32-Ubuntu SMP Fri Apr 16 08:09:38 UTC 2010 (Ubuntu 2.6.32-21.32-generic 2.6.32.11+drm33.2)

[ 0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz-2.6.32-21-generic root=UUID=157dcfda-acd6-4d1b-a6a8-ff9ccff61906 ro quiet splash

[ 0.000000] KERNEL supported cpus:

[ 0.000000] Intel GenuineIntel

[ 0.000000] AMD AuthenticAMD

[ 0.000000] Centaur CentaurHauls

[ 0.000000] BIOS-provided physical RAM map:

[ 24.775546] EXT3-fs warning: mounting fs with errors, running e2fsck is recommended

[44920.210518] ata1: SError: { PHYRdyChg CommWake 10B8B Dispar LinkSeq TrStaTrns }

[44920.210531] res 40/00:00:f0:4b:7f/00:00:18:00:00/40 Emask 0x10 (ATA bus error)

[58673.134623] chrome[20101]: segfault at 7f38bc4ad000 ip 00007f38be769ecc sp 00007fff24616850 error 4 in libpepflashplayer.so[7f38bdc08000+e55000]

[ 24.775546] EXT3-fs warning: mounting fs with errors, running e2fsck is recommended

[44920.210531] res 40/00:00:f0:4b:7f/00:00:18:00:00/40 Emask 0x10 (ATA bus error)