Check with "top" what process got the near 100% CPU, it is impossible that is no processes gain cpu time.
None :S I don't get it...Again, if you look the CPU usage is sitting at over 90% but the processes only add up to 12% CPU utilization...
top - 18:47:14 up 8 days, 3:27, 1 user, load average: 2.11, 1.85, 1.60
Tasks: 59 total, 3 running, 56 sleeping, 0 stopped, 0 zombie
Cpu(s): 2.7%us, 86.3%sy, 0.0%ni, 0.0%id, 10.7%wa, 0.3%hi, 0.0%si, 0.0%st
Mem: 254908k total, 250876k used, 4032k free, 31364k buffers
Swap: 514072k total, 72k used, 514000k free, 152668k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ TIME COMMAND
26168 root 25 0 2096 560 432 R 10.3 0.2 1:13.49 1:13 rrdfix.sh
26167 root 18 0 1532 512 412 S 0.7 0.2 0:05.95 0:05 find
1 root 16 0 1512 568 480 S 0.0 0.2 0:18.65 0:18 init
2 root 11 -5 0 0 0 S 0.0 0.0 0:00.01 0:00 kthreadd
3 root RT -5 0 0 0 S 0.0 0.0 0:00.00 0:00 migration/0
4 root 34 19 0 0 0 S 0.0 0.0 0:09.47 0:09 ksoftirqd/0
5 root RT -5 0 0 0 S 0.0 0.0 0:00.00 0:00 watchdog/0
6 root 10 -5 0 0 0 S 0.0 0.0 0:00.97 0:00 events/0
7 root 11 -5 0 0 0 S 0.0 0.0 0:00.10 0:00 khelper
42 root 10 -5 0 0 0 S 0.0 0.0 0:16.74 0:16 kblockd/0
43 root 20 -5 0 0 0 S 0.0 0.0 0:00.00 0:00 kacpid
44 root 20 -5 0 0 0 S 0.0 0.0 0:00.00 0:00 kacpi_notify
210 root 16 -5 0 0 0 S 0.0 0.0 0:00.00 0:00 cqueue/0
211 root 16 -5 0 0 0 S 0.0 0.0 0:00.00 0:00 ksuspend_usb
214 root 16 -5 0 0 0 S 0.0 0.0 0:00.00 0:00 khubd
216 root 11 -5 0 0 0 S 0.0 0.0 0:00.00 0:00 kseriod
237 root 20 0 0 0 0 S 0.0 0.0 0:00.00 0:00 pdflush