[CentOS] kernel bug ?

Hi,

I was using kernel-2.6.18-164.15.1 with no known issues. Then, I updated to:
Linux 2.6.18-194.17.1.el5 #1 SMP Wed Sep 29 12:50:31 EDT 2010 x86_64
x86_64 x86_64 GNU/Linux

I'm aware that there are later updates that patch couple more security bugs.

Here is an issue I run with 2.6.18-194.17.1 and am asking if anyone
hits that kernel bug.

Here are the symptoms:
1) kswapd1 running at 100%, there are not much paging
2) when i logged in, root can't kill -9 ANY processes
3) memory is used up, swap is probably only used up for couple hundred
MBs at most (Swap space has couple Gig available)

I saw in the logs:
kernel: INFO: task sadc:23936 blocked for more than 120 seconds.
kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables
this message.

Annoyingly, I failed to reproduce the issues.

I tried to reproduce it with the "stress" software package, using up
CPU, memory, etc. But I failed to reproduce those.
Reading later release of kernel did not mention this bug.

If anyone can contribute to what is happening here, that would be great.

Thanks