Exception in kernel mode

[Charles Krinke]

I ran a couple of more tests and the system did not Oops in the
timer_interupt except for the first test this morning. The last two
times, the NIP was 

Oops: Exception in kernel mode, sig: 4 [#1]
PREEMPT
NIP: C002CE68 LR: C002CEC8 CTR: 00003B25
REGS: c3119a00 TRAP: 0700   Not tainted  (2.6.17.11)
MSR: 00081032 <ME,IR,DR>  CR: 88022484  XER: 00000000
TASK = c3ecd870[920] 'tar' THREAD: c3118000

And

Oops: Exception in kernel mode, sig: 4 [#1]
PREEMPT
NIP: C00DEE18 LR: C00DEDD8 CTR: 00000000
REGS: c299dbc0 TRAP: 0700   Not tainted  (2.6.17.11)
MSR: 00081032 <ME,IR,DR>  CR: 84022488  XER: 20000000
TASK = c3e2b7d0[925] 'tar' THREAD: c299c000

For comparision, this is the original one from this morning

Oops: Exception in kernel mode, sig: 4 [#1]
PREEMPT
NIP: 00000900 LR: C00E579C CTR: 00003A55
REGS: c37f3b00 TRAP: 0700   Not tainted  (2.6.17.11)
MSR: 00081000 <ME>  CR: 24022484  XER: 00000000
TASK = c3eaf810[940] 'tar' THREAD: c37f2000

I have to conclude this is not necessarily a timer_interrupt problem.
Also, commenting out the innards of the timer_interrupt causes the
kernel to hang in its boot right after the message

Memory: xxxK available

So a properly functioning timer_interrupt is essential to the the kernel
booting. 

But, ... At this point, I really don't know which way to jump.

Charles