Re: boot panic regression introduced in 3.5-rc7

John Stultz
2012-07-30T21:01:20Z

> [ 2.971092] Hardware name: PowerEdge M605
> [ 2.971092] Modules linked in:
Looking at the dmesg:

[ 0.000000] Extended CMOS year: 8200

I'm working with Prarit to try to debug the issue on the affected
machine. He noticed part of the problem is that the offs_real was set
to 0x7FFFFFFFFFFFFFFF, which is the same as KTIME_MAX.

I suspect from the dmesg above we're getting bad data from the CMOS
clock, and that's then causing an overflow converting to a ktime_t
(64bits of nanoseconds can only hold ~584 years).

I've still not quite narrowed down why this hasn't bit you earlier,
since the same wall_to_monotonic -> ktime conversion was done in
retrigger_next_event before the change. Maybe something called
settimeofday(), fixing crazy time value before you switched to highres mode?

Once I sort out this last question, I'll try to see where we can add
some sanity checking for this sort of thing.

thanks
-john