clockevents_program_event WARN_ON preventing boot.

[Dave Jones <davej@redhat.com>]

I have a machine that crashes instantly on boot up on Linus'
post-3.9 tree. (8c55f1463c1fd318d5e785f02b80bcc32176d342)

By booting with boot_delay=100, I was able to take a photo
and capture the top of the trace.  (For some reason, larger boot
delay parameters seem to make it take forever before printing
even a single character, which made this a pain to debug).

The WARN_ON it prints right before locking up is this in clockevents_program_event

208         if (unlikely(expires.tv64 < 0)) {
209                 WARN_ON_ONCE(1);
210                 return -ETIME;
211         }

booting with maxcpus=1 avoids the problem.

I'm still trying to get a complete stack trace, though it's painful
due to the above reason.

	Dave