On Friday, 6-Jul-2007 at 7:17 +0200, Thomas Gleixner wrote:
I think it's reproducible at will when CONFIG_BUG is enabled, because the
WARN_ON() on line 546 of arch/i386/kernel/smp.c fires in smp_call_function(),
causing lots of console output. By the time on_each_cpu() later reenables
interrupts, another clock interrupt is pending, and (I think) causes a
self-deadlock on the xtime_lock in vmi_account_real_cycles().
That's my (unproven) theory, anyway. :)
At any rate, I reproduced it twice in two tries on stock 2.6.21.