From: Dave Hansen <haveblue@us.ibm.com>

Hmmm.  This is looking like fallout from the massive wli-bomb.  Here's
the loop that controls the cpu booting, before and after cpumask_t:

-	for (bit = 0; kicked < NR_CPUS && bit < BITS_PER_LONG; bit++)
+	for (bit = 0; kicked < NR_CPUS && bit < MAX_APICS; bit++)
		apicid = cpu_present_to_apicid(bit);

"kicked" only gets incremented for CPUs that were successfully booted,
so it doesn't help terminate the loop much.  MAX_APICS is 256 on summit,
which is *MUCH* bigger than BITS_PER_LONG.
cpu_2_logical_apicid[NR_CPUS] which is referenced from
cpu_present_to_apicid() is getting referenced up to MAX_APICs, which is
bigger than NR_CPUS.  Overflow.  Bang.  garbage != BAD_APICID :)