From: David Mosberger <davidm@napali.hpl.hp.com>

interrupts_open() can easily try to kmalloc() more memory than
supported by kmalloc.  E.g., with 16KB page size and NR_CPUS==64, it
would try to allocate 147456 bytes.

The workaround below is to allocate 4KB per 8 CPUs.  Not really a
solution, but the fundamental problem is that /proc/interrupts
shouldn't use a fixed buffer size in the first place.  I suppose
another solution would be to use vmalloc() instead.  It all feels like
bandaids though.