Comment 8 for bug 1100202

@henrix and @timg-tpi I think that the fix only prevents the warning, but it only silence the problem.

I am not a kernel hacker, and probably I am wrong with this, but searching in google,
the mask for IPI seems important to be skipped without consecuences in future.

It is used for x86/apic. APIC (Advanced Programmable Interrupt Controller) provides
the interrupt handling with multiprocessor support and more IRQs.

As far I read, there are Non-Maskable Interrupts (NMI, http://en.wikipedia.org/wiki/Non-maskable_interrupt), i.e, no mask with
the interrupt and it shouldn't be ignored. So if the kernel skip the mask, I guess that it always process the interrupt
even if it is not needed process that exact interrupt. That could be a perfomance penalty in some uses. Also, a no mask seems to be used only with critical cases or as debugging case for faulty code.

Like I said, I am not kernel developer, likely I am saying a dumbness, but it would nice if someone confirm that it is all ok
skipping the mask for APIC. I am running lastest kernel in raring and since I hit this bug I cannot connect my ethernet card to internet (probably because the interrupt it is not processed properly).