Re: latest -git: WARNING: at arch/x86/kernel/ipi.c:123 send_IPI_mask_bitmask+0xc3/0xe0()

[H. Peter Anvin]

Jeremy Fitzhardinge wrote:
> H. Peter Anvin wrote:
> > Well, smp_call_function_single already does all necessary locking; it
> > makes more sense for it to check that what it's about to call still
> > exists while inside the lock, instead of requiring the higher layers
> > to guarantee that cannot happen on it.  This is simply a matter of the
> > cost of checking at this point being quite low. 
>
> It does, already doesn't it?  Hm, smp_call_function_mask() ands the
> provided mask with the online mask, but it doesn't look like
> smp_call_function_single() does the equivalent.

It doesn't, and that's how this bug was introduced.  It's a trivial add 
(see test patch already posted) and should hardly matter in terms of 
execution time.

I'll write up a clean patch with all the error propagation tomorrow or 
Sunday.

	-hpa
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