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

H. Peter Anvin
2008-08-23T06:47:54Z

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