Re: WARNING: smp_call_function_single() and smp_call_function_mask()

[Tomas Carnecky]

Arjan van de Ven wrote:
> On Sun, 02 Dec 2007 09:43:39 +0100
> Tomas Carnecky <tom@xxxxxxxxxxxxx> wrote:
> 
>> WARNING: at arch/x86/kernel/smp_64.c:427 smp_call_function_single()
>> WARNING: at arch/x86/kernel/smp_64.c:397 smp_call_function_mask()
>>
>> dmesg and config attached.
>>
>> I'm getting about three of each at boot. I'm running:
>> commit e1cca7e8d484390169777b423a7fe46c7021fec1
>> Date:   Thu Nov 29 16:25:29 2007 -0800
>> which is the latest git as of yesterday plus a one (unrelated) debug
>> statement patch in usb uhci.
>>
>> There was a similar bug report after 2.6.23-rc8-mm was released.
>> Though there seems to be a fundamental problem with how people use
>> smp_call_function*() [1]. And this can just as well be another
>> incarnation of it.
>>
>> Is that easy enough to fix or do I need to bisect (it didn't happen in
>> 2.6.24-rc3)?
>>
> 
> this appears to be a bug in the acpi code, to be exact in
> processor_throttling.c file, function
> acpi_processor_set_throttling_ptc(); it disables interrupts and then
> appears to do a cross-cpu IPI to set the state. Well... we can't do
> that due to deadlock reasons (you can't do IPI's with interrupts off or
> you can get a very nice deadlock with the cpu that you IPI trying to
> do the same thing to you).
> 

I updated the kernel today (to 1a2edea9aff48...) and the warnings are gone.

tom
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