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Subject: Re: [ACPI] ACPI using smp_processor_id in preemptible code
From: Li Shaohua <shaohua.li@intel.com>
To: Pavel Machek <pavel@ucw.cz>
Cc: ACPI mailing list <acpi-devel@lists.sourceforge.net>,
       kernel list <linux-kernel@vger.kernel.org>
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On Mon, 2005-01-10 at 17:55, Pavel Machek wrote:
> > >I enabled CPU hotplug and preemptible debugging... now I get...
> > >
> > >BUG: using smp_processor_id() in preemptible [00000001] code:
> > >swapper/0
> > >caller is acpi_processor_idle+0xb/0x235
> > > [<c020ba28>] smp_processor_id+0xa8/0xc0
> > > [<c02338ce>] acpi_processor_idle+0xb/0x235
> > > [<c02338c3>] acpi_processor_idle+0x0/0x235
> > > [<c02338ce>] acpi_processor_idle+0xb/0x235
> > > [<c02338c3>] acpi_processor_idle+0x0/0x235
> > > [<c02338c3>] acpi_processor_idle+0x0/0x235
> > > [<c02338c3>] acpi_processor_idle+0x0/0x235
> > > [<c0101115>] cpu_idle+0x75/0x110
> > > [<c04f5988>] start_kernel+0x158/0x180
> > > [<c04f5390>] unknown_bootoption+0x0/0x1e0
> > It doesn't trouble to me. It's in idle thread.
> 
> You mean it does not happen to you? On my machine it fills logs very
> quickly...
What I mean is idle thread can't be migrated so this doesn't impact the
correctness. I guess the preemptible debugging can't recognise such
situation.

Thanks,
Shaohua