On Tuesday, February 28, 2012, Paul E. McKenney wrote:
> On Tue, Feb 28, 2012 at 03:19:43PM +0800, Yong Zhang wrote:
> > On Thu, Feb 23, 2012 at 12:58:05PM -0800, Paul E. McKenney wrote:
> > > The acpi_processor_cst_has_changed() function is invoked from a
> > > CPU_ONLINE or CPU_DEAD function, which might well execute on CPU 0
> > > even though the CPU being hotplugged is some other CPU. In addition,
> > > acpi_processor_cst_has_changed() invokes smp_processor_id() without
> > > protection, resulting in splats when onlining CPUs.
> > >
> > > This commit therefore changes the smp_processor_id() to pr->id, as is
> > > used elsewhere in the code, for example, in acpi_processor_add().
> > >
> > > This works for me, but I don't claim to understand ACPI.
> > >
> > > Signed-off-by: Paul E. McKenney <paul.mckenney@xxxxxxxxxx>
> >
> > Got the same warning.
> > And the patch works on my side.
> >
> > Tested-by: Yong Zhang <yong.zhang0@xxxxxxxxx>
>
> Thank you, I have added your Tested-by (and Srivatsa's Reviewed-by,
> for that matter).
>
> Any takers for this, or should I just push it up the -tip tree?
I think this patch is for Len, either through ACPI, or through the idle tree.
Len?
Anyway:
Acked-by: Rafael J. Wysocki <rjw@xxxxxxx>
Thanks,
Rafael
> > > diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
> > > index 0e8e2de..9e57b06 100644
> > > --- a/drivers/acpi/processor_idle.c
> > > +++ b/drivers/acpi/processor_idle.c
> > > @@ -1159,8 +1159,7 @@ int acpi_processor_cst_has_changed(struct acpi_processor *pr)
> > > * to make the code that updates C-States be called once.
> > > */
> > >
> > > - if (smp_processor_id() == 0 &&
> > > - cpuidle_get_driver() == &acpi_idle_driver) {
> > > + if (pr->id == 0 && cpuidle_get_driver() == &acpi_idle_driver) {
> > >
> > > cpuidle_pause_and_lock();
> > > /* Protect against cpu-hotplug */
> > >
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