Re: [PATCH v1 1/2] ACPI: processor: Update cpuidle driver check in __acpi_processor_start()

[lihuisong (C)]

在 2025/9/19 19:17, Rafael J. Wysocki 写道:
> On Thu, Sep 18, 2025 at 11:10 PM Rafael J. Wysocki <rafael@xxxxxxxxxx> wrote:
> > From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> >
> > Commit 7a8c994cbb2d ("ACPI: processor: idle: Optimize ACPI idle
> > driver registration") moved the ACPI idle driver registration to
> > acpi_processor_driver_init() and acpi_processor_power_init() does
> > not register an idle driver any more, so the cpuidle driver check
> > in __acpi_processor_start() needs to be updated to avoid calling
> > acpi_processor_power_init() without a cpuidle driver (in which
> > case the registration of the cpuidle device in that function
> > would fail anyway).
> It's worse, it won't just fail, it'll lead to a NULL pointer
> dereference in __cpuidle_register_device().
>
> I'll update the changelog while applying the patch.
Yeah, thanks for fixing it.
Acked-by: lihuisong@xxxxxxxxxx
> > Fixes: 7a8c994cbb2d ("ACPI: processor: idle: Optimize ACPI idle driver registration")
> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> > ---
> >
> > Commit 7a8c994cbb2d is only in linux-next at this point.
> >
> > ---
> >   drivers/acpi/processor_driver.c |    2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > --- a/drivers/acpi/processor_driver.c
> > +++ b/drivers/acpi/processor_driver.c
> > @@ -166,7 +166,7 @@ static int __acpi_processor_start(struct
> >          if (result && !IS_ENABLED(CONFIG_ACPI_CPU_FREQ_PSS))
> >                  dev_dbg(&device->dev, "CPPC data invalid or not present\n");
> >
> > -       if (!cpuidle_get_driver() || cpuidle_get_driver() == &acpi_idle_driver)
> > +       if (cpuidle_get_driver() == &acpi_idle_driver)
> >                  acpi_processor_power_init(pr);
> >
> >          acpi_pss_perf_init(pr);