On Mon, Jul 14, 2025 at 3:34 AM lihuisong (C) <lihuisong@xxxxxxxxxx> wrote:
>
>
> 在 2025/7/3 19:09, Rafael J. Wysocki 写道:
> > On Thu, Jul 3, 2025 at 8:23 AM lihuisong (C) <lihuisong@xxxxxxxxxx> wrote:
> >> Hi,
> >>
> >> Thanks for your review.
> >>
> >>
> >> 在 2025/7/3 1:42, Rafael J. Wysocki 写道:
> >>> On Thu, Jun 19, 2025 at 8:13 AM Huisong Li <lihuisong@xxxxxxxxxx> wrote:
> >>>> There are two resource rollback issues in acpi_processor_power_init:
> >>>> 1> Do not unregister acpi_idle_driver when do kzalloc failed.
> >>>> 2> Do not free cpuidle device memory when register cpuidle device failed.
> >>>>
> >>>> Signed-off-by: Huisong Li <lihuisong@xxxxxxxxxx>
> >>>> ---
> >>>> drivers/acpi/processor_idle.c | 24 +++++++++++++++++-------
> >>>> 1 file changed, 17 insertions(+), 7 deletions(-)
> >>>>
> >>>> diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
> >>>> index 2c2dc559e0f8..3548ab9dac9e 100644
> >>>> --- a/drivers/acpi/processor_idle.c
> >>>> +++ b/drivers/acpi/processor_idle.c
> >>>> @@ -1392,8 +1392,10 @@ int acpi_processor_power_init(struct acpi_processor *pr)
> >>>> }
> >>>>
> >>>> dev = kzalloc(sizeof(*dev), GFP_KERNEL);
> >>>> - if (!dev)
> >>>> - return -ENOMEM;
> >>>> + if (!dev) {
> >>>> + retval = -ENOMEM;
> >>>> + goto unregister_driver;
> >>> No, unregistering the driver here is pointless.
> >> I don't quite understand why here is pointless. Can you explain it?
> > When this function is run for another CPU, it will attempt to register
> > the driver again if it is unregistered here.
> Yeah, got it.
> So registering cpuidle also has a potential race issue here.
> >
> > Quite frankly, the driver should be registered before running this
> > function because it is a CPU hotplug callback and registering a
> > cpuidle driver from within it is quite questionable.
> >
> > Alternatively, it can be registered when all of the CPUs have been brought up.
> Agree with you.
> The reason why is that the initialization of acpi_idle_driver depands on
> the power management information of CPU.
> But the power management information of CPU is obtained in this callback.
> I have an idea.
> Because acpi_idle_driver is applied to all possiable CPUs. And use the
> power information of the first onlined CPU to initialize and register
> acpi_idle_driver, currently.
> So I think we can use this logic and dependency to extract a function to
> initialize and register acpi_idle_driver. And put this function to
> acpi_processor_driver_init().
> I tested it is ok.
> What do you think about this?
This is one of the options I mentioned above, isn't it?
