linux-kernel - Re: [PATCH] ACPI: processor: idle: Fix resource rollback in acpi_processor_power

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Message-ID: <CAJZ5v0gjkZ3a-BwgJxjUJbNwu5E_j9VUUHrR3M=a+KPTA-tZcA@mail.gmail.com>
Date: Wed, 2 Jul 2025 19:42:53 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Huisong Li <lihuisong@...wei.com>
Cc: rafael@...nel.org, lenb@...nel.org, linux-acpi@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linuxarm@...wei.com, 
	jonathan.cameron@...wei.com, zhanjie9@...ilicon.com, zhenglifeng1@...wei.com, 
	yubowen8@...wei.com, liuyonglong@...wei.com
Subject: Re: [PATCH] ACPI: processor: idle: Fix resource rollback in acpi_processor_power_init

On Thu, Jun 19, 2025 at 8:13 AM Huisong Li <lihuisong@...wei.com> 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@...wei.com>
> ---
>  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.

> +               }
>                 per_cpu(acpi_cpuidle_device, pr->id) = dev;
>
>                 acpi_processor_setup_cpuidle_dev(pr, dev);
> @@ -1402,14 +1404,22 @@ int acpi_processor_power_init(struct acpi_processor *pr)
>                  * must already be registered before registering device
>                  */
>                 retval = cpuidle_register_device(dev);
> -               if (retval) {
> -                       if (acpi_processor_registered == 0)
> -                               cpuidle_unregister_driver(&acpi_idle_driver);

Pretty much the same as here.

It would be good to clean up dev here though.

> -                       return retval;
> -               }
> +               if (retval)
> +                       goto free_cpuidle_device;
> +
>                 acpi_processor_registered++;
>         }
>         return 0;
> +
> +free_cpuidle_device:
> +       per_cpu(acpi_cpuidle_device, pr->id) = NULL;
> +       kfree(dev);
> +
> +unregister_driver:
> +       if (acpi_processor_registered == 0)
> +               cpuidle_unregister_driver(&acpi_idle_driver);
> +
> +       return retval;
>  }
>
>  int acpi_processor_power_exit(struct acpi_processor *pr)
> --
> 2.33.0
>