Re: [PATCH v9 05/19] ACPI: processor: Fix memory leaks in error paths of processor_add()

Rafael J. Wysocki
2024-05-07T18:57:14Z

On Tue, Apr 30, 2024 at 4:27 PM Jonathan Cameron
<Jonathan.Cameron@huawei.com> wrote:
>
> If acpi_processor_get_info() returned an error, pr and the associated
> pr->throttling.shared_cpu_map were leaked.
>
> The unwind code was in the wrong order wrt to setup, relying on
> some unwind actions having no affect (clearing variables that were
> never set etc). That makes it harder to reason about so reorder
> and add appropriate labels to only undo what was actually set up
> in the first place.
>
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Thank you!

>
> ---
> v9: New patch in response to Gavin noticing a memory leak later in the
> series.
> ---
> drivers/acpi/acpi_processor.c | 15 ++++++++-------
> 1 file changed, 8 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
> index 5f062806ca40..16e36e55a560 100644
> --- a/drivers/acpi/acpi_processor.c
> +++ b/drivers/acpi/acpi_processor.c
> @@ -393,7 +393,7 @@ static int acpi_processor_add(struct acpi_device *device,
>
> result = acpi_processor_get_info(device);
> if (result) /* Processor is not physically present or unavailable */
> - return result;
> + goto err_clear_driver_data;
>
> BUG_ON(pr->id >= nr_cpu_ids);
>
> @@ -408,7 +408,7 @@ static int acpi_processor_add(struct acpi_device *device,
> "BIOS reported wrong ACPI id %d for the processor\n",
> pr->id);
> /* Give up, but do not abort the namespace scan. */
> - goto err;
> + goto err_clear_driver_data;
> }
> /*
> * processor_device_array is not cleared on errors to allow buggy BIOS
> @@ -420,12 +420,12 @@ static int acpi_processor_add(struct acpi_device *device,
> dev = get_cpu_device(pr->id);
> if (!dev) {
> result = -ENODEV;
> - goto err;
> + goto err_clear_per_cpu;
> }
>
> result = acpi_bind_one(dev, device);
> if (result)
> - goto err;
> + goto err_clear_per_cpu;
>
> pr->dev = dev;
>
> @@ -436,10 +436,11 @@ static int acpi_processor_add(struct acpi_device *device,
> dev_err(dev, "Processor driver could not be attached\n");
> acpi_unbind_one(dev);
>
> - err:
> - free_cpumask_var(pr->throttling.shared_cpu_map);
> - device->driver_data = NULL;
> + err_clear_per_cpu:
> per_cpu(processors, pr->id) = NULL;
> + err_clear_driver_data:
> + device->driver_data = NULL;
> + free_cpumask_var(pr->throttling.shared_cpu_map);
> err_free_pr:
> kfree(pr);
> return result;
> --
> 2.39.2
>