Re: [PATCH] drivers/acpi/processor_driver.c: add missing kfree

From: Srivatsa S. Bhat
Date: Thu Mar 15 2012 - 05:37:02 EST


On 03/15/2012 02:02 PM, Julia Lawall wrote:

> From: Julia Lawall <Julia.Lawall@xxxxxxx>
>
> The function acpi_processor_add is stored in the ops.add field of a
> acpi_driver structure. This function is then called in
> acpi_bus_driver_init. On failure, this function clears the field
> device->driver_data, but does not free its contents. Thus the free has to
> be done by the add function. In acpi_processor_add, the corresponding
> value is pr. This value is currently freed on failure before storing it in
> device->driver_data, but not after. This free is added in the error
> handling code at the end of the function. The per_cpu variable
> processors is also cleared so that it does not refer to a dangling pointer.
>
> Signed-off-by: Julia Lawall <Julia.Lawall@xxxxxxx>
>


See a minor nitpick below.. Other than that, everything looks great!

Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@xxxxxxxxxxxxxxxxxx>

> ---

> drivers/acpi/processor_driver.c | 13 +++++++++----
> 1 file changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c
> index 2801b41..98c3648 100644
> --- a/drivers/acpi/processor_driver.c
> +++ b/drivers/acpi/processor_driver.c
> @@ -536,8 +536,8 @@ static int __cpuinit acpi_processor_add(struct acpi_device *device)
> return -ENOMEM;
>
> if (!zalloc_cpumask_var(&pr->throttling.shared_cpu_map, GFP_KERNEL)) {
> - kfree(pr);
> - return -ENOMEM;
> + result = -ENOMEM;
> + goto err_free_pr;
> }
>
> pr->handle = device->handle;
> @@ -577,7 +577,7 @@ static int __cpuinit acpi_processor_add(struct acpi_device *device)
> dev = get_cpu_device(pr->id);
> if (sysfs_create_link(&device->dev.kobj, &dev->kobj, "sysdev")) {
> result = -EFAULT;
> - goto err_free_cpumask;
> + goto err_clear_processor;
> }
>
> /*
> @@ -595,9 +595,14 @@ static int __cpuinit acpi_processor_add(struct acpi_device *device)
>
> err_remove_sysfs:
> sysfs_remove_link(&device->dev.kobj, "sysdev");
> +err_clear_processor:
> + /* processor_device_array is not cleared to allow checks for buggy
> + BIOSes */


Multi-line comments in the kernel are generally written like:

/*
* blah blah blah
* blah blah ....
*/

> + per_cpu(processors, pr->id) = NULL;
> err_free_cpumask:
> free_cpumask_var(pr->throttling.shared_cpu_map);
> -
> +err_free_pr:
> + kfree(pr);
> return result;
> }
>






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