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hwmon: (acpi_power_meter) clean up freeing code

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This code works okay but Smatch flagged it as a double free.  I've
changed three things to make it more clear.  1)  Remove the call to
free_capabilities() in acpi_power_meter_add().  This call is a no-op
because the capabilities have not been allocated yet.  2)  Set "*str" to
NULL in free_capabilities() so that way the function can be called twice
in a row without leading to a double free.  3)  Call free_capabilities()
in read_capabilities() instead of open coding the free.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20201007075148.GB2529578@mwanda
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Dan Carpenter 2020-10-07 10:51:48 +03:00 committed by Guenter Roeck
parent bce776f100
commit 96eca8c97f
1 changed files with 4 additions and 5 deletions
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9
drivers/hwmon/acpi_power_meter.c
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@ -725,8 +725,10 @@ static void free_capabilities(struct acpi_power_meter_resource *resource)
int i;
str = &resource->model_number;
for (i = 0; i < 3; i++, str++)
for (i = 0; i < 3; i++, str++) {
kfree(*str);
*str = NULL;
}
}
static int read_capabilities(struct acpi_power_meter_resource *resource)
@ -801,9 +803,7 @@ static int read_capabilities(struct acpi_power_meter_resource *resource)
dev_info(&resource->acpi_dev->dev, "Found ACPI power meter.\n");
goto end;
error:
str = &resource->model_number;
for (i = 0; i < 3; i++, str++)
kfree(*str);
free_capabilities(resource);
end:
kfree(buffer.pointer);
return res;
@ -874,7 +874,6 @@ static int acpi_power_meter_add(struct acpi_device *device)
strcpy(acpi_device_class(device), ACPI_POWER_METER_CLASS);
device->driver_data = resource;
free_capabilities(resource);
res = read_capabilities(resource);
if (res)
goto exit_free;