From: Rafael J. Wysocki <rafael@xxxxxxxxxx>
In read_domain_devices(), acpi_bus_get_device() is called to obtain
the ACPI device object attached to the given ACPI handle and
subsequently that object is passed to get_device() for reference
counting, but there is a window between the acpi_bus_get_device()
and get_device() calls in which the ACPI device object in question
may go away.
To address this issue, make read_domain_devices() use
acpi_bus_get_acpi_device() to reference count and return the given
ACPI device object in one go and export that function to modules.
While at it, also make read_domain_devices() and
remove_domain_devices() use acpi_dev_put() instead of calling
put_device() directly on the ACPI device objects returned by
acpi_bus_get_acpi_device().
Signed-off-by: Rafael J. Wysocki <rafael@xxxxxxxxxx>
---
drivers/acpi/scan.c | 1 +
drivers/hwmon/acpi_power_meter.c | 13 +++++--------
2 files changed, 6 insertions(+), 8 deletions(-)
Index: linux-pm/drivers/hwmon/acpi_power_meter.c
===================================================================
--- linux-pm.orig/drivers/hwmon/acpi_power_meter.c
+++ linux-pm/drivers/hwmon/acpi_power_meter.c
@@ -535,7 +535,7 @@ static void remove_domain_devices(struct
sysfs_remove_link(resource->holders_dir,
kobject_name(&obj->dev.kobj));
- put_device(&obj->dev);
+ acpi_dev_put(obj);
}
kfree(resource->domain_devices);
@@ -597,18 +597,15 @@ static int read_domain_devices(struct ac
continue;
/* Create a symlink to domain objects */
- resource->domain_devices[i] = NULL;
- if (acpi_bus_get_device(element->reference.handle,
- &resource->domain_devices[i]))
+ obj = acpi_bus_get_acpi_device(element->reference.handle);
+ resource->domain_devices[i] = obj;
+ if (!obj)
continue;
- obj = resource->domain_devices[i];
- get_device(&obj->dev);
-
res = sysfs_create_link(resource->holders_dir, &obj->dev.kobj,
kobject_name(&obj->dev.kobj));
if (res) {
- put_device(&obj->dev);
+ acpi_dev_put(obj);
resource->domain_devices[i] = NULL;
}
}
Index: linux-pm/drivers/acpi/scan.c
===================================================================
--- linux-pm.orig/drivers/acpi/scan.c
+++ linux-pm/drivers/acpi/scan.c
@@ -608,6 +608,7 @@ struct acpi_device *acpi_bus_get_acpi_de
{
return handle_to_device(handle, get_acpi_device);
}
+EXPORT_SYMBOL_GPL(acpi_bus_get_acpi_device);
static struct acpi_device_bus_id *acpi_device_bus_id_match(const char *dev_id)
{
