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ACPI / bind: Use (put|get)_device() on ACPI device objects too

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When associating a "physical" device with an ACPI device object
acpi_bind_one() only uses get_device() to increment the reference
counter of the former, but there is no reason not to do that with
the latter too.  Among other things, that may help to avoid
use-after-free when an ACPI device object is freed without calling
acpi_unbind_one() for all "physical" devices associated with it
(that only can happen in buggy code, but then it's better if the
kernel doesn't crash as a result of a bug).

For this reason, modify acpi_bind_one() to apply get_device() to
the ACPI device object too and update acpi_unbind_one() to drop
that reference using put_device() as appropriate.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Lan Tianyu <tianyu.lan@intel.com>
This commit is contained in:
Rafael J. Wysocki 2013-11-14 23:18:32 +01:00
parent 3a83f99249
commit a104b4d467
1 changed files with 5 additions and 1 deletions
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6
drivers/acpi/glue.c
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@ -217,6 +217,7 @@ int acpi_bind_one(struct device *dev, acpi_handle handle)
if (!acpi_dev)
return -EINVAL;
get_device(&acpi_dev->dev);
get_device(dev);
physical_node = kzalloc(sizeof(*physical_node), GFP_KERNEL);
if (!physical_node) {
@ -243,6 +244,7 @@ int acpi_bind_one(struct device *dev, acpi_handle handle)
goto err;
put_device(dev);
put_device(&acpi_dev->dev);
return 0;
}
if (pn->node_id == node_id) {
@ -282,6 +284,7 @@ int acpi_bind_one(struct device *dev, acpi_handle handle)
err:
ACPI_COMPANION_SET(dev, NULL);
put_device(dev);
put_device(&acpi_dev->dev);
return retval;
}
EXPORT_SYMBOL_GPL(acpi_bind_one);
@ -307,8 +310,9 @@ int acpi_unbind_one(struct device *dev)
sysfs_remove_link(&acpi_dev->dev.kobj, physnode_name);
sysfs_remove_link(&dev->kobj, "firmware_node");
ACPI_COMPANION_SET(dev, NULL);
/* acpi_bind_one() increase refcnt by one. */
/* Drop references taken by acpi_bind_one(). */
put_device(dev);
put_device(&acpi_dev->dev);
kfree(entry);
break;
}