ACPI / bind: Use (put|get)_device() on ACPI device objects too (a104b4d4) · Commits · 戴 / test

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>

drivers/acpi/glue.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -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;
		}

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