From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
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@xxxxxxxxx>
---
drivers/acpi/glue.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
Index: linux-pm/drivers/acpi/glue.c
===================================================================
--- linux-pm.orig/drivers/acpi/glue.c
+++ linux-pm/drivers/acpi/glue.c
@@ -217,6 +217,7 @@ int acpi_bind_one(struct device *dev, ac
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, ac
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, ac
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;
}
--
To unsubscribe from this list: send the line "unsubscribe linux-acpi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
