[PATCH v1 06/17] platform/x86: serdev_helpers: Switch to use acpi_bus_get_primary_device()

[Rafael J. Wysocki]

From: "Rafael J. Wysocki" <rafael.j.wysocki at intel.com>

Replace acpi_get_first_physical_node() that is slated for removal
with acpi_bus_get_primary_device() that takes a reference to the
device it is about to return.

This addresses a potential use-after-free that may occur if the
device returned by acpi_get_first_physical_node() is removed right
after dropping its ACPI companion's physical_node_lock in that
function.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki at intel.com>
---
 drivers/platform/x86/serdev_helpers.h | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/platform/x86/serdev_helpers.h b/drivers/platform/x86/serdev_helpers.h
index 57eac75805e2..20267e1941f1 100644
--- a/drivers/platform/x86/serdev_helpers.h
+++ b/drivers/platform/x86/serdev_helpers.h
@@ -74,8 +74,7 @@ get_serdev_controller(const char *serial_ctrl_hid,
 		return ERR_PTR(-ENODEV);
 	}
 
-	/* get_first_physical_node() returns a weak ref */
-	parent = get_device(acpi_get_first_physical_node(adev));
+	parent = acpi_bus_get_primary_device(adev);
 	acpi_dev_put(adev);
 	if (!parent) {
 		pr_err("error could not get %s/%s serial-ctrl physical node\n",
-- 
2.51.0