[PATCH v1 02/17] ACPI: amba: 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/acpi/arm64/amba.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/arm64/amba.c b/drivers/acpi/arm64/amba.c
index 1350083bce5f..7ee431d9464a 100644
--- a/drivers/acpi/arm64/amba.c
+++ b/drivers/acpi/arm64/amba.c
@@ -87,11 +87,12 @@ static int amba_handler_attach(struct acpi_device *adev,
 	 * the amba device we are about to create.
 	 */
 	if (parent)
-		dev->dev.parent = acpi_get_first_physical_node(parent);
+		dev->dev.parent = acpi_bus_get_primary_device(parent);
 
 	device_set_node(&dev->dev, acpi_fwnode_handle(adev));
 
 	ret = amba_device_add(dev, &iomem_resource);
+	put_device(dev->dev.parent);
 	if (ret) {
 		dev_err(&adev->dev, "%s(): amba_device_add() failed (%d)\n",
 		       __func__, ret);
-- 
2.51.0