[PATCH v1 08/17] platform/x86: x86-android-tablets: Use acpi_bus_get_primary_device()

[Rafael J. Wysocki]

From: "Rafael J. Wysocki" <rafael.j.wysocki@xxxxxxxxx>

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@xxxxxxxxx>
---
 drivers/platform/x86/x86-android-tablets/core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/platform/x86/x86-android-tablets/core.c b/drivers/platform/x86/x86-android-tablets/core.c
index cfff7f5eac5d..2c262f117235 100644
--- a/drivers/platform/x86/x86-android-tablets/core.c
+++ b/drivers/platform/x86/x86-android-tablets/core.c
@@ -390,7 +390,6 @@ static int gpio_secondary_fwnode_init(struct device *parent,
 {
 	const struct software_node *const *swnode;
 	struct fwnode_handle *fwnode;
-	struct device *phys_dev;
 	int ret;
 
 	if (!node_group)
@@ -418,7 +417,8 @@ static int gpio_secondary_fwnode_init(struct device *parent,
 		if (WARN_ON(!fwnode))
 			return -ENOENT;
 
-		phys_dev = acpi_get_first_physical_node(to_acpi_device(dev));
+		struct device *phys_dev __free(put_device) =
+				acpi_bus_get_primary_device(to_acpi_device(dev));
 		if (!phys_dev)
 			return dev_err_probe(parent, -ENODEV,
 					     "No physical device for ACPI GPIO dev: %pfwP\n",
-- 
2.51.0