[PATCH v2] platform/x86: asus-wireless: Fail probe when there is no ACPI match

[Linmao Li]

Every platform driver can be forced to match a device that doesn't match
its list of device IDs because of device_match_driver_override(), so
platform drivers that rely on the existence of a device's ACPI companion
object need to verify its presence.

asus_wireless_probe() returns success when acpi_match_acpi_device()
finds no match, leaving behind an input device that never reports
anything because the notify handler is not installed.  Worse, when the
driver is force-bound to a device without an ACPI companion, probe
still succeeds and stores a NULL companion pointer, which
asus_wireless_remove() later passes to acpi_dev_remove_notify_handler(),
leading to a NULL pointer dereference on unbind.

Return -ENODEV when the device does not match the ID table.  This also
covers the missing-companion case, because acpi_match_acpi_device()
rejects a NULL device.

Fixes: f7e648027d7e ("platform/x86: asus-wireless: Convert ACPI driver to a platform one")
Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Linmao Li <lilinmao@xxxxxxxxxx>
---
v2: Fail probe when the ACPI ID match fails instead of adding a
    separate ACPI companion check at the top of probe (Rafael).

 drivers/platform/x86/asus-wireless.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/platform/x86/asus-wireless.c b/drivers/platform/x86/asus-wireless.c
index 2b494bf3cba8..d33853a1baf3 100644
--- a/drivers/platform/x86/asus-wireless.c
+++ b/drivers/platform/x86/asus-wireless.c
@@ -155,7 +155,7 @@ static int asus_wireless_probe(struct platform_device *pdev)
 
 	id = acpi_match_acpi_device(device_ids, adev);
 	if (!id)
-		return 0;
+		return -ENODEV;
 
 	data->hswc_params = (const struct hswc_params *)id->driver_data;
 
-- 
2.25.1