From 2b3a5dabe89e330413af403246b648c1890f368f Mon Sep 17 00:00:00 2001 From: Linmao Li Date: Mon, 6 Jul 2026 09:25:11 +0800 Subject: [PATCH] platform/surface: acpi-notify: Check ACPI companion before use MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Since 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(), platform drivers that rely on the existence of a device's ACPI companion object should verify its presence. san_probe() dereferences the result of ACPI_COMPANION() when installing the GSBUS address space handler, so force-binding the driver to a device without an ACPI companion leads to a NULL pointer dereference. The dereference was introduced when the probe function was switched from ACPI_HANDLE() to ACPI_COMPANION(). Check the ACPI companion against NULL and return -ENODEV when it is missing, like commit e4865a56d013 ("ACPI: driver: Check ACPI_COMPANION() against NULL during probe") does for the core ACPI platform drivers. Fixes: a9e10e587304 ("ACPI: scan: Extend acpi_walk_dep_device_list()") Signed-off-by: Linmao Li Link: https://patch.msgid.link/20260706012512.524359-2-lilinmao@kylinos.cn Reviewed-by: Ilpo Järvinen Signed-off-by: Ilpo Järvinen --- drivers/platform/surface/surface_acpi_notify.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/platform/surface/surface_acpi_notify.c b/drivers/platform/surface/surface_acpi_notify.c index a9dcb0bbe90e..593a7aba6243 100644 --- a/drivers/platform/surface/surface_acpi_notify.c +++ b/drivers/platform/surface/surface_acpi_notify.c @@ -777,12 +777,16 @@ static int san_consumer_links_setup(struct platform_device *pdev) static int san_probe(struct platform_device *pdev) { - struct acpi_device *san = ACPI_COMPANION(&pdev->dev); struct ssam_controller *ctrl; + struct acpi_device *san; struct san_data *data; acpi_status astatus; int status; + san = ACPI_COMPANION(&pdev->dev); + if (!san) + return -ENODEV; + ctrl = ssam_client_bind(&pdev->dev); if (IS_ERR(ctrl)) return PTR_ERR(ctrl) == -ENODEV ? -EPROBE_DEFER : PTR_ERR(ctrl);