Re:[PATCH] Drivers: hv: vmbus: Check ACPI companion before use

["jiale yao" <19888972804@163.com>]

At 2026-10-17 14:43:13, "Jiale Yao" <yaojiale02@163.com> wrote:
>Platform drivers can be forced to bind to devices outside their match
>tables through driver_override. vmbus_acpi_add() assumes that every bound
>device has an ACPI companion and dereferences it without checking.
>
>Return -ENODEV when the companion is absent to avoid a NULL pointer
>dereference.
>

Fixes: 9c8434238041 ("Drivers: hv: vmbus: Convert acpi_device to more generic platform_device")

>Signed-off-by: Jiale Yao <yaojiale02@163.com>
>---
> drivers/hv/vmbus_drv.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
>diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
>index 4692687cdbf3..28f459679406 100644
>--- a/drivers/hv/vmbus_drv.c
>+++ b/drivers/hv/vmbus_drv.c
>@@ -2571,10 +2571,14 @@ EXPORT_SYMBOL_GPL(vmbus_free_mmio);
> #ifdef CONFIG_ACPI
> static int vmbus_acpi_add(struct platform_device *pdev)
> {
>+	struct acpi_device *ancestor;
>+	struct acpi_device *device;
> 	acpi_status result;
> 	int ret_val = -ENODEV;
>-	struct acpi_device *ancestor;
>-	struct acpi_device *device = ACPI_COMPANION(&pdev->dev);
>+
>+	device = ACPI_COMPANION(&pdev->dev);
>+	if (!device)
>+		return -ENODEV;
> 
> 	vmbus_root_device = &device->dev;
> 
>-- 
>2.34.1