奇怪的问题，在CHECKED OS下有问题

我的驱动在RELEASE的WIN2K下没有问题，但是在CHECKED BUILD的WINXP下却会出现问题，并提示
Assertion Failed :busInfo != NULL
source file xxx..\pnpirp.c LINE 2210
全我看了下WIN2K的代码，位于IopQueryLegacyBusInformation的函数中
NTSTATUS
IopQueryLegacyBusInformation (
    IN PDEVICE_OBJECT DeviceObject,
    OUT LPGUID InterfaceGuid,          OPTIONAL
    OUT INTERFACE_TYPE *InterfaceType, OPTIONAL
    OUT ULONG *BusNumber               OPTIONAL
    )

/*++

Routine Description:

    This routine queries the specified DeviceObject for its legacy bus
    information.

Parameters:

    DeviceObject - The device object to be queried.

    InterfaceGuid = Supplies a pointer to receive the device's interface type
        GUID.

    Interface = Supplies a pointer to receive the device's interface type.

    BusNumber = Supplies a pointer to receive the device's bus number.

Return Value:

    Returns NTSTATUS.

--*/
{
    IO_STACK_LOCATION irpSp;
    NTSTATUS status;
    PLEGACY_BUS_INFORMATION busInfo;

    PAGED_CODE();

    //
    // Initialize the stack location to pass to IopSynchronousCall()
    //

    RtlZeroMemory(&irpSp, sizeof(IO_STACK_LOCATION));

    //
    // Set the function codes.
    //

    irpSp.MajorFunction = IRP_MJ_PNP;
    irpSp.MinorFunction = IRP_MN_QUERY_LEGACY_BUS_INFORMATION;

    //
    // Make the call and return.
    //

    status = IopSynchronousCall(DeviceObject, &irpSp, &busInfo);
    if (NT_SUCCESS(status)) {

        if (busInfo == NULL) {

            //
            // The device driver LIED to us.  Bad, bad, bad device driver.
            //

            PDEVICE_NODE deviceNode;

            deviceNode = DeviceObject->DeviceObjectExtension->DeviceNode;

            if (deviceNode && deviceNode->ServiceName.Buffer) {

                DbgPrint("*** IopQueryLegacyBusInformation - Driver %wZ returned STATUS_SUCCESS\n", &deviceNode->ServiceName);
                DbgPrint("    for IRP_MN_QUERY_LEGACY_BUS_INFORMATION, and a NULL POINTER.\n");
            }

            ASSERT(busInfo != NULL);

        } else {
            if (ARGUMENT_PRESENT(InterfaceGuid)) {
                *InterfaceGuid = busInfo->BusTypeGuid;
            }
            if (ARGUMENT_PRESENT(InterfaceType)) {
                *InterfaceType = busInfo->LegacyBusType;
            }
            if (ARGUMENT_PRESENT(BusNumber)) {
                *BusNumber = busInfo->BusNumber;
            }
            ExFreePool(busInfo);
        }
    }
    return status;
}
也就是说在调用IopSynchronousCall(DeviceObject, &irpSp, &busInfo);
后busInfo==NULL，想知道有哪些原因导致这个问题呢？？