Index: drivers/usb/usbhub/fdo.c
===================================================================
--- drivers/usb/usbhub/fdo.c	(revision 71259)
+++ drivers/usb/usbhub/fdo.c	(working copy)
@@ -1035,6 +1035,9 @@
         {
             // construct instance id buffer
             Index = swprintf(Buffer, L"%04d&%s", HubDeviceExtension->InstanceCount, SerialBuffer) + 1;
+            
+            ExFreePool(SerialBuffer);
+            
             UsbChildExtension->usInstanceId.Buffer = (LPWSTR)ExAllocatePool(NonPagedPool, Index * sizeof(WCHAR));
             if (UsbChildExtension->usInstanceId.Buffer == NULL)
             {
@@ -1047,7 +1050,6 @@
             //
             RtlCopyMemory(UsbChildExtension->usInstanceId.Buffer, Buffer, Index * sizeof(WCHAR));
             UsbChildExtension->usInstanceId.Length = UsbChildExtension->usInstanceId.MaximumLength = Index * sizeof(WCHAR);
-            ExFreePool(SerialBuffer);
 
             DPRINT("Usb InstanceId %wZ InstanceCount %x\n", &UsbChildExtension->usInstanceId, HubDeviceExtension->InstanceCount);
             return Status;