If you enable driver verifier on usbstor.sys, hibernate the system and then resume from hibernation, you may experience a system crash with bug code DRIVER_VERIFIER_IOMANAGER_VIOLATION (c9) and the first argument equal to 228. The memory dump will point to usbstor.sys as the faulting module, specifically in the USBSTOR_FdoSetPowerD0Completion routine.
Code 228 indicates that a driver's completion routine has not marked the IRP pending if the PendingReturned field was set in the IRP passed to it. This may cause the operating system to hang, especially if an error is returned by the stack.
This issue in usbstor.sys will be fixed in the next version of Windows