should not stop inside critical sections delimited by memory
 locking/unlocking instructions.

    Facility: DEBUG, VMS Debugger

    Explanation: The debugger has limited support for debugging of
    critical sections delimited by memory locking/unlocking (e.g.
    LDx_L/STx_C (load-locked/store-conditional) instructions. The
    exception mechanisms used by the debugger causes the lock-flag
    set by the locking instruction to be cleared. This action affects
    the behavior of subsequent instructions that rely on memory being
    locked.

    User Action: Cancel or deactivate all eventpoints (watchpoints,
    breakpoints, etc.) that might trigger while the application being
    debugged is executing the critical section; a STEP issued from
    the load_lock instruction should now step over the critical
    section. Eventpoints then may be safely reset.