refclock_wwv.c fix from Dave Mills

bk: 45385446EkqQLObLeQO9XH38ArhI4g

diff --git a/ntpd/refclock_wwv.c b/ntpd/refclock_wwv.c
index 9a13079841f3cb7f5c4a127bd311e12b7676bb77..b7e0d9a6b1df9e955516614e95bf7640b32a023e 100644 (file)
--- a/ntpd/refclock_wwv.c
+++ b/ntpd/refclock_wwv.c
@@ -764,6 +764,9 @@ wwv_shutdown(
 
        pp = peer->procptr;
        up = (struct wwvunit *)pp->unitptr;
+       if (up == NULL)
+               return;
+
        io_closeclock(&pp->io);
 #ifdef ICOM
        if (up->fd_icom > 0)