diff -r 4b0907c6a08c xen/common/schedule.c
--- a/xen/common/schedule.c	Tue Oct 11 12:02:58 2011 +0100
+++ b/xen/common/schedule.c	Fri Oct 14 11:55:00 2011 +0200
@@ -763,7 +763,7 @@ static long domain_watchdog(struct domai
     if ( !test_bit(id, &d->watchdog_inuse_map) )
     {
         spin_unlock(&d->watchdog_lock);
-        return -EEXIST;
+        return -EINVAL;
     }
 
     if ( timeout == 0 )