diff --git a/xen/common/sched/null.c b/xen/common/sched/null.c
index 7e31440e5b..c8e327e3cd 100644
--- a/xen/common/sched/null.c
+++ b/xen/common/sched/null.c
@@ -557,7 +557,7 @@ static void cf_check null_unit_remove(
 
     cpu = sched_unit_master(unit);
     npc = get_sched_res(cpu)->sched_priv;
-    if ( npc->unit )
+    if ( npc->unit == unit )
         unit_deassign(prv, unit);
 
  out: