diff --git a/xen/common/sched/credit.c b/xen/common/sched/credit.c
index 6dcf6b2c8b..485e52bd7c 100644
--- a/xen/common/sched/credit.c
+++ b/xen/common/sched/credit.c
@@ -1589,6 +1589,10 @@ static void cf_check csched_tick(void *_cpu)
     struct csched_pcpu *spc = CSCHED_PCPU(cpu);
     struct csched_private *prv = CSCHED_PRIV(sr->scheduler);
 
+    /* Handle race of timer disabling vs. firing when switching scheduler. */
+    if ( !spc )
+        return;
+
     spc->tick++;
 
     /*