diff --git a/sched/sched/sched_timerexpiration.c b/sched/sched/sched_timerexpiration.c
index 82c86450e1f..546fb9f246b 100644
--- a/sched/sched/sched_timerexpiration.c
+++ b/sched/sched/sched_timerexpiration.c
@@ -100,6 +100,10 @@ static clock_t g_timer_tick;
 
 static atomic_t g_timer_interval;
 
+#ifdef CONFIG_SCHED_TICKLESS
+static unsigned int g_timernested;
+#endif
+
 /****************************************************************************
  * Private Functions
  ****************************************************************************/
@@ -470,12 +474,19 @@ clock_t nxsched_timer_update(clock_t ticks, bool noswitches)
 void nxsched_timer_expiration(void)
 {
   clock_t ticks;
+  irqstate_t flags = enter_critical_section();
 
   /* Get the interval associated with last expiration */
 
+  g_timernested++;
+
   up_timer_gettick(&ticks);
 
   nxsched_timer_update(ticks, false);
+
+  g_timernested--;
+
+  leave_critical_section(flags);
 }
 
 /****************************************************************************
@@ -519,17 +530,20 @@ void nxsched_reassess_timer(void)
 {
   clock_t ticks;
 
-  /* Cancel the timer and get the current time */
+  if (!g_timernested)
+    {
+      /* Cancel the timer and get the current time */
 
 #ifdef CONFIG_SCHED_TICKLESS_ALARM
-  up_alarm_tick_cancel(&ticks);
+      up_alarm_tick_cancel(&ticks);
 #else
-  clock_t elapsed;
-  up_timer_gettick(&ticks);
-  up_timer_tick_cancel(&elapsed);
+      clock_t elapsed;
+      up_timer_gettick(&ticks);
+      up_timer_tick_cancel(&elapsed);
 #endif
 
-  nxsched_timer_update(ticks, true);
+      nxsched_timer_update(ticks, true);
+    }
 }
 
 /****************************************************************************
diff --git a/sched/wdog/wd_start.c b/sched/wdog/wd_start.c
index aca3d3f0751..77a50e4f4cf 100644
--- a/sched/wdog/wd_start.c
+++ b/sched/wdog/wd_start.c
@@ -85,14 +85,6 @@
 #define wdparm_to_ptr(type, arg) ((type)(uintptr_t)arg)
 #define ptr_to_wdparm(ptr)       wdparm_to_ptr(wdparm_t, ptr)
 
-/****************************************************************************
- * Private Data
- ****************************************************************************/
-
-#ifdef CONFIG_SCHED_TICKLESS
-static unsigned int g_wdtimernested;
-#endif
-
 /****************************************************************************
  * Private Functions
  ****************************************************************************/
@@ -121,14 +113,6 @@ static inline_function void wd_expiration(clock_t ticks)
 
   flags = spin_lock_irqsave(&g_wdspinlock);
 
-#ifdef CONFIG_SCHED_TICKLESS
-  /* Increment the nested watchdog timer count to handle cases where wd_start
-   * is called in the watchdog callback functions.
-   */
-
-  g_wdtimernested++;
-#endif
-
   /* Process the watchdog at the head of the list as well as any
    * other watchdogs that became ready to run at this time
    */
@@ -173,12 +157,6 @@ static inline_function void wd_expiration(clock_t ticks)
       flags = spin_lock_irqsave(&g_wdspinlock);
     }
 
-#ifdef CONFIG_SCHED_TICKLESS
-  /* Decrement the nested watchdog timer count */
-
-  g_wdtimernested--;
-#endif
-
   spin_unlock_irqrestore(&g_wdspinlock, flags);
 }
 
@@ -313,7 +291,7 @@ int wd_start_abstick(FAR struct wdog_s *wdog, clock_t ticks,
 
   reassess |= wd_insert(wdog, ticks, wdentry, arg);
 
-  if (!g_wdtimernested && reassess)
+  if (reassess)
     {
       /* Resume the interval timer that will generate the next
        * interval event. If the timer at the head of the list changed,