diff --git a/sched/sched/sched_waitid.c b/sched/sched/sched_waitid.c
index 3b119d3143b..0c8c895b14e 100644
--- a/sched/sched/sched_waitid.c
+++ b/sched/sched/sched_waitid.c
@@ -152,11 +152,11 @@ int nx_waitid(int idtype, id_t id, FAR siginfo_t *info, int options)
 
 #ifdef CONFIG_SMP
   irqstate_t flags = enter_critical_section();
-#endif
-
+#else
   /* Disable pre-emption so that nothing changes while the loop executes */
 
   sched_lock();
+#endif
 
   /* Verify that this task actually has children and that the requested
    * TCB is actually a child of this task.
@@ -417,10 +417,11 @@ int nx_waitid(int idtype, id_t id, FAR siginfo_t *info, int options)
     }
 
 errout:
-  sched_unlock();
 
 #ifdef CONFIG_SMP
   leave_critical_section(flags);
+#else
+  sched_unlock();
 #endif
 
   return ret;
diff --git a/sched/sched/sched_waitpid.c b/sched/sched/sched_waitpid.c
index 40534b6c819..d787ca01f95 100644
--- a/sched/sched/sched_waitpid.c
+++ b/sched/sched/sched_waitpid.c
@@ -78,11 +78,11 @@ pid_t nx_waitpid(pid_t pid, int *stat_loc, int options)
 
 #ifdef CONFIG_SMP
   irqstate_t flags = enter_critical_section();
-#endif
-
+#else
   /* Disable pre-emption so that nothing changes in the following tests */
 
   sched_lock();
+#endif
 
   /* Get the TCB corresponding to this PID */
 
@@ -169,10 +169,11 @@ pid_t nx_waitpid(pid_t pid, int *stat_loc, int options)
   ret = pid;
 
 errout:
-  sched_unlock();
 
 #ifdef CONFIG_SMP
   leave_critical_section(flags);
+#else
+  sched_unlock();
 #endif
 
   return ret;
@@ -217,11 +218,11 @@ pid_t nx_waitpid(pid_t pid, int *stat_loc, int options)
 
 #ifdef CONFIG_SMP
   irqstate_t flags = enter_critical_section();
-#endif
-
+#else
   /* Disable pre-emption so that nothing changes while the loop executes */
 
   sched_lock();
+#endif
 
   /* Verify that this task actually has children and that the requested PID
    * is actually a child of this task.
@@ -464,10 +465,11 @@ pid_t nx_waitpid(pid_t pid, int *stat_loc, int options)
   ret = pid;
 
 errout:
-  sched_unlock();
 
 #ifdef CONFIG_SMP
   leave_critical_section(flags);
+#else
+  sched_unlock();
 #endif
 
   return ret;