diff --git a/sched/pthread/pthread_setschedparam.c b/sched/pthread/pthread_setschedparam.c
index 3c04cfb0232..f5ce5c5391d 100644
--- a/sched/pthread/pthread_setschedparam.c
+++ b/sched/pthread/pthread_setschedparam.c
@@ -1,7 +1,8 @@
 /****************************************************************************
  * sched/pthread/pthread_setschedparam.c
  *
- *   Copyright (C) 2007, 2008, 2012, 2015 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007, 2008, 2012, 2015, 2018 Gregory Nutt. All rights
+ *     reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -105,10 +106,6 @@ int pthread_setschedparam(pthread_t thread, int policy,
 
   sinfo("thread ID=%d policy=%d param=0x%p\n", thread, policy, param);
 
-  /* Set the errno to some non-zero value (failsafe) */
-
-  set_errno(EINVAL);
-
   /* Let sched_setscheduler do all of the work */
 
   ret = sched_setscheduler((pid_t)thread, policy, param);
diff --git a/sched/sched/sched.h b/sched/sched/sched.h
index eea2a3b1c2c..d083dc6a59d 100644
--- a/sched/sched/sched.h
+++ b/sched/sched/sched.h
@@ -1,7 +1,7 @@
 /****************************************************************************
  * sched/sched/sched.h
  *
- *   Copyright (C) 2007-2014, 2016 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2014, 2016, 2018 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -63,6 +63,10 @@
  * tasks built into the design).
  */
 
+#if CONFIG_MAX_TASKS & (CONFIG_MAX_TASKS - 1)
+#  error CONFIG_MAX_TASKS must be power of 2
+#endif
+
 #define MAX_TASKS_MASK           (CONFIG_MAX_TASKS-1)
 #define PIDHASH(pid)             ((pid) & MAX_TASKS_MASK)
 
diff --git a/sched/semaphore/sem_recover.c b/sched/semaphore/sem_recover.c
index bccb904e07b..6305f0d35e8 100644
--- a/sched/semaphore/sem_recover.c
+++ b/sched/semaphore/sem_recover.c
@@ -105,7 +105,7 @@ void nxsem_recover(FAR struct tcb_s *tcb)
       nxsem_canceled(tcb, sem);
 
       /* And increment the count on the semaphore.  This releases the count
-       * that was taken by sem_post().  This count decremented the semaphore
+       * that was taken by sem_wait().  This count decremented the semaphore
        * count to negative and caused the thread to be blocked in the first
        * place.
        */
diff --git a/sched/task/task_create.c b/sched/task/task_create.c
index a1d07e1d8ec..2cc8c1a9118 100644
--- a/sched/task/task_create.c
+++ b/sched/task/task_create.c
@@ -103,11 +103,11 @@ static int thread_create(FAR const char *name, uint8_t ttype, int priority,
       goto errout;
     }
 
+#ifdef HAVE_TASK_GROUP
   /* Allocate a new task group with privileges appropriate for the parent
    * thread type.
    */
 
-#ifdef HAVE_TASK_GROUP
   ret = group_allocate(tcb, ttype);
   if (ret < 0)
     {
@@ -157,9 +157,9 @@ static int thread_create(FAR const char *name, uint8_t ttype, int priority,
 
   (void)task_argsetup(tcb, name, argv);
 
+#ifdef HAVE_TASK_GROUP
   /* Now we have enough in place that we can join the group */
 
-#ifdef HAVE_TASK_GROUP
   ret = group_initialize(tcb);
   if (ret < 0)
     {
diff --git a/sched/task/task_setcanceltype.c b/sched/task/task_setcanceltype.c
index b7536f46258..3c08c5d3206 100644
--- a/sched/task/task_setcanceltype.c
+++ b/sched/task/task_setcanceltype.c
@@ -52,7 +52,7 @@
  ****************************************************************************/
 
 /****************************************************************************
- * Name: task_setcancelstate
+ * Name: task_setcanceltype
  *
  * Description:
  *   The task_setcanceltype() function atomically both sets the calling
diff --git a/sched/wdog/wd_delete.c b/sched/wdog/wd_delete.c
index a497c1146e0..7b56bede466 100644
--- a/sched/wdog/wd_delete.c
+++ b/sched/wdog/wd_delete.c
@@ -1,7 +1,8 @@
 /****************************************************************************
  * sched/wdog/wd_delete.c
  *
- *   Copyright (C) 2007-2009, 2014, 2016 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2009, 2014, 2016, 2018 Gregory Nutt. All rights
+ *     reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -113,9 +114,7 @@ int wd_delete(WDOG_ID wdog)
       sched_kfree(wdog);
     }
 
-  /* This was a pre-allocated timer.  This function should not be called for
-   * statically allocated timers.
-   */
+  /* Check if this is pre-allocated timer. */
 
   else if (!WDOG_ISSTATIC(wdog))
     {
@@ -129,6 +128,13 @@ int wd_delete(WDOG_ID wdog)
       leave_critical_section(flags);
     }
 
+  /* This function should not be called for statically allocated timers. */
+
+  else
+    {
+      leave_critical_section(flags);
+    }
+
   /* Return success */
 
   return OK;