Explicitly initialize the group tg_exitsem with sem_init(). The existing logic worked because the correct initialization value is all zero, but it is better to initialize the semaphore explicitly. Noted by Jouko Holopainen.

sched/group/group_create.c

@@ -241,12 +241,18 @@ int group_allocate(FAR struct task_tcb_s *tcb, uint8_t ttype)
       return ret;
     }
 
+#ifndef CONFIG_DISABLE_PTHREAD
   /* Initialize the pthread join semaphore */
 
-#ifndef CONFIG_DISABLE_PTHREAD
   (void)sem_init(&group->tg_joinsem, 0, 1);
 #endif
 
+#if defined(CONFIG_SCHED_WAITPID) && !defined(CONFIG_SCHED_HAVE_PARENT)
+  /* Initialize the exit/wait semaphores */
+
+  (void)sem_init(&group->tg_exitsem, 0, 0);
+#endif
+
   return OK;
 }
 

sched/signal/sig_nanosleep.c

@@ -167,6 +167,11 @@ int nanosleep(FAR const struct timespec *rqtp, FAR struct timespec *rmtp)
       systime_t remaining;
       int ticks;
 
+      /* REVISIT: The conversion from time to ticks and back could
+       * be avoided.  clock_timespec_subtract() would be used instead
+       * to get the time difference.
+       */
+
       /* First get the number of clock ticks that we were requested to
        * wait.
        */