From 5ea77118aaae09c29cea6e7fd543bf409d317fbc Mon Sep 17 00:00:00 2001
From: Gregory Nutt <gnutt@nuttx.org>
Date: Wed, 10 Aug 2016 07:37:25 -0600
Subject: [PATCH] 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   | 8 +++++++-
 sched/signal/sig_nanosleep.c | 5 +++++
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/sched/group/group_create.c b/sched/group/group_create.c
index 3b3cb6be08..2aecb9c12b 100644
--- a/sched/group/group_create.c
+++ b/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;
 }
 
diff --git a/sched/signal/sig_nanosleep.c b/sched/signal/sig_nanosleep.c
index 0ac8e7fadb..4a492f0c85 100644
--- a/sched/signal/sig_nanosleep.c
+++ b/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.
        */