1 files changed, 9 insertions, 0 deletions
diff --git a/sem_post.c b/sem_post.c
index 91f9755..c7a7a3c 100644
--- a/sem_post.c
+++ b/sem_post.c
@@ -82,6 +82,15 @@ sem_post (sem_t * sem)
     }
   else if ((result = pthread_mutex_lock (&s->lock)) == 0)
     {
+      /* See sem_destroy.c
+       */
+      if (*sem == NULL)
+        {
+          (void) pthread_mutex_unlock (&s->lock);
+          result = EINVAL;
+          return -1;
+        }
+
       if (s->value < SEM_VALUE_MAX)
 	{
 #ifdef NEED_SEM