diff --git a/fs/mmap/fs_mmap.c b/fs/mmap/fs_mmap.c
index f72633acc90..d4bb97f29d5 100644
--- a/fs/mmap/fs_mmap.c
+++ b/fs/mmap/fs_mmap.c
@@ -74,6 +74,13 @@ static int file_mmap_(FAR struct file *filep, FAR void *start,
    */
 
 #ifdef CONFIG_DEBUG_FEATURES
+  /* A flags with MAP_PRIVATE and MAP_SHARED is invalid. */
+
+  if ((flags & MAP_PRIVATE) && (flags & MAP_SHARED))
+    {
+      return -EINVAL;
+    }
+
   /* Fixed mappings and protections are not currently supported.  These
    * options could be supported in the KERNEL build with an MMU, but that
    * logic is not in place.
diff --git a/fs/mmap/fs_munmap.c b/fs/mmap/fs_munmap.c
index 85449c1ee5f..41f25a43b34 100644
--- a/fs/mmap/fs_munmap.c
+++ b/fs/mmap/fs_munmap.c
@@ -69,6 +69,13 @@ static int file_munmap_(FAR void *start, size_t length, bool kernel)
       mm_map_unlock();
     }
 
+  /* If entry don't find, the start and length is invalid. */
+
+  if (entry == NULL)
+    {
+      return -EINVAL;
+    }
+
   return ret;
 }