diff --git a/mm/mm_heap/mm_initialize.c b/mm/mm_heap/mm_initialize.c
index fa41069b2fc..e49e249ffad 100644
--- a/mm/mm_heap/mm_initialize.c
+++ b/mm/mm_heap/mm_initialize.c
@@ -82,6 +82,8 @@ void mm_addregion(FAR struct mm_heap_s *heap, FAR void *heapstart,
   DEBUGASSERT(heapsize <= MMSIZE_MAX + 1);
 #endif
 
+  mm_takesemaphore(heap);
+
   /* Adjust the provide heap start and size so that they are both aligned
    * with the MM_MIN_CHUNK size.
    */
@@ -127,6 +129,8 @@ void mm_addregion(FAR struct mm_heap_s *heap, FAR void *heapstart,
   /* Add the single, large free node to the nodelist */
 
   mm_addfreechunk(heap, node);
+
+  mm_givesemaphore(heap);
 }
 
 /****************************************************************************