diff --git a/WHATS_NEW_DM b/WHATS_NEW_DM
index 13cc57916..e7c01246c 100644
--- a/WHATS_NEW_DM
+++ b/WHATS_NEW_DM
@@ -1,5 +1,6 @@
 Version 1.02.68 -
 ==================================
+  Fix valgrind error reports in free of pool chunks with DEBUG_MEM.
   Aling size of structure chunk for fast pool allocator to 8 bytes.
   Simplify some pointer operations in dm_free_aux() debug code.
   Remove unused dbg_malloc.h file from source tree.
diff --git a/libdm/mm/pool-fast.c b/libdm/mm/pool-fast.c
index 386776196..e14d073ca 100644
--- a/libdm/mm/pool-fast.c
+++ b/libdm/mm/pool-fast.c
@@ -300,6 +300,12 @@ static struct chunk *_new_chunk(struct dm_pool *p, size_t s)
 
 static void _free_chunk(struct chunk *c)
 {
+#ifdef VALGRIND_POOL
+#  ifdef DEBUG_MEM
+	if (c)
+		VALGRIND_MAKE_MEM_UNDEFINED(c + 1, c->end - (char *) (c + 1));
+#  endif
+#endif
 	dm_free(c);
 }