diff --git a/Include/internal/pycore_pymem.h b/Include/internal/pycore_pymem.h
index d61ff6ee4b77d6..535f99e8cc52ef 100644
--- a/Include/internal/pycore_pymem.h
+++ b/Include/internal/pycore_pymem.h
@@ -162,7 +162,7 @@ PyAPI_FUNC(int) _PyMem_SetDefaultAllocator(
    - PYMEM_DEADBYTE dead (newly freed) memory
    - PYMEM_FORBIDDENBYTE: untouchable bytes at each end of a block
 
-   Byte patterns 0xCB, 0xBB and 0xFB have been replaced with 0xCD, 0xDD and
+   Byte patterns 0xCB, 0xDB and 0xFB have been replaced with 0xCD, 0xDD and
    0xFD to use the same values than Windows CRT debug malloc() and free().
    If modified, _PyMem_IsPtrFreed() should be updated as well. */
 #define PYMEM_CLEANBYTE      0xCD
diff --git a/Modules/gcmodule.c b/Modules/gcmodule.c
index 766f8e0c67fa8e..b1e802e33e4985 100644
--- a/Modules/gcmodule.c
+++ b/Modules/gcmodule.c
@@ -1921,6 +1921,8 @@ _PyGC_Dump(PyGC_Head *g)
     _PyObject_Dump(FROM_GC(g));
 }
 
+
+#ifdef Py_DEBUG
 static int
 visit_validate(PyObject *op, void *parent_raw)
 {
@@ -1931,6 +1933,7 @@ visit_validate(PyObject *op, void *parent_raw)
     }
     return 0;
 }
+#endif
 
 
 /* extension modules might be compiled with GC support so these