Fix math.factorial KeyboardInterrupt segfault. Thanks Amaury for report and diagnosis.

Misc/NEWS

@@ -132,6 +132,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #16305: Fix a segmentation fault occurring when interrupting
+  math.factorial.
+
 - Issue #14398: Fix size truncation and overflow bugs in the bz2 module.
 
 - Issue #16220: wsgiref now always calls close() on an iterable response.

Modules/mathmodule.c

@@ -1330,14 +1330,13 @@ factorial_odd_part(unsigned long n)
         Py_DECREF(outer);
         outer = tmp;
     }
-
-    goto done;
+    Py_DECREF(inner);
+    return outer;
 
   error:
     Py_DECREF(outer);
-  done:
     Py_DECREF(inner);
-    return outer;
+    return NULL;
 }
 
 /* Lookup table for small factorial values */