diff --git a/src/mesa/program/prog_parameter.c b/src/mesa/program/prog_parameter.c
index f1b7b71834e..a8940f88733 100644
--- a/src/mesa/program/prog_parameter.c
+++ b/src/mesa/program/prog_parameter.c
@@ -223,7 +223,7 @@ _mesa_reserve_parameter_storage(struct gl_program_parameter_list *paramList,
 
       paramList->ParameterValues = (gl_constant_value *)
          align_realloc(paramList->ParameterValues,         /* old buf */
-                       oldNum * 4 * sizeof(gl_constant_value),/* old sz */
+                       oldValNum * 4 * sizeof(gl_constant_value),/* old sz */
                        /* Overallocate the size by 12 because matrix rows can
                         * be allocated partially but fetch_state always writes
                         * 4 components (16 bytes).