diff --git a/programs/test/selftest.c b/programs/test/selftest.c
index 61dde5e..e132e4c 100644
--- a/programs/test/selftest.c
+++ b/programs/test/selftest.c
@@ -79,6 +79,7 @@
         if (verbose) {
             mbedtls_printf("  CALLOC(0,1): passed (same non-null)\n");
         }
+        empty2 = NULL;
     } else {
         if (verbose) {
             mbedtls_printf("  CALLOC(0,1): passed (distinct non-null)\n");
@@ -103,6 +104,7 @@
         if (verbose) {
             mbedtls_printf("  CALLOC(1,0): passed (same non-null)\n");
         }
+        empty2 = NULL;
     } else {
         if (verbose) {
             mbedtls_printf("  CALLOC(1,0): passed (distinct non-null)\n");
@@ -119,6 +121,7 @@
             mbedtls_printf("  CALLOC(1): failed (same buffer twice)\n");
         }
         ++failures;
+        buffer2 = NULL;
     } else {
         if (verbose) {
             mbedtls_printf("  CALLOC(1): passed\n");