--- /dev/null
+/* Test qsort with invalid comparison functions.
+ Copyright (C) 2023 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <array_length.h>
+#include <stdlib.h>
+#include <support/check.h>
+
+/* Invalid comparison function that always returns -1. */
+static int
+invalid_compare_1 (const void *a1, const void *b1)
+{
+ const int *a = a1;
+ const int *b = b1;
+ /* Check that the marker value matches, which means that we are
+ likely within the array. */
+ TEST_COMPARE (*a, 842523635);
+ TEST_COMPARE (*b, 842523635);
+ TEST_VERIFY_EXIT (*a == 842523635);
+ TEST_VERIFY_EXIT (*b == 842523635);
+ return -1;
+}
+
+/* Invalid comparison function that always returns 1. */
+static int
+invalid_compare_2 (const void *a1, const void *b1)
+{
+ const int *a = a1;
+ const int *b = b1;
+ TEST_COMPARE (*a, 842523635);
+ TEST_COMPARE (*b, 842523635);
+ TEST_VERIFY_EXIT (*a == 842523635);
+ TEST_VERIFY_EXIT (*b == 842523635);
+ return 1;
+}
+
+static int
+do_test (void)
+{
+ int array[] = {842523635, 842523635, 842523635, 842523635, 842523635};
+ qsort (array, array_length (array), sizeof (array[0]), invalid_compare_1);
+ qsort (array, array_length (array), sizeof (array[0]), invalid_compare_2);
+ return 0;
+}
+
+#include <support/test-driver.c>