--- a/io/tst-closefrom.c
+++ b/io/tst-closefrom.c
@@ -39,7 +39,7 @@
 
   const int maximum_fd = lowfd + NFDS - 1;
   const int half_fd = lowfd + NFDS / 2;
-  const int gap = maximum_fd / 4;
+  const int gap = lowfd + NFDS / 4;
 
   /* Close half of the descriptors and check result.  */
   closefrom (half_fd);
@@ -49,7 +49,7 @@
       TEST_COMPARE (fcntl (i, F_GETFL), -1);
       TEST_COMPARE (errno, EBADF);
     }
-  for (int i = 0; i < half_fd; i++)
+  for (int i = lowfd; i < half_fd; i++)
     TEST_VERIFY (fcntl (i, F_GETFL) > -1);
 
   /* Create some gaps, close up to a threshold, and check result.  */
@@ -65,7 +65,7 @@
       TEST_COMPARE (fcntl (i, F_GETFL), -1);
       TEST_COMPARE (errno, EBADF);
     }
-  for (int i = 0; i < gap; i++)
+  for (int i = lowfd; i < gap; i++)
     TEST_VERIFY (fcntl (i, F_GETFL) > -1);
 
   /* Close the remmaining but the last one.  */
--- a/sysdeps/unix/sysv/linux/tst-close_range.c
+++ b/sysdeps/unix/sysv/linux/tst-close_range.c
@@ -189,7 +189,7 @@
 
   support_stack_free (&stack);
 
-  for (int i = 0; i < NFDS; i++)
+  for (int i = lowfd; i < lowfd + NFDS; i++)
     TEST_VERIFY (fcntl (i, F_GETFL) > -1);
 
   support_descriptors_check (descrs2);
@@ -240,13 +240,13 @@
   /* Create some gaps, close up to a threshold, and check result.  */
   static int gap_close[] = { 57, 78, 81, 82, 84, 90 };
   for (int i = 0; i < array_length (gap_close); i++)
-    xclose (gap_close[i]);
+    xclose (lowfd + gap_close[i]);
 
   TEST_COMPARE (close_range (half_fd + 1, gap_1, CLOSE_RANGE_CLOEXEC), 0);
   for (int i = half_fd + 1; i < gap_1; i++)
     {
       int flags = fcntl (i, F_GETFD);
-      if (is_in_array (gap_close, array_length (gap_close), i))
+      if (is_in_array (gap_close, array_length (gap_close), i - lowfd))
         TEST_COMPARE (flags, -1);
       else
         {