diff --git a/testcases/kernel/syscalls/mlock/mlock03.c b/testcases/kernel/syscalls/mlock/mlock03.c
index 8bc65701c..0fc3fa8ed 100644
--- a/testcases/kernel/syscalls/mlock/mlock03.c
+++ b/testcases/kernel/syscalls/mlock/mlock03.c
@@ -1,119 +1,68 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
- * Stack size mapping is decreased through mlock/munlock call.
- *
- * This is to test kernel if it has a problem with shortening [stack]
- * mapping through several loops of mlock/munlock of /proc/self/maps.
- *
- * From:
- * munlock     76KiB bfef2000-bff05000 rw-p 00000000 00:00 0          [stack]
- *
- * To:
- * munlock     44KiB bfefa000-bff05000 rw-p 00000000 00:00 0          [stack]
- *
- * with more iterations - could drop to 0KiB.
- *
  * Copyright (C) 2010  Red Hat, Inc.
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of version 2 of the GNU General Public
- * License as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it would be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
- *
- * Further, this software is distributed without any warranty that it
- * is free of the rightful claim of any third person regarding
- * infringement or the like.  Any license provided herein, whether
- * implied or otherwise, applies only to this software file.  Patent
- * licenses, if any, provided herein do not apply to combinations of
- * this program with other software, or any other product whatsoever.
+ */
+
+/*\
+ * [Description]
  *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
- * 02110-1301, USA.
+ * This case is designed to test kernel whether met a problem with shortening
+ * [stack] mapping through several loops of mlock/munlock of /proc/self/maps.
  */
+
 #include <sys/mman.h>
 #include <stdio.h>
 #include <string.h>
-#include "test.h"
+#include <pwd.h>
+#include "tst_test.h"
+#include "tst_safe_stdio.h"
 
 #define KB 1024
 
-char *TCID = "mlock03";
-int TST_TOTAL = 1;
-
-static void setup(void);
-static void cleanup(void);
-
-int main(int argc, char *argv[])
+static void verify_mlock(void)
 {
-	int lc;
 	long from, to;
 	long first = -1, last = -1;
 	char b[KB];
 	FILE *fp;
 
-	tst_parse_opts(argc, argv, NULL, NULL);
-
-	setup();
+	fp = SAFE_FOPEN("/proc/self/maps", "r");
+	while (!feof(fp)) {
+		if (!fgets(b, KB - 1, fp))
+			break;
+		b[strlen(b) - 1] = '\0';
+		if (sscanf(b, "%lx-%lx", &from, &to) != 2) {
+			tst_res(TFAIL, "parse %s start and end address failed",
+					b);
+			continue;
+		}
 
-	for (lc = 0; TEST_LOOPING(lc); lc++) {
-		fp = fopen("/proc/self/maps", "r");
-		if (fp == NULL)
-			tst_brkm(TBROK | TERRNO, cleanup, "fopen");
-		while (!feof(fp)) {
-			if (!fgets(b, KB - 1, fp))
-				break;
-			b[strlen(b) - 1] = '\0';
-			sscanf(b, "%lx-%lx", &from, &to);
+		/* Record the initial stack size. */
+		if (strstr(b, "[stack]") != NULL)
+			first = (to - from) / KB;
 
-			/* Record the initial stack size. */
-			if (lc == 0 && strstr(b, "[stack]") != NULL)
-				first = (to - from) / KB;
+		tst_res(TINFO, "mlock[%lx,%lx]", from, to);
+		if (mlock((const void *)from, to - from) == -1)
+			tst_res(TINFO | TERRNO, "mlock failed");
 
-			switch (lc & 1) {
-			case 0:
-				if (mlock((const void *)from, to - from) == -1)
-					tst_resm(TINFO | TERRNO,
-						 "mlock failed");
-				break;
-			case 1:
-				if (munlock((void *)from, to - from) == -1)
-					tst_resm(TINFO | TERRNO,
-						 "munlock failed");
-				break;
-			default:
-				break;
-			}
-			tst_resm(TINFO, "%s from %lx to %0lx",
-				 (lc & 1) ? "munlock" : "mlock", from, to);
+		tst_res(TINFO, "munlock [%lx,%lx]", from, to);
+		if (munlock((void *)from, to - from) == -1)
+			tst_res(TINFO | TERRNO, "munlock failed");
 
-			/* Record the final stack size. */
-			if (strstr(b, "[stack]") != NULL)
-				last = (to - from) / KB;
-		}
-		fclose(fp);
+		/* Record the final stack size. */
+		if (strstr(b, "[stack]") != NULL)
+			last = (to - from) / KB;
 	}
-	tst_resm(TINFO, "starting stack size is %ld", first);
-	tst_resm(TINFO, "final stack size is %ld", last);
+	SAFE_FCLOSE(fp);
+
+	tst_res(TINFO, "starting stack size is %ld", first);
+	tst_res(TINFO, "final stack size is %ld", last);
 	if (last < first)
-		tst_resm(TFAIL, "stack size is decreased.");
+		tst_res(TFAIL, "stack size is decreased.");
 	else
-		tst_resm(TPASS, "stack size is not decreased.");
-
-	cleanup();
-	tst_exit();
+		tst_res(TPASS, "stack size is not decreased.");
 }
 
-void setup(void)
-{
-	tst_require_root();
-
-	tst_sig(FORK, DEF_HANDLER, cleanup);
-	TEST_PAUSE;
-}
-
-void cleanup(void)
-{
-}
+static struct tst_test test = {
+	.test_all = verify_mlock,
+};
