1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2010 Red Hat, Inc.
4 */
5
6 /*\
7 * [Description]
8 *
9 * This case is a regression test on old RHEL5.
10 *
11 * Stack size mapping is decreased through mlock/munlock call.
12 * See the following url:
13 * https://bugzilla.redhat.com/show_bug.cgi?id=643426
14 *
15 * This is to test kernel if it has a problem with shortening [stack]
16 * mapping through several loops of mlock/munlock of /proc/self/maps.
17 *
18 * From:
19 * munlock 76KiB bfef2000-bff05000 rw-p 00000000 00:00 0 [stack]
20 *
21 * To:
22 * munlock 44KiB bfefa000-bff05000 rw-p 00000000 00:00 0 [stack]
23 *
24 * with more iterations - could drop to 0KiB.
25 */
26
27 #include <sys/mman.h>
28 #include <stdio.h>
29 #include <string.h>
30 #include <pwd.h>
31 #include "tst_test.h"
32 #include "tst_safe_stdio.h"
33
verify_mlock(void)34 static void verify_mlock(void)
35 {
36 long from, to;
37 long first = -1, last = -1;
38 char b[TST_KB];
39 FILE *fp;
40
41 fp = SAFE_FOPEN("/proc/self/maps", "r");
42 while (!feof(fp)) {
43 if (!fgets(b, TST_KB - 1, fp))
44 break;
45 b[strlen(b) - 1] = '\0';
46 if (sscanf(b, "%lx-%lx", &from, &to) != 2) {
47 tst_brk(TBROK, "parse %s start and end address failed",
48 b);
49 continue;
50 }
51
52 /* Record the initial stack size. */
53 if (strstr(b, "[stack]") != NULL)
54 first = (to - from) / TST_KB;
55
56 tst_res(TINFO, "mlock [%lx,%lx]", from, to);
57 if (mlock((const void *)from, to - from) == -1)
58 tst_res(TINFO | TERRNO, "mlock failed");
59
60 tst_res(TINFO, "munlock [%lx,%lx]", from, to);
61 if (munlock((void *)from, to - from) == -1)
62 tst_res(TINFO | TERRNO, "munlock failed");
63
64 /* Record the final stack size. */
65 if (strstr(b, "[stack]") != NULL)
66 last = (to - from) / TST_KB;
67 }
68 SAFE_FCLOSE(fp);
69
70 tst_res(TINFO, "starting stack size is %ld", first);
71 tst_res(TINFO, "final stack size is %ld", last);
72 if (last < first)
73 tst_res(TFAIL, "stack size is decreased.");
74 else
75 tst_res(TPASS, "stack size is not decreased.");
76 }
77
78 static struct tst_test test = {
79 .test_all = verify_mlock,
80 };
81