1 // SPDX-License-Identifier: LGPL-2.1-or-later
2 /*
3 * Copyright (C) 2005-2006 IBM Corporation.
4 * Author: Eric B Munson and Mel Gorman
5 */
6
7 /*\
8 * [Description]
9 *
10 * madvise() on some kernels can cause the reservation counter to get
11 * corrupted. The problem is that the patches are allocated
12 * for the reservation but not faulted in at the time of allocation. The
13 * counters do not get updated and effectively "leak". This test
14 * identifies whether the kernel is vulnerable to the problem or not.
15 * It is fixed in kernel by commit f2deae9d4e70
16 */
17
18 #define _GNU_SOURCE
19 #include <stdio.h>
20 #include <sys/mount.h>
21 #include <limits.h>
22 #include <sys/param.h>
23 #include <sys/types.h>
24
25 #include "hugetlb.h"
26
27 #define MNTPOINT "hugetlbfs/"
28 static int fd = -1;
29 static long hpage_size;
30
run_test(void)31 static void run_test(void)
32 {
33 void *p;
34 unsigned long initial_rsvd, map_rsvd, madvise_rsvd, end_rsvd;
35
36 fd = tst_creat_unlinked(MNTPOINT, 0);
37
38 initial_rsvd = SAFE_READ_MEMINFO(MEMINFO_HPAGE_RSVD);
39 tst_res(TINFO, "Reserve count before map: %lu", initial_rsvd);
40
41 p = SAFE_MMAP(NULL, hpage_size, PROT_READ|PROT_WRITE, MAP_SHARED,
42 fd, 0);
43 map_rsvd = SAFE_READ_MEMINFO(MEMINFO_HPAGE_RSVD);
44 tst_res(TINFO, "Reserve count after map: %lu", map_rsvd);
45
46 if (madvise(p, hpage_size, MADV_WILLNEED) == -1)
47 tst_brk(TBROK|TERRNO, "madvise()");
48 madvise_rsvd = SAFE_READ_MEMINFO(MEMINFO_HPAGE_RSVD);
49 tst_res(TINFO, "Reserve count after madvise: %lu", madvise_rsvd);
50
51 SAFE_MUNMAP(p, hpage_size);
52 SAFE_CLOSE(fd);
53 end_rsvd = SAFE_READ_MEMINFO(MEMINFO_HPAGE_RSVD);
54 tst_res(TINFO, "Reserve count after close(): %lu", end_rsvd);
55
56 TST_EXP_EQ_LU(end_rsvd, initial_rsvd);
57 }
58
setup(void)59 static void setup(void)
60 {
61 hpage_size = SAFE_READ_MEMINFO("Hugepagesize:")*1024;
62 }
63
cleanup(void)64 static void cleanup(void)
65 {
66 if (fd >= 0)
67 SAFE_CLOSE(fd);
68 }
69
70 static struct tst_test test = {
71 .tags = (struct tst_tag[]) {
72 {"linux-git", "f2deae9d4e70"},
73 {}
74 },
75 .needs_root = 1,
76 .mntpoint = MNTPOINT,
77 .needs_hugetlbfs = 1,
78 .needs_tmpdir = 1,
79 .setup = setup,
80 .cleanup = cleanup,
81 .test_all = run_test,
82 .hugepages = {1, TST_NEEDS},
83 };
84