1 // SPDX-License-Identifier: LGPL-2.1-or-later
2 /*
3 * Copyright (C) 2005-2006 IBM Corporation.
4 * Author: Mel Gorman
5 */
6
7 /*\
8 * [Description]
9 *
10 * fadvise() on some kernels can cause the reservation counter to get
11 * corrupted. The problem is that the patches are allocated for the
12 * reservation but not faulted in at the time of allocation. The counters
13 * do not get updated and effectively "leak". This test identifies whether
14 * the kernel is vulnerable to the problem or not. It's fixed in kernel
15 * by commit f2deae9d4e70793568ef9e85d227abb7bef5b622.
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 long hpage_size;
29 static int fd = -1;
30
run_test(void)31 static void run_test(void)
32 {
33 void *p;
34 unsigned long initial_rsvd, map_rsvd, fadvise_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 SAFE_POSIX_FADVISE(fd, 0, hpage_size, POSIX_FADV_WILLNEED);
47 fadvise_rsvd = SAFE_READ_MEMINFO(MEMINFO_HPAGE_RSVD);
48 tst_res(TINFO, "Reserve count after fadvise: %lu", fadvise_rsvd);
49
50 memset(p, 1, hpage_size);
51
52 SAFE_MUNMAP(p, hpage_size);
53 SAFE_CLOSE(fd);
54 end_rsvd = SAFE_READ_MEMINFO(MEMINFO_HPAGE_RSVD);
55 tst_res(TINFO, "Reserve count after close: %lu", end_rsvd);
56
57 TST_EXP_EQ_LU(end_rsvd, initial_rsvd);
58 }
59
setup(void)60 static void setup(void)
61 {
62 hpage_size = SAFE_READ_MEMINFO(MEMINFO_HPAGE_SIZE)*1024;
63 }
64
cleanup(void)65 static void cleanup(void)
66 {
67 if (fd > 0)
68 SAFE_CLOSE(fd);
69 }
70
71 static struct tst_test test = {
72 .tags = (struct tst_tag[]) {
73 {"linux-git", "f2deae9d4e70"},
74 {}
75 },
76 .needs_root = 1,
77 .mntpoint = MNTPOINT,
78 .needs_hugetlbfs = 1,
79 .setup = setup,
80 .cleanup = cleanup,
81 .test_all = run_test,
82 .hugepages = {1, TST_NEEDS},
83 };
84