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/"
28static long hpage_size;
29static int  fd = -1;
30
31static 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
60static void setup(void)
61{
62	hpage_size = SAFE_READ_MEMINFO(MEMINFO_HPAGE_SIZE)*1024;
63}
64
65static void cleanup(void)
66{
67	if (fd > 0)
68		SAFE_CLOSE(fd);
69}
70
71static 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