1/*
2 * Copyright (c) 2015-2017 Red Hat, Inc.
3 *
4 * This program is free software;  you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY;  without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
12 * the GNU General Public License for more details.
13 */
14
15/*
16 * DESCRIPTION
17 *	shmget()/shmat() fails to allocate huge pages shared memory segment
18 *	with EINVAL if its size is not in the range [ N*HUGE_PAGE_SIZE - 4095,
19 *	N*HUGE_PAGE_SIZE ]. This is a problem in the memory segment size round
20 *	up algorithm. The requested size is rounded up to PAGE_SIZE (4096), but
21 *	if this roundup does not match HUGE_PAGE_SIZE (2Mb) boundary - the
22 *	allocation fails.
23 *
24 *	This bug is present in all RHEL6 versions, but not in RHEL7. It looks
25 *	like this was fixed in mainline kernel > v3.3 by the following patches:
26 *
27 *	091d0d5 (shm: fix null pointer deref when userspace specifies
28 *		 invalid hugepage size)
29 *	af73e4d (hugetlbfs: fix mmap failure in unaligned size request)
30 *	42d7395 (mm: support more pagesizes for MAP_HUGETLB/SHM_HUGETLB)
31 *	40716e2 (hugetlbfs: fix alignment of huge page requests)
32 *
33 * AUTHORS
34 *	Vladislav Dronov <vdronov@redhat.com>
35 *	Li Wang <liwang@redhat.com>
36 *
37 */
38
39#include "hugetlb.h"
40
41static long page_size;
42static long hpage_size;
43static long hugepages;
44
45#define N 4
46
47void setup(void)
48{
49	save_nr_hugepages();
50	page_size = getpagesize();
51	hpage_size = SAFE_READ_MEMINFO("Hugepagesize:") * 1024;
52
53	hugepages = N + 1;
54	set_sys_tune("nr_hugepages", hugepages, 1);
55}
56
57void cleanup(void)
58{
59	restore_nr_hugepages();
60}
61
62void shm_test(int size)
63{
64	int shmid;
65	char *shmaddr;
66
67	shmid = shmget(IPC_PRIVATE, size, 0600 | IPC_CREAT | SHM_HUGETLB);
68	if (shmid < 0)
69		tst_brk(TBROK | TERRNO, "shmget failed");
70
71	shmaddr = shmat(shmid, 0, 0);
72	if (shmaddr == (char *)-1) {
73		shmctl(shmid, IPC_RMID, NULL);
74		tst_brk(TFAIL | TERRNO,
75			 "Bug: shared memory attach failure.");
76	}
77
78	shmaddr[0] = 1;
79	tst_res(TINFO, "allocated %d huge bytes", size);
80
81	if (shmdt((const void *)shmaddr) != 0) {
82		shmctl(shmid, IPC_RMID, NULL);
83		tst_brk(TFAIL | TERRNO, "Detach failure.");
84	}
85
86	shmctl(shmid, IPC_RMID, NULL);
87}
88
89static void test_hugeshmat(void)
90{
91	unsigned int i;
92
93	const int tst_sizes[] = {
94		N * hpage_size - page_size,
95		N * hpage_size - page_size - 1,
96		hpage_size,
97		hpage_size + 1
98	};
99
100	for (i = 0; i < ARRAY_SIZE(tst_sizes); ++i)
101		shm_test(tst_sizes[i]);
102
103	tst_res(TPASS, "No regression found.");
104}
105
106static struct tst_test test = {
107	.needs_root = 1,
108	.needs_tmpdir = 1,
109	.test_all = test_hugeshmat,
110	.setup = setup,
111	.cleanup = cleanup,
112};
113