1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (c) 2015-2017 Red Hat, Inc.
4 *
5 *
6 * DESCRIPTION
7 * shmget()/shmat() fails to allocate huge pages shared memory segment
8 * with EINVAL if its size is not in the range [ N*HUGE_PAGE_SIZE - 4095,
9 * N*HUGE_PAGE_SIZE ]. This is a problem in the memory segment size round
10 * up algorithm. The requested size is rounded up to PAGE_SIZE (4096), but
11 * if this roundup does not match HUGE_PAGE_SIZE (2Mb) boundary - the
12 * allocation fails.
13 *
14 * This bug is present in all RHEL6 versions, but not in RHEL7. It looks
15 * like this was fixed in mainline kernel > v3.3 by the following patches:
16 *
17 * 091d0d55b286 (shm: fix null pointer deref when userspace specifies
18 * invalid hugepage size)
19 * af73e4d9506d (hugetlbfs: fix mmap failure in unaligned size request)
20 * 42d7395feb56 (mm: support more pagesizes for MAP_HUGETLB/SHM_HUGETLB)
21 * 40716e29243d (hugetlbfs: fix alignment of huge page requests)
22 *
23 * AUTHORS
24 * Vladislav Dronov <vdronov@redhat.com>
25 * Li Wang <liwang@redhat.com>
26 *
27 */
28
29 #include "hugetlb.h"
30
31 static long page_size;
32 static long hpage_size;
33
34 #define N 4
35
setup(void)36 void setup(void)
37 {
38 if (tst_hugepages != test.request_hugepages)
39 tst_brk(TCONF, "Not enough hugepages for testing.");
40
41 page_size = getpagesize();
42 hpage_size = SAFE_READ_MEMINFO("Hugepagesize:") * 1024;
43 }
44
shm_test(int size)45 void shm_test(int size)
46 {
47 int shmid;
48 char *shmaddr;
49
50 shmid = shmget(IPC_PRIVATE, size, 0600 | IPC_CREAT | SHM_HUGETLB);
51 if (shmid < 0)
52 tst_brk(TBROK | TERRNO, "shmget failed");
53
54 shmaddr = shmat(shmid, 0, 0);
55 if (shmaddr == (char *)-1) {
56 shmctl(shmid, IPC_RMID, NULL);
57 tst_brk(TFAIL | TERRNO,
58 "Bug: shared memory attach failure.");
59 }
60
61 shmaddr[0] = 1;
62 tst_res(TINFO, "allocated %d huge bytes", size);
63
64 if (shmdt((const void *)shmaddr) != 0) {
65 shmctl(shmid, IPC_RMID, NULL);
66 tst_brk(TFAIL | TERRNO, "Detach failure.");
67 }
68
69 shmctl(shmid, IPC_RMID, NULL);
70 }
71
test_hugeshmat(void)72 static void test_hugeshmat(void)
73 {
74 unsigned int i;
75
76 const int tst_sizes[] = {
77 N * hpage_size - page_size,
78 N * hpage_size - page_size - 1,
79 hpage_size,
80 hpage_size + 1
81 };
82
83 for (i = 0; i < ARRAY_SIZE(tst_sizes); ++i)
84 shm_test(tst_sizes[i]);
85
86 tst_res(TPASS, "No regression found.");
87 }
88
89 static struct tst_test test = {
90 .needs_root = 1,
91 .needs_tmpdir = 1,
92 .test_all = test_hugeshmat,
93 .setup = setup,
94 .request_hugepages = N + 1,
95 .tags = (const struct tst_tag[]) {
96 {"linux-git", "091d0d55b286"},
97 {"linux-git", "af73e4d9506d"},
98 {"linux-git", "42d7395feb56"},
99 {"linux-git", "40716e29243d"},
100 {}
101 }
102 };
103