1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (c) 2023 SUSE LLC
4 * Author: Vlastimil Babka <vbabka@suse.cz>
5 * https://bugzilla.suse.com/attachment.cgi?id=867254
6 * LTP port: Petr Vorel <pvorel@suse.cz>
7 */
8
9 /*\
10 * [Description]
11 *
12 * Bug reproducer for 7e7757876f25 ("mm/mremap: fix vm_pgoff in vma_merge() case 3")
13 */
14
15 #define _GNU_SOURCE
16 #include <unistd.h>
17 #include <stdlib.h>
18 #include <stdio.h>
19 #include <fcntl.h>
20 #include <sys/mman.h>
21
22 #include "tst_test.h"
23 #include "tst_safe_macros.h"
24
25 #define NUM_PAGES 3
26
27 static int fd;
28 static char *buf, *buf2;
29 static int page_size, mmap_size, mremap_size;
30
31 static struct tcase {
32 size_t incompatible;
33 const char *desc;
34 } tcases[] = {
35 {
36 .desc = "all pages with compatible mapping",
37 },
38 {
39 .incompatible = 3,
40 .desc = "third page's mapping incompatible",
41 },
42 {
43 .incompatible = 1,
44 .desc = "first page's mapping incompatible",
45 },
46 };
47
check_pages(void)48 static int check_pages(void)
49 {
50 int fail = 0, i;
51 char val;
52
53 for (i = 0; i < (int)ARRAY_SIZE(tcases); i++) {
54 val = buf[i * page_size];
55 if (val != 0x30 + i) {
56 tst_res(TFAIL, "page %d wrong value %d (0x%x)", i, val - 0x30, val);
57 fail = 1;
58 }
59 }
60
61 return fail;
62 }
63
do_test(unsigned int n)64 static void do_test(unsigned int n)
65 {
66 struct tcase *tc = &tcases[n];
67 int ret;
68
69 tst_res(TINFO, "%s", tc->desc);
70
71 buf = SAFE_MMAP(0, mmap_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
72
73 buf2 = mremap(buf + page_size, page_size, page_size,
74 MREMAP_MAYMOVE|MREMAP_FIXED, buf + mremap_size);
75 if (buf2 == MAP_FAILED)
76 tst_brk(TBROK, "mremap() failed");
77
78 if (tc->incompatible) {
79 ret = mprotect(buf + (tc->incompatible-1)*page_size, page_size, PROT_READ);
80 if (ret == -1)
81 tst_brk(TBROK, "mprotect() failed");
82 }
83
84 buf2 = mremap(buf + mremap_size, page_size, page_size,
85 MREMAP_MAYMOVE|MREMAP_FIXED, buf + page_size);
86 if (buf2 == MAP_FAILED)
87 tst_brk(TBROK, "mremap() failed");
88
89 if (!check_pages())
90 tst_res(TPASS, "mmap/mremap work properly");
91
92 SAFE_MUNMAP(buf, mremap_size);
93 }
94
setup(void)95 static void setup(void)
96 {
97 int ret, i;
98
99 page_size = getpagesize();
100 mmap_size = (NUM_PAGES+1) * page_size;
101 mremap_size = NUM_PAGES * page_size;
102
103 fd = SAFE_OPEN("testfile", O_CREAT | O_RDWR | O_TRUNC, 0600);
104
105 ret = fallocate(fd, 0, 0, mmap_size);
106 if (ret == -1)
107 tst_brk(TBROK, "fallocate() failed");
108
109 buf = SAFE_MMAP(0, mmap_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
110
111 for (i = 0; i < (int)ARRAY_SIZE(tcases)+1; i++)
112 buf[i*page_size] = 0x30 + i;
113
114 /* clear the page tables */
115 SAFE_MUNMAP(buf, mmap_size);
116 }
117
cleanup(void)118 static void cleanup(void)
119 {
120 if (fd > 0)
121 SAFE_CLOSE(fd);
122 }
123
124 static struct tst_test test = {
125 .setup = setup,
126 .cleanup = cleanup,
127 .test = do_test,
128 .needs_tmpdir = 1,
129 .tcnt = ARRAY_SIZE(tcases),
130 .tags = (struct tst_tag[]) {
131 {"linux-git", "7e7757876f25"},
132 {}
133 },
134 };
135