1 /*
2 * vma01 - test not merging a VMA which cloned from parent process
3 *
4 * This program is used for testing the following upstream commit:
5 * 965f55dea0e331152fa53941a51e4e16f9f06fae
6 *
7 * The cloned VMA shares the anon_vma lock with the parent process's
8 * VMA. If we do the merge, more vmas (even the new range is only
9 * for current process) use the perent process's anon_vma lock. This
10 * introduces scalability issues. find_mergeable_anon_vma() already
11 * considers this case.
12 *
13 * This test program clones VMA and checks /proc/self/maps file, on
14 * an unpatched kernel, there is a single 6*ps VMA for the child
15 * like this:
16 *
17 * 7fee32989000-7fee3298f000 -w-p 00000000 00:00 0
18 *
19 * On a patched kernel, there are two 3*ps VMAs like this:
20 *
21 * 7f55bbd47000-7f55bbd4a000 -w-p 00000000 00:00 0
22 * 7f55bbd4a000-7f55bbd4d000 -w-p 00000000 00:00 0
23 *
24 * Copyright (C) 2011 Red Hat, Inc.
25 * This program is free software; you can redistribute it and/or
26 * modify it under the terms of version 2 of the GNU General Public
27 * License as published by the Free Software Foundation.
28 *
29 * This program is distributed in the hope that it would be useful,
30 * but WITHOUT ANY WARRANTY; without even the implied warranty of
31 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
32 *
33 * Further, this software is distributed without any warranty that it
34 * is free of the rightful claim of any third person regarding
35 * infringement or the like. Any license provided herein, whether
36 * implied or otherwise, applies only to this software file. Patent
37 * licenses, if any, provided herein do not apply to combinations of
38 * this program with other software, or any other product whatsoever.
39 *
40 * You should have received a copy of the GNU General Public License
41 * along with this program; if not, write the Free Software
42 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
43 * 02110-1301, USA.
44 */
45 #include <sys/types.h>
46 #include <sys/mman.h>
47 #include <sys/wait.h>
48 #include <unistd.h>
49 #include <stdio.h>
50 #include <stdlib.h>
51 #include <string.h>
52
53 #include "test.h"
54
55 #define MAPS_FILE "/proc/self/maps"
56
57 char *TCID = "vma01";
58 int TST_TOTAL = 1;
59
60 static void check_vma(void);
61 static void create_bighole(void);
62 static void *get_end_addr(void *addr_s);
63 static void check_status(int status);
64 static void setup(void);
65 static void cleanup(void);
66
67 static unsigned long ps;
68 static void *p;
69
main(int argc,char ** argv)70 int main(int argc, char **argv)
71 {
72 int lc;
73
74 tst_parse_opts(argc, argv, NULL, NULL);
75
76 ps = sysconf(_SC_PAGE_SIZE);
77 setup();
78
79 for (lc = 0; TEST_LOOPING(lc); lc++) {
80 tst_count = 0;
81
82 check_vma();
83 }
84 cleanup();
85 tst_exit();
86 }
87
check_vma(void)88 static void check_vma(void)
89 {
90 int status;
91 int topdown;
92 void *t, *u, *x;
93
94 create_bighole();
95 t = mmap(p, 3 * ps, PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
96 if (t == MAP_FAILED)
97 tst_brkm(TBROK | TERRNO, cleanup, "mmap");
98 memset(t, 1, ps);
99
100 switch (fork()) {
101 case -1:
102 tst_brkm(TBROK | TERRNO, cleanup, "fork");
103 case 0:
104 memset(t, 2, ps);
105 u = mmap(t + 3 * ps, 3 * ps, PROT_WRITE,
106 MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
107 if (u == MAP_FAILED) {
108 perror("mmap");
109 exit(255);
110 }
111 topdown = (u > t) ? 0 : 1;
112 printf("parent: t = %p\n", t);
113 printf("child : u = %p\n", u);
114 memset(u, 2, ps);
115
116 if (topdown) {
117 x = get_end_addr(u);
118 printf("child : x = %p\n", x);
119 if (x == t + 3 * ps)
120 exit(1);
121 else if (x == t && get_end_addr(x) == t + 3 * ps)
122 exit(0);
123 } else {
124 x = get_end_addr(t);
125 printf("child : x = %p\n", x);
126 if (x == t + 6 * ps)
127 exit(1);
128 else if (x == u && get_end_addr(x) == t + 6 * ps)
129 exit(0);
130 }
131 exit(255);
132 default:
133 if (waitpid(-1, &status, 0) == -1)
134 tst_brkm(TBROK | TERRNO, cleanup, "waitpid");
135 if (!WIFEXITED(status))
136 tst_brkm(TBROK, cleanup, "child exited abnormally.");
137 check_status(WEXITSTATUS(status));
138 break;
139 }
140 }
141
create_bighole(void)142 static void create_bighole(void)
143 {
144 void *t;
145
146 /*
147 * |-3*ps-|
148 * |------|------|------| hole
149 * t p
150 * |======|------| top-down alloc
151 * |------|======| bottom-up alloc
152 */
153 t = mmap(NULL, 9 * ps, PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
154 if (t == MAP_FAILED)
155 tst_brkm(TBROK | TERRNO, cleanup, "mmap");
156 memset(t, 'a', ps);
157 p = t + 3 * ps;
158 if (munmap(t, 9 * ps) == -1)
159 tst_brkm(TBROK | TERRNO, cleanup, "munmap");
160 }
161
get_end_addr(void * addr_s)162 static void *get_end_addr(void *addr_s)
163 {
164 FILE *fp;
165 void *s, *t;
166 char buf[BUFSIZ];
167
168 fp = fopen(MAPS_FILE, "r");
169 if (fp == NULL)
170 tst_brkm(TBROK | TERRNO, cleanup, "fopen");
171 while (fgets(buf, BUFSIZ, fp) != NULL) {
172 if (sscanf(buf, "%p-%p ", &s, &t) != 2)
173 continue;
174 if (addr_s == s) {
175 tst_resm(TINFO, "s = %p, t = %p", s, t);
176 fclose(fp);
177 return t;
178 }
179 }
180 fclose(fp);
181 tst_brkm(TBROK, cleanup, "no matched s = %p found.", addr_s);
182 }
183
check_status(int status)184 static void check_status(int status)
185 {
186 switch (status) {
187 case 0:
188 tst_resm(TPASS, "two 3*ps VMAs found.");
189 break;
190 case 1:
191 if (tst_kvercmp(3, 0, 0) < 0) {
192 tst_resm(TCONF, "A single 6*ps VMA found. You may need"
193 " to back port kernel commit 965f55d "
194 "to fix this scalability issue.");
195 } else {
196 tst_resm(TFAIL, "A single 6*ps VMA found.");
197 }
198 break;
199 default:
200 tst_brkm(TBROK, cleanup, "unexpected VMA found.");
201 }
202 }
203
setup(void)204 static void setup(void)
205 {
206 tst_sig(FORK, DEF_HANDLER, cleanup);
207
208 TEST_PAUSE;
209 }
210
cleanup(void)211 static void cleanup(void)
212 {
213 }
214