1 /*
2 * Copyright (C) 2015 Yi Zhang <wetpzy@gmail.com>
3 * Li Wang <liwang@redhat.com>
4 *
5 * Licensed under the GNU GPLv2 or later.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
14 * the GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20 /* DESCRIPTION:
21 *
22 * It is a regression test for commit:
23 * http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/
24 * commit/?id=13d60f4
25 *
26 * The implementation of futex doesn't produce unique keys for futexes
27 * in shared huge pages, so threads waiting on different futexes may
28 * end up on the same wait list. This results in incorrect threads being
29 * woken by FUTEX_WAKE.
30 *
31 * Needs to be run as root unless there are already enough huge pages available.
32 * In the fail case, which happens in the CentOS-6.6 kernel (2.6.32-504.8.1),
33 * the tests hangs until it times out after a 30-second wait.
34 *
35 */
36
37 #include <stdio.h>
38 #include <sys/mman.h>
39 #include <fcntl.h>
40 #include <pthread.h>
41 #include <errno.h>
42 #include <sys/time.h>
43 #include <string.h>
44
45 #include "test.h"
46 #include "safe_macros.h"
47 #include "futextest.h"
48 #include "futex_utils.h"
49 #include "lapi/mmap.h"
50
51 #define PATH_MEMINFO "/proc/meminfo"
52 #define PATH_NR_HUGEPAGES "/proc/sys/vm/nr_hugepages"
53 #define PATH_HUGEPAGES "/sys/kernel/mm/hugepages/"
54
55 const char *TCID = "futex_wake04";
56 const int TST_TOTAL = 1;
57
58 static futex_t *futex1, *futex2;
59
60 static struct timespec to = {.tv_sec = 30, .tv_nsec = 0};
61
62 static long orig_hugepages;
63
setup(void)64 static void setup(void)
65 {
66 tst_require_root();
67
68 if ((tst_kvercmp(2, 6, 32)) < 0) {
69 tst_brkm(TCONF, NULL, "This test can only run on kernels "
70 "that are 2.6.32 or higher");
71 }
72
73 if (access(PATH_HUGEPAGES, F_OK))
74 tst_brkm(TCONF, NULL, "Huge page is not supported.");
75
76 tst_tmpdir();
77
78 SAFE_FILE_SCANF(NULL, PATH_NR_HUGEPAGES, "%ld", &orig_hugepages);
79
80 if (orig_hugepages <= 0)
81 SAFE_FILE_PRINTF(NULL, PATH_NR_HUGEPAGES, "%d", 1);
82
83 TEST_PAUSE;
84 }
85
cleanup(void)86 static void cleanup(void)
87 {
88 if (orig_hugepages <= 0)
89 SAFE_FILE_PRINTF(NULL, PATH_NR_HUGEPAGES, "%ld", orig_hugepages);
90
91 tst_rmdir();
92 }
93
read_hugepagesize(void)94 static int read_hugepagesize(void)
95 {
96 FILE *fp;
97 char line[BUFSIZ], buf[BUFSIZ];
98 int val;
99
100 fp = SAFE_FOPEN(cleanup, PATH_MEMINFO, "r");
101 while (fgets(line, BUFSIZ, fp) != NULL) {
102 if (sscanf(line, "%64s %d", buf, &val) == 2)
103 if (strcmp(buf, "Hugepagesize:") == 0) {
104 SAFE_FCLOSE(cleanup, fp);
105 return 1024 * val;
106 }
107 }
108
109 SAFE_FCLOSE(cleanup, fp);
110 tst_brkm(TBROK, NULL, "can't find \"%s\" in %s",
111 "Hugepagesize:", PATH_MEMINFO);
112 }
113
wait_thread1(void * arg LTP_ATTRIBUTE_UNUSED)114 static void *wait_thread1(void *arg LTP_ATTRIBUTE_UNUSED)
115 {
116 futex_wait(futex1, *futex1, &to, 0);
117
118 return NULL;
119 }
120
wait_thread2(void * arg LTP_ATTRIBUTE_UNUSED)121 static void *wait_thread2(void *arg LTP_ATTRIBUTE_UNUSED)
122 {
123 int res;
124
125 res = futex_wait(futex2, *futex2, &to, 0);
126 if (!res)
127 tst_resm(TPASS, "Hi hydra, thread2 awake!");
128 else
129 tst_resm(TFAIL, "Bug: wait_thread2 did not wake after 30 secs.");
130
131 return NULL;
132 }
133
wakeup_thread2(void)134 static void wakeup_thread2(void)
135 {
136 void *addr;
137 int hpsz, pgsz, res;
138 pthread_t th1, th2;
139
140 hpsz = read_hugepagesize();
141 tst_resm(TINFO, "Hugepagesize %i", hpsz);
142
143 /*allocate some shared memory*/
144 addr = mmap(NULL, hpsz, PROT_WRITE | PROT_READ,
145 MAP_SHARED | MAP_ANONYMOUS | MAP_HUGETLB, -1, 0);
146
147 if (addr == MAP_FAILED) {
148 if (errno == ENOMEM) {
149 tst_brkm(TCONF, NULL,
150 "Cannot allocate hugepage, memory too fragmented?");
151 }
152
153 tst_brkm(TBROK | TERRNO, NULL, "Cannot allocate hugepage");
154 }
155
156 pgsz = getpagesize();
157
158 /*apply the first subpage to futex1*/
159 futex1 = addr;
160 *futex1 = 0;
161 /*apply the second subpage to futex2*/
162 futex2 = (futex_t *)((char *)addr + pgsz);
163 *futex2 = 0;
164
165 /*thread1 block on futex1 first,then thread2 block on futex2*/
166 res = pthread_create(&th1, NULL, wait_thread1, NULL);
167 if (res) {
168 tst_brkm(TBROK, NULL, "pthread_create(): %s",
169 tst_strerrno(res));
170 }
171
172 res = pthread_create(&th2, NULL, wait_thread2, NULL);
173 if (res) {
174 tst_brkm(TBROK, NULL, "pthread_create(): %s",
175 tst_strerrno(res));
176 }
177
178 while (wait_for_threads(2))
179 usleep(1000);
180
181 futex_wake(futex2, 1, 0);
182
183 res = pthread_join(th2, NULL);
184 if (res)
185 tst_brkm(TBROK, NULL, "pthread_join(): %s", tst_strerrno(res));
186
187 futex_wake(futex1, 1, 0);
188
189 res = pthread_join(th1, NULL);
190 if (res)
191 tst_brkm(TBROK, NULL, "pthread_join(): %s", tst_strerrno(res));
192
193 SAFE_MUNMAP(NULL, addr, hpsz);
194 }
195
main(int argc,char * argv[])196 int main(int argc, char *argv[])
197 {
198 int lc;
199
200 tst_parse_opts(argc, argv, NULL, NULL);
201
202 setup();
203
204 for (lc = 0; TEST_LOOPING(lc); lc++)
205 wakeup_thread2();
206
207 cleanup();
208 tst_exit();
209 }
210