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 SAFE_FILE_PRINTF(NULL, PATH_NR_HUGEPAGES, "%d", 1);
80
81 TEST_PAUSE;
82 }
83
cleanup(void)84 static void cleanup(void)
85 {
86 SAFE_FILE_PRINTF(NULL, PATH_NR_HUGEPAGES, "%ld", orig_hugepages);
87
88 tst_rmdir();
89 }
90
read_hugepagesize(void)91 static int read_hugepagesize(void)
92 {
93 FILE *fp;
94 char line[BUFSIZ], buf[BUFSIZ];
95 int val;
96
97 fp = SAFE_FOPEN(cleanup, PATH_MEMINFO, "r");
98 while (fgets(line, BUFSIZ, fp) != NULL) {
99 if (sscanf(line, "%64s %d", buf, &val) == 2)
100 if (strcmp(buf, "Hugepagesize:") == 0) {
101 SAFE_FCLOSE(cleanup, fp);
102 return 1024 * val;
103 }
104 }
105
106 SAFE_FCLOSE(cleanup, fp);
107 tst_brkm(TBROK, NULL, "can't find \"%s\" in %s",
108 "Hugepagesize:", PATH_MEMINFO);
109 }
110
wait_thread1(void * arg LTP_ATTRIBUTE_UNUSED)111 static void *wait_thread1(void *arg LTP_ATTRIBUTE_UNUSED)
112 {
113 futex_wait(futex1, *futex1, &to, 0);
114
115 return NULL;
116 }
117
wait_thread2(void * arg LTP_ATTRIBUTE_UNUSED)118 static void *wait_thread2(void *arg LTP_ATTRIBUTE_UNUSED)
119 {
120 int res;
121
122 res = futex_wait(futex2, *futex2, &to, 0);
123 if (!res)
124 tst_resm(TPASS, "Hi hydra, thread2 awake!");
125 else
126 tst_resm(TFAIL, "Bug: wait_thread2 did not wake after 30 secs.");
127
128 return NULL;
129 }
130
wakeup_thread2(void)131 static void wakeup_thread2(void)
132 {
133 void *addr;
134 int hpsz, pgsz, res;
135 pthread_t th1, th2;
136
137 hpsz = read_hugepagesize();
138 tst_resm(TINFO, "Hugepagesize %i", hpsz);
139
140 /*allocate some shared memory*/
141 addr = mmap(NULL, hpsz, PROT_WRITE | PROT_READ,
142 MAP_SHARED | MAP_ANONYMOUS | MAP_HUGETLB, -1, 0);
143
144 if (addr == MAP_FAILED) {
145 if (errno == ENOMEM) {
146 tst_brkm(TCONF, NULL,
147 "Cannot allocate hugepage, memory too fragmented?");
148 }
149
150 tst_brkm(TBROK | TERRNO, NULL, "Cannot allocate hugepage");
151 }
152
153 pgsz = getpagesize();
154
155 /*apply the first subpage to futex1*/
156 futex1 = addr;
157 *futex1 = 0;
158 /*apply the second subpage to futex2*/
159 futex2 = (futex_t *)((char *)addr + pgsz);
160 *futex2 = 0;
161
162 /*thread1 block on futex1 first,then thread2 block on futex2*/
163 res = pthread_create(&th1, NULL, wait_thread1, NULL);
164 if (res) {
165 tst_brkm(TBROK, NULL, "pthread_create(): %s",
166 tst_strerrno(res));
167 }
168
169 res = pthread_create(&th2, NULL, wait_thread2, NULL);
170 if (res) {
171 tst_brkm(TBROK, NULL, "pthread_create(): %s",
172 tst_strerrno(res));
173 }
174
175 while (wait_for_threads(2))
176 usleep(100);
177
178 futex_wake(futex2, 1, 0);
179
180 res = pthread_join(th2, NULL);
181 if (res)
182 tst_brkm(TBROK, NULL, "pthread_join(): %s", tst_strerrno(res));
183
184 futex_wake(futex1, 1, 0);
185
186 res = pthread_join(th1, NULL);
187 if (res)
188 tst_brkm(TBROK, NULL, "pthread_join(): %s", tst_strerrno(res));
189
190 SAFE_MUNMAP(NULL, addr, hpsz);
191 }
192
main(int argc,char * argv[])193 int main(int argc, char *argv[])
194 {
195 int lc;
196
197 tst_parse_opts(argc, argv, NULL, NULL);
198
199 setup();
200
201 for (lc = 0; TEST_LOOPING(lc); lc++)
202 wakeup_thread2();
203
204 cleanup();
205 tst_exit();
206 }
207