1 /* 2 * Copyright (C) 2015 Yi Zhang <wetpzy (at) gmail.com> 3 * Li Wang <liwang (at) 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 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 84 static void cleanup(void) 85 { 86 SAFE_FILE_PRINTF(NULL, PATH_NR_HUGEPAGES, "%ld", orig_hugepages); 87 88 tst_rmdir(); 89 } 90 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 } 110 111 static void *wait_thread1(void *arg LTP_ATTRIBUTE_UNUSED) 112 { 113 futex_wait(futex1, *futex1, &to, 0); 114 115 return NULL; 116 } 117 118 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 } 130 131 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 } 192 193 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
