1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /****************************************************************************** 3 * 4 * Copyright © International Business Machines Corp., 2009 5 * 6 * DESCRIPTION 7 * Block on a futex and wait for timeout. 8 * 9 * AUTHOR 10 * Darren Hart <dvhart@linux.intel.com> 11 * 12 * HISTORY 13 * 2009-Nov-6: Initial version by Darren Hart <dvhart@linux.intel.com> 14 * 2021-Apr-26: More test cases by André Almeida <andrealmeid@collabora.com> 15 * 16 *****************************************************************************/ 17 18 #include <pthread.h> 19 #include "futextest.h" 20 #include "logging.h" 21 22 #define TEST_NAME "futex-wait-timeout" 23 24 static long timeout_ns = 100000; /* 100us default timeout */ 25 static futex_t futex_pi; 26 27 void usage(char *prog) 28 { 29 printf("Usage: %s\n", prog); 30 printf(" -c Use color\n"); 31 printf(" -h Display this help message\n"); 32 printf(" -t N Timeout in nanoseconds (default: 100,000)\n"); 33 printf(" -v L Verbosity level: %d=QUIET %d=CRITICAL %d=INFO\n", 34 VQUIET, VCRITICAL, VINFO); 35 } 36 37 /* 38 * Get a PI lock and hold it forever, so the main thread lock_pi will block 39 * and we can test the timeout 40 */ 41 void *get_pi_lock(void *arg) 42 { 43 int ret; 44 volatile futex_t lock = 0; 45 46 ret = futex_lock_pi(&futex_pi, NULL, 0, 0); 47 if (ret != 0) 48 error("futex_lock_pi failed\n", ret); 49 50 /* Blocks forever */ 51 ret = futex_wait(&lock, 0, NULL, 0); 52 error("futex_wait failed\n", ret); 53 54 return NULL; 55 } 56 57 /* 58 * Check if the function returned the expected error 59 */ 60 static void test_timeout(int res, int *ret, char *test_name, int err) 61 { 62 if (!res || errno != err) { 63 ksft_test_result_fail("%s returned %d\n", test_name, 64 res < 0 ? errno : res); 65 *ret = RET_FAIL; 66 } else { 67 ksft_test_result_pass("%s succeeds\n", test_name); 68 } 69 } 70 71 /* 72 * Calculate absolute timeout and correct overflow 73 */ 74 static int futex_get_abs_timeout(clockid_t clockid, struct timespec *to, 75 long timeout_ns) 76 { 77 if (clock_gettime(clockid, to)) { 78 error("clock_gettime failed\n", errno); 79 return errno; 80 } 81 82 to->tv_nsec += timeout_ns; 83 84 if (to->tv_nsec >= 1000000000) { 85 to->tv_sec++; 86 to->tv_nsec -= 1000000000; 87 } 88 89 return 0; 90 } 91 92 int main(int argc, char *argv[]) 93 { 94 futex_t f1 = FUTEX_INITIALIZER; 95 int res, ret = RET_PASS; 96 struct timespec to; 97 pthread_t thread; 98 int c; 99 100 while ((c = getopt(argc, argv, "cht:v:")) != -1) { 101 switch (c) { 102 case 'c': 103 log_color(1); 104 break; 105 case 'h': 106 usage(basename(argv[0])); 107 exit(0); 108 case 't': 109 timeout_ns = atoi(optarg); 110 break; 111 case 'v': 112 log_verbosity(atoi(optarg)); 113 break; 114 default: 115 usage(basename(argv[0])); 116 exit(1); 117 } 118 } 119 120 ksft_print_header(); 121 ksft_set_plan(7); 122 ksft_print_msg("%s: Block on a futex and wait for timeout\n", 123 basename(argv[0])); 124 ksft_print_msg("\tArguments: timeout=%ldns\n", timeout_ns); 125 126 pthread_create(&thread, NULL, get_pi_lock, NULL); 127 128 /* initialize relative timeout */ 129 to.tv_sec = 0; 130 to.tv_nsec = timeout_ns; 131 132 res = futex_wait(&f1, f1, &to, 0); 133 test_timeout(res, &ret, "futex_wait relative", ETIMEDOUT); 134 135 /* FUTEX_WAIT_BITSET with CLOCK_REALTIME */ 136 if (futex_get_abs_timeout(CLOCK_REALTIME, &to, timeout_ns)) 137 return RET_FAIL; 138 res = futex_wait_bitset(&f1, f1, &to, 1, FUTEX_CLOCK_REALTIME); 139 test_timeout(res, &ret, "futex_wait_bitset realtime", ETIMEDOUT); 140 141 /* FUTEX_WAIT_BITSET with CLOCK_MONOTONIC */ 142 if (futex_get_abs_timeout(CLOCK_MONOTONIC, &to, timeout_ns)) 143 return RET_FAIL; 144 res = futex_wait_bitset(&f1, f1, &to, 1, 0); 145 test_timeout(res, &ret, "futex_wait_bitset monotonic", ETIMEDOUT); 146 147 /* FUTEX_WAIT_REQUEUE_PI with CLOCK_REALTIME */ 148 if (futex_get_abs_timeout(CLOCK_REALTIME, &to, timeout_ns)) 149 return RET_FAIL; 150 res = futex_wait_requeue_pi(&f1, f1, &futex_pi, &to, FUTEX_CLOCK_REALTIME); 151 test_timeout(res, &ret, "futex_wait_requeue_pi realtime", ETIMEDOUT); 152 153 /* FUTEX_WAIT_REQUEUE_PI with CLOCK_MONOTONIC */ 154 if (futex_get_abs_timeout(CLOCK_MONOTONIC, &to, timeout_ns)) 155 return RET_FAIL; 156 res = futex_wait_requeue_pi(&f1, f1, &futex_pi, &to, 0); 157 test_timeout(res, &ret, "futex_wait_requeue_pi monotonic", ETIMEDOUT); 158 159 /* 160 * FUTEX_LOCK_PI with CLOCK_REALTIME 161 * Due to historical reasons, FUTEX_LOCK_PI supports only realtime 162 * clock, but requires the caller to not set CLOCK_REALTIME flag. 163 * 164 * If you call FUTEX_LOCK_PI with a monotonic clock, it'll be 165 * interpreted as a realtime clock, and (unless you mess your machine's 166 * time or your time machine) the monotonic clock value is always 167 * smaller than realtime and the syscall will timeout immediately. 168 */ 169 if (futex_get_abs_timeout(CLOCK_REALTIME, &to, timeout_ns)) 170 return RET_FAIL; 171 res = futex_lock_pi(&futex_pi, &to, 0, 0); 172 test_timeout(res, &ret, "futex_lock_pi realtime", ETIMEDOUT); 173 174 /* Test operations that don't support FUTEX_CLOCK_REALTIME */ 175 res = futex_lock_pi(&futex_pi, NULL, 0, FUTEX_CLOCK_REALTIME); 176 test_timeout(res, &ret, "futex_lock_pi invalid timeout flag", ENOSYS); 177 178 ksft_print_cnts(); 179 return ret; 180 } 181