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1// SPDX-License-Identifier: GPL-2.0-or-later2/******************************************************************************3 *4 * Copyright © International Business Machines Corp., 20095 *6 * DESCRIPTION7 * Block on a futex and wait for timeout.8 *9 * AUTHOR10 * Darren Hart <dvhart@linux.intel.com>11 *12 * HISTORY13 * 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 "futex2test.h"21#include "logging.h"22 23#define TEST_NAME "futex-wait-timeout"24 25static long timeout_ns = 100000; /* 100us default timeout */26static futex_t futex_pi;27static pthread_barrier_t barrier;28 29void usage(char *prog)30{31 printf("Usage: %s\n", prog);32 printf(" -c Use color\n");33 printf(" -h Display this help message\n");34 printf(" -t N Timeout in nanoseconds (default: 100,000)\n");35 printf(" -v L Verbosity level: %d=QUIET %d=CRITICAL %d=INFO\n",36 VQUIET, VCRITICAL, VINFO);37}38 39/*40 * Get a PI lock and hold it forever, so the main thread lock_pi will block41 * and we can test the timeout42 */43void *get_pi_lock(void *arg)44{45 int ret;46 volatile futex_t lock = 0;47 48 ret = futex_lock_pi(&futex_pi, NULL, 0, 0);49 if (ret != 0)50 error("futex_lock_pi failed\n", ret);51 52 pthread_barrier_wait(&barrier);53 54 /* Blocks forever */55 ret = futex_wait(&lock, 0, NULL, 0);56 error("futex_wait failed\n", ret);57 58 return NULL;59}60 61/*62 * Check if the function returned the expected error63 */64static void test_timeout(int res, int *ret, char *test_name, int err)65{66 if (!res || errno != err) {67 ksft_test_result_fail("%s returned %d\n", test_name,68 res < 0 ? errno : res);69 *ret = RET_FAIL;70 } else {71 ksft_test_result_pass("%s succeeds\n", test_name);72 }73}74 75/*76 * Calculate absolute timeout and correct overflow77 */78static int futex_get_abs_timeout(clockid_t clockid, struct timespec *to,79 long timeout_ns)80{81 if (clock_gettime(clockid, to)) {82 error("clock_gettime failed\n", errno);83 return errno;84 }85 86 to->tv_nsec += timeout_ns;87 88 if (to->tv_nsec >= 1000000000) {89 to->tv_sec++;90 to->tv_nsec -= 1000000000;91 }92 93 return 0;94}95 96int main(int argc, char *argv[])97{98 futex_t f1 = FUTEX_INITIALIZER;99 int res, ret = RET_PASS;100 struct timespec to;101 pthread_t thread;102 int c;103 struct futex_waitv waitv = {104 .uaddr = (uintptr_t)&f1,105 .val = f1,106 .flags = FUTEX_32,107 .__reserved = 0108 };109 110 while ((c = getopt(argc, argv, "cht:v:")) != -1) {111 switch (c) {112 case 'c':113 log_color(1);114 break;115 case 'h':116 usage(basename(argv[0]));117 exit(0);118 case 't':119 timeout_ns = atoi(optarg);120 break;121 case 'v':122 log_verbosity(atoi(optarg));123 break;124 default:125 usage(basename(argv[0]));126 exit(1);127 }128 }129 130 ksft_print_header();131 ksft_set_plan(9);132 ksft_print_msg("%s: Block on a futex and wait for timeout\n",133 basename(argv[0]));134 ksft_print_msg("\tArguments: timeout=%ldns\n", timeout_ns);135 136 pthread_barrier_init(&barrier, NULL, 2);137 pthread_create(&thread, NULL, get_pi_lock, NULL);138 139 /* initialize relative timeout */140 to.tv_sec = 0;141 to.tv_nsec = timeout_ns;142 143 res = futex_wait(&f1, f1, &to, 0);144 test_timeout(res, &ret, "futex_wait relative", ETIMEDOUT);145 146 /* FUTEX_WAIT_BITSET with CLOCK_REALTIME */147 if (futex_get_abs_timeout(CLOCK_REALTIME, &to, timeout_ns))148 return RET_FAIL;149 res = futex_wait_bitset(&f1, f1, &to, 1, FUTEX_CLOCK_REALTIME);150 test_timeout(res, &ret, "futex_wait_bitset realtime", ETIMEDOUT);151 152 /* FUTEX_WAIT_BITSET with CLOCK_MONOTONIC */153 if (futex_get_abs_timeout(CLOCK_MONOTONIC, &to, timeout_ns))154 return RET_FAIL;155 res = futex_wait_bitset(&f1, f1, &to, 1, 0);156 test_timeout(res, &ret, "futex_wait_bitset monotonic", ETIMEDOUT);157 158 /* FUTEX_WAIT_REQUEUE_PI with CLOCK_REALTIME */159 if (futex_get_abs_timeout(CLOCK_REALTIME, &to, timeout_ns))160 return RET_FAIL;161 res = futex_wait_requeue_pi(&f1, f1, &futex_pi, &to, FUTEX_CLOCK_REALTIME);162 test_timeout(res, &ret, "futex_wait_requeue_pi realtime", ETIMEDOUT);163 164 /* FUTEX_WAIT_REQUEUE_PI with CLOCK_MONOTONIC */165 if (futex_get_abs_timeout(CLOCK_MONOTONIC, &to, timeout_ns))166 return RET_FAIL;167 res = futex_wait_requeue_pi(&f1, f1, &futex_pi, &to, 0);168 test_timeout(res, &ret, "futex_wait_requeue_pi monotonic", ETIMEDOUT);169 170 /* Wait until the other thread calls futex_lock_pi() */171 pthread_barrier_wait(&barrier);172 pthread_barrier_destroy(&barrier);173 /*174 * FUTEX_LOCK_PI with CLOCK_REALTIME175 * Due to historical reasons, FUTEX_LOCK_PI supports only realtime176 * clock, but requires the caller to not set CLOCK_REALTIME flag.177 *178 * If you call FUTEX_LOCK_PI with a monotonic clock, it'll be179 * interpreted as a realtime clock, and (unless you mess your machine's180 * time or your time machine) the monotonic clock value is always181 * smaller than realtime and the syscall will timeout immediately.182 */183 if (futex_get_abs_timeout(CLOCK_REALTIME, &to, timeout_ns))184 return RET_FAIL;185 res = futex_lock_pi(&futex_pi, &to, 0, 0);186 test_timeout(res, &ret, "futex_lock_pi realtime", ETIMEDOUT);187 188 /* Test operations that don't support FUTEX_CLOCK_REALTIME */189 res = futex_lock_pi(&futex_pi, NULL, 0, FUTEX_CLOCK_REALTIME);190 test_timeout(res, &ret, "futex_lock_pi invalid timeout flag", ENOSYS);191 192 /* futex_waitv with CLOCK_MONOTONIC */193 if (futex_get_abs_timeout(CLOCK_MONOTONIC, &to, timeout_ns))194 return RET_FAIL;195 res = futex_waitv(&waitv, 1, 0, &to, CLOCK_MONOTONIC);196 test_timeout(res, &ret, "futex_waitv monotonic", ETIMEDOUT);197 198 /* futex_waitv with CLOCK_REALTIME */199 if (futex_get_abs_timeout(CLOCK_REALTIME, &to, timeout_ns))200 return RET_FAIL;201 res = futex_waitv(&waitv, 1, 0, &to, CLOCK_REALTIME);202 test_timeout(res, &ret, "futex_waitv realtime", ETIMEDOUT);203 204 ksft_print_cnts();205 return ret;206}207