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1// SPDX-License-Identifier: GPL-2.0-or-later2/******************************************************************************3 *4 * Copyright © International Business Machines Corp., 2006-20085 *6 * DESCRIPTION7 * This test exercises the futex_wait_requeue_pi() signal handling both8 * before and after the requeue. The first should be restarted by the9 * kernel. The latter should return EWOULDBLOCK to the waiter.10 *11 * AUTHORS12 * Darren Hart <dvhart@linux.intel.com>13 *14 * HISTORY15 * 2008-May-5: Initial version by Darren Hart <dvhart@linux.intel.com>16 *17 *****************************************************************************/18 19#include <errno.h>20#include <getopt.h>21#include <limits.h>22#include <pthread.h>23#include <signal.h>24#include <stdio.h>25#include <stdlib.h>26#include <string.h>27#include "atomic.h"28#include "futextest.h"29#include "logging.h"30 31#define TEST_NAME "futex-requeue-pi-signal-restart"32#define DELAY_US 10033 34futex_t f1 = FUTEX_INITIALIZER;35futex_t f2 = FUTEX_INITIALIZER;36atomic_t requeued = ATOMIC_INITIALIZER;37 38int waiter_ret = 0;39 40void usage(char *prog)41{42 printf("Usage: %s\n", prog);43 printf(" -c Use color\n");44 printf(" -h Display this help message\n");45 printf(" -v L Verbosity level: %d=QUIET %d=CRITICAL %d=INFO\n",46 VQUIET, VCRITICAL, VINFO);47}48 49int create_rt_thread(pthread_t *pth, void*(*func)(void *), void *arg,50 int policy, int prio)51{52 struct sched_param schedp;53 pthread_attr_t attr;54 int ret;55 56 pthread_attr_init(&attr);57 memset(&schedp, 0, sizeof(schedp));58 59 ret = pthread_attr_setinheritsched(&attr, PTHREAD_EXPLICIT_SCHED);60 if (ret) {61 error("pthread_attr_setinheritsched\n", ret);62 return -1;63 }64 65 ret = pthread_attr_setschedpolicy(&attr, policy);66 if (ret) {67 error("pthread_attr_setschedpolicy\n", ret);68 return -1;69 }70 71 schedp.sched_priority = prio;72 ret = pthread_attr_setschedparam(&attr, &schedp);73 if (ret) {74 error("pthread_attr_setschedparam\n", ret);75 return -1;76 }77 78 ret = pthread_create(pth, &attr, func, arg);79 if (ret) {80 error("pthread_create\n", ret);81 return -1;82 }83 return 0;84}85 86void handle_signal(int signo)87{88 info("signal received %s requeue\n",89 requeued.val ? "after" : "prior to");90}91 92void *waiterfn(void *arg)93{94 unsigned int old_val;95 int res;96 97 waiter_ret = RET_PASS;98 99 info("Waiter running\n");100 info("Calling FUTEX_LOCK_PI on f2=%x @ %p\n", f2, &f2);101 old_val = f1;102 res = futex_wait_requeue_pi(&f1, old_val, &(f2), NULL,103 FUTEX_PRIVATE_FLAG);104 if (!requeued.val || errno != EWOULDBLOCK) {105 fail("unexpected return from futex_wait_requeue_pi: %d (%s)\n",106 res, strerror(errno));107 info("w2:futex: %x\n", f2);108 if (!res)109 futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);110 waiter_ret = RET_FAIL;111 }112 113 info("Waiter exiting with %d\n", waiter_ret);114 pthread_exit(NULL);115}116 117 118int main(int argc, char *argv[])119{120 unsigned int old_val;121 struct sigaction sa;122 pthread_t waiter;123 int c, res, ret = RET_PASS;124 125 while ((c = getopt(argc, argv, "chv:")) != -1) {126 switch (c) {127 case 'c':128 log_color(1);129 break;130 case 'h':131 usage(basename(argv[0]));132 exit(0);133 case 'v':134 log_verbosity(atoi(optarg));135 break;136 default:137 usage(basename(argv[0]));138 exit(1);139 }140 }141 142 ksft_print_header();143 ksft_set_plan(1);144 ksft_print_msg("%s: Test signal handling during requeue_pi\n",145 basename(argv[0]));146 ksft_print_msg("\tArguments: <none>\n");147 148 sa.sa_handler = handle_signal;149 sigemptyset(&sa.sa_mask);150 sa.sa_flags = 0;151 if (sigaction(SIGUSR1, &sa, NULL)) {152 error("sigaction\n", errno);153 exit(1);154 }155 156 info("m1:f2: %x\n", f2);157 info("Creating waiter\n");158 res = create_rt_thread(&waiter, waiterfn, NULL, SCHED_FIFO, 1);159 if (res) {160 error("Creating waiting thread failed", res);161 ret = RET_ERROR;162 goto out;163 }164 165 info("Calling FUTEX_LOCK_PI on f2=%x @ %p\n", f2, &f2);166 info("m2:f2: %x\n", f2);167 futex_lock_pi(&f2, 0, 0, FUTEX_PRIVATE_FLAG);168 info("m3:f2: %x\n", f2);169 170 while (1) {171 /*172 * signal the waiter before requeue, waiter should automatically173 * restart futex_wait_requeue_pi() in the kernel. Wait for the174 * waiter to block on f1 again.175 */176 info("Issuing SIGUSR1 to waiter\n");177 pthread_kill(waiter, SIGUSR1);178 usleep(DELAY_US);179 180 info("Requeueing waiter via FUTEX_CMP_REQUEUE_PI\n");181 old_val = f1;182 res = futex_cmp_requeue_pi(&f1, old_val, &(f2), 1, 0,183 FUTEX_PRIVATE_FLAG);184 /*185 * If res is non-zero, we either requeued the waiter or hit an186 * error, break out and handle it. If it is zero, then the187 * signal may have hit before the waiter was blocked on f1.188 * Try again.189 */190 if (res > 0) {191 atomic_set(&requeued, 1);192 break;193 } else if (res < 0) {194 error("FUTEX_CMP_REQUEUE_PI failed\n", errno);195 ret = RET_ERROR;196 break;197 }198 }199 info("m4:f2: %x\n", f2);200 201 /*202 * Signal the waiter after requeue, waiter should return from203 * futex_wait_requeue_pi() with EWOULDBLOCK. Join the thread here so the204 * futex_unlock_pi() can't happen before the signal wakeup is detected205 * in the kernel.206 */207 info("Issuing SIGUSR1 to waiter\n");208 pthread_kill(waiter, SIGUSR1);209 info("Waiting for waiter to return\n");210 pthread_join(waiter, NULL);211 212 info("Calling FUTEX_UNLOCK_PI on mutex=%x @ %p\n", f2, &f2);213 futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);214 info("m5:f2: %x\n", f2);215 216 out:217 if (ret == RET_PASS && waiter_ret)218 ret = waiter_ret;219 220 print_result(TEST_NAME, ret);221 return ret;222}223