// SPDX-License-Identifier: GPL-2.0-or-later
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/******************************************************************************
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*
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* Copyright © International Business Machines Corp., 2006-2008
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*
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* DESCRIPTION
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* This test exercises the futex_wait_requeue_pi() signal handling both
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* before and after the requeue. The first should be restarted by the
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* kernel. The latter should return EWOULDBLOCK to the waiter.
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*
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* AUTHORS
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* Darren Hart <dvhart@linux.intel.com>
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*
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* HISTORY
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* 2008-May-5: Initial version by Darren Hart <dvhart@linux.intel.com>
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*
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*****************************************************************************/
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#include <errno.h>
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#include <getopt.h>
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#include <limits.h>
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#include <pthread.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "atomic.h"
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#include "futextest.h"
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#include "logging.h"
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#define TEST_NAME "futex-requeue-pi-signal-restart"
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#define DELAY_US 100
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futex_t f1 = FUTEX_INITIALIZER;
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futex_t f2 = FUTEX_INITIALIZER;
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atomic_t requeued = ATOMIC_INITIALIZER;
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int waiter_ret = 0;
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void usage(char *prog)
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{
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printf("Usage: %s\n", prog);
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printf(" -c Use color\n");
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printf(" -h Display this help message\n");
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printf(" -v L Verbosity level: %d=QUIET %d=CRITICAL %d=INFO\n",
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VQUIET, VCRITICAL, VINFO);
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}
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int create_rt_thread(pthread_t *pth, void*(*func)(void *), void *arg,
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int policy, int prio)
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{
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struct sched_param schedp;
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pthread_attr_t attr;
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int ret;
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pthread_attr_init(&attr);
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memset(&schedp, 0, sizeof(schedp));
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ret = pthread_attr_setinheritsched(&attr, PTHREAD_EXPLICIT_SCHED);
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if (ret) {
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error("pthread_attr_setinheritsched\n", ret);
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return -1;
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}
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ret = pthread_attr_setschedpolicy(&attr, policy);
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if (ret) {
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error("pthread_attr_setschedpolicy\n", ret);
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return -1;
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}
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schedp.sched_priority = prio;
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ret = pthread_attr_setschedparam(&attr, &schedp);
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if (ret) {
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error("pthread_attr_setschedparam\n", ret);
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return -1;
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}
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ret = pthread_create(pth, &attr, func, arg);
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if (ret) {
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error("pthread_create\n", ret);
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return -1;
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}
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return 0;
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}
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void handle_signal(int signo)
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{
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info("signal received %s requeue\n",
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requeued.val ? "after" : "prior to");
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}
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void *waiterfn(void *arg)
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{
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unsigned int old_val;
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int res;
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waiter_ret = RET_PASS;
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info("Waiter running\n");
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info("Calling FUTEX_LOCK_PI on f2=%x @ %p\n", f2, &f2);
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old_val = f1;
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res = futex_wait_requeue_pi(&f1, old_val, &(f2), NULL,
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FUTEX_PRIVATE_FLAG);
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if (!requeued.val || errno != EWOULDBLOCK) {
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fail("unexpected return from futex_wait_requeue_pi: %d (%s)\n",
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res, strerror(errno));
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info("w2:futex: %x\n", f2);
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if (!res)
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futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
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waiter_ret = RET_FAIL;
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}
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info("Waiter exiting with %d\n", waiter_ret);
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pthread_exit(NULL);
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}
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int main(int argc, char *argv[])
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{
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unsigned int old_val;
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struct sigaction sa;
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pthread_t waiter;
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int c, res, ret = RET_PASS;
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while ((c = getopt(argc, argv, "chv:")) != -1) {
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switch (c) {
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case 'c':
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log_color(1);
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break;
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case 'h':
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usage(basename(argv[0]));
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exit(0);
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case 'v':
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log_verbosity(atoi(optarg));
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break;
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default:
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usage(basename(argv[0]));
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exit(1);
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}
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}
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ksft_print_header();
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ksft_set_plan(1);
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ksft_print_msg("%s: Test signal handling during requeue_pi\n",
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basename(argv[0]));
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ksft_print_msg("\tArguments: <none>\n");
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sa.sa_handler = handle_signal;
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sigemptyset(&sa.sa_mask);
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sa.sa_flags = 0;
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if (sigaction(SIGUSR1, &sa, NULL)) {
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error("sigaction\n", errno);
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exit(1);
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}
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info("m1:f2: %x\n", f2);
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info("Creating waiter\n");
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res = create_rt_thread(&waiter, waiterfn, NULL, SCHED_FIFO, 1);
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if (res) {
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error("Creating waiting thread failed", res);
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ret = RET_ERROR;
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goto out;
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}
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info("Calling FUTEX_LOCK_PI on f2=%x @ %p\n", f2, &f2);
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info("m2:f2: %x\n", f2);
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futex_lock_pi(&f2, 0, 0, FUTEX_PRIVATE_FLAG);
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info("m3:f2: %x\n", f2);
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while (1) {
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/*
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* signal the waiter before requeue, waiter should automatically
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* restart futex_wait_requeue_pi() in the kernel. Wait for the
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* waiter to block on f1 again.
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*/
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info("Issuing SIGUSR1 to waiter\n");
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pthread_kill(waiter, SIGUSR1);
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usleep(DELAY_US);
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info("Requeueing waiter via FUTEX_CMP_REQUEUE_PI\n");
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old_val = f1;
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res = futex_cmp_requeue_pi(&f1, old_val, &(f2), 1, 0,
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FUTEX_PRIVATE_FLAG);
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/*
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* If res is non-zero, we either requeued the waiter or hit an
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* error, break out and handle it. If it is zero, then the
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* signal may have hit before the the waiter was blocked on f1.
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* Try again.
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*/
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if (res > 0) {
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atomic_set(&requeued, 1);
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break;
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} else if (res < 0) {
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error("FUTEX_CMP_REQUEUE_PI failed\n", errno);
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ret = RET_ERROR;
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break;
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}
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}
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info("m4:f2: %x\n", f2);
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/*
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* Signal the waiter after requeue, waiter should return from
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* futex_wait_requeue_pi() with EWOULDBLOCK. Join the thread here so the
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* futex_unlock_pi() can't happen before the signal wakeup is detected
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* in the kernel.
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*/
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info("Issuing SIGUSR1 to waiter\n");
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pthread_kill(waiter, SIGUSR1);
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info("Waiting for waiter to return\n");
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pthread_join(waiter, NULL);
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info("Calling FUTEX_UNLOCK_PI on mutex=%x @ %p\n", f2, &f2);
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futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
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info("m5:f2: %x\n", f2);
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out:
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if (ret == RET_PASS && waiter_ret)
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ret = waiter_ret;
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print_result(TEST_NAME, ret);
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return ret;
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}
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