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// SPDX-License-Identifier: GPL-2.0-or-later
/******************************************************************************
*
* Copyright © International Business Machines Corp., 2006-2008
*
* DESCRIPTION
* This test exercises the futex_wait_requeue_pi() signal handling both
* before and after the requeue. The first should be restarted by the
* kernel. The latter should return EWOULDBLOCK to the waiter.
*
* AUTHORS
* Darren Hart <dvhart@linux.intel.com>
*
* HISTORY
* 2008-May-5: Initial version by Darren Hart <dvhart@linux.intel.com>
*
*****************************************************************************/
#include <errno.h>
#include <getopt.h>
#include <limits.h>
#include <pthread.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "atomic.h"
#include "futextest.h"
#include "../../kselftest_harness.h"
#define DELAY_US 100
futex_t f1 = FUTEX_INITIALIZER;
futex_t f2 = FUTEX_INITIALIZER;
atomic_t requeued = ATOMIC_INITIALIZER;
int waiter_ret = 0;
int create_rt_thread(pthread_t *pth, void*(*func)(void *), void *arg,
int policy, int prio)
{
struct sched_param schedp;
pthread_attr_t attr;
int ret;
pthread_attr_init(&attr);
memset(&schedp, 0, sizeof(schedp));
ret = pthread_attr_setinheritsched(&attr, PTHREAD_EXPLICIT_SCHED);
if (ret)
ksft_exit_fail_msg("pthread_attr_setinheritsched\n");
ret = pthread_attr_setschedpolicy(&attr, policy);
if (ret)
ksft_exit_fail_msg("pthread_attr_setschedpolicy\n");
schedp.sched_priority = prio;
ret = pthread_attr_setschedparam(&attr, &schedp);
if (ret)
ksft_exit_fail_msg("pthread_attr_setschedparam\n");
ret = pthread_create(pth, &attr, func, arg);
if (ret)
ksft_exit_fail_msg("pthread_create\n");
return 0;
}
void handle_signal(int signo)
{
ksft_print_dbg_msg("signal received %s requeue\n",
requeued.val ? "after" : "prior to");
}
void *waiterfn(void *arg)
{
unsigned int old_val;
int res;
ksft_print_dbg_msg("Waiter running\n");
ksft_print_dbg_msg("Calling FUTEX_LOCK_PI on f2=%x @ %p\n", f2, &f2);
old_val = f1;
res = futex_wait_requeue_pi(&f1, old_val, &(f2), NULL,
FUTEX_PRIVATE_FLAG);
if (!requeued.val || errno != EWOULDBLOCK) {
ksft_test_result_fail("unexpected return from futex_wait_requeue_pi: %d (%s)\n",
res, strerror(errno));
ksft_print_dbg_msg("w2:futex: %x\n", f2);
if (!res)
futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
}
pthread_exit(NULL);
}
TEST(futex_requeue_pi_signal_restart)
{
unsigned int old_val;
struct sigaction sa;
pthread_t waiter;
int res;
sa.sa_handler = handle_signal;
sigemptyset(&sa.sa_mask);
sa.sa_flags = 0;
if (sigaction(SIGUSR1, &sa, NULL))
ksft_exit_fail_msg("sigaction\n");
ksft_print_dbg_msg("m1:f2: %x\n", f2);
ksft_print_dbg_msg("Creating waiter\n");
res = create_rt_thread(&waiter, waiterfn, NULL, SCHED_FIFO, 1);
if (res)
ksft_exit_fail_msg("Creating waiting thread failed");
ksft_print_dbg_msg("Calling FUTEX_LOCK_PI on f2=%x @ %p\n", f2, &f2);
ksft_print_dbg_msg("m2:f2: %x\n", f2);
futex_lock_pi(&f2, 0, 0, FUTEX_PRIVATE_FLAG);
ksft_print_dbg_msg("m3:f2: %x\n", f2);
while (1) {
/*
* signal the waiter before requeue, waiter should automatically
* restart futex_wait_requeue_pi() in the kernel. Wait for the
* waiter to block on f1 again.
*/
ksft_print_dbg_msg("Issuing SIGUSR1 to waiter\n");
pthread_kill(waiter, SIGUSR1);
usleep(DELAY_US);
ksft_print_dbg_msg("Requeueing waiter via FUTEX_CMP_REQUEUE_PI\n");
old_val = f1;
res = futex_cmp_requeue_pi(&f1, old_val, &(f2), 1, 0,
FUTEX_PRIVATE_FLAG);
/*
* If res is non-zero, we either requeued the waiter or hit an
* error, break out and handle it. If it is zero, then the
* signal may have hit before the waiter was blocked on f1.
* Try again.
*/
if (res > 0) {
atomic_set(&requeued, 1);
break;
} else if (res < 0) {
ksft_exit_fail_msg("FUTEX_CMP_REQUEUE_PI failed\n");
}
}
ksft_print_dbg_msg("m4:f2: %x\n", f2);
/*
* Signal the waiter after requeue, waiter should return from
* futex_wait_requeue_pi() with EWOULDBLOCK. Join the thread here so the
* futex_unlock_pi() can't happen before the signal wakeup is detected
* in the kernel.
*/
ksft_print_dbg_msg("Issuing SIGUSR1 to waiter\n");
pthread_kill(waiter, SIGUSR1);
ksft_print_dbg_msg("Waiting for waiter to return\n");
pthread_join(waiter, NULL);
ksft_print_dbg_msg("Calling FUTEX_UNLOCK_PI on mutex=%x @ %p\n", f2, &f2);
futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
ksft_print_dbg_msg("m5:f2: %x\n", f2);
}
TEST_HARNESS_MAIN
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