void *waiterfn(void *arg)
{
struct thread_arg *args = (struct thread_arg *)arg;
futex_t old_val;
info("Waiter %ld: running\n", args->id);
/* Each thread sleeps for a different amount of time
* This is to avoid races, because we don't lock the
* external mutex here */
usleep(1000 * (long)args->id);
old_val = f1;
atomic_inc(&waiters_blocked);
info("Calling futex_wait_requeue_pi: %p (%u) -> %p\n",
&f1, f1, &f2);
args->ret = futex_wait_requeue_pi(&f1, old_val, &f2, args->timeout,
FUTEX_PRIVATE_FLAG);
info("waiter %ld woke with %d %s\n", args->id, args->ret,
args->ret < 0 ? strerror(errno) : "");
atomic_inc(&waiters_woken);
if (args->ret < 0) {
if (args->timeout && errno == ETIMEDOUT)
args->ret = 0;
else {
args->ret = RET_ERROR;
error("futex_wait_requeue_pi\n", errno);
}
futex_lock_pi(&f2, NULL, 0, FUTEX_PRIVATE_FLAG);
}
futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
info("Waiter %ld: exiting with %d\n", args->id, args->ret);
pthread_exit((void *)&args->ret);
}
void *broadcast_wakerfn(void *arg)
{
struct thread_arg *args = (struct thread_arg *)arg;
int nr_requeue = INT_MAX;
int task_count = 0;
futex_t old_val;
int nr_wake = 1;
int i = 0;
info("Waker: waiting for waiters to block\n");
while (waiters_blocked.val < THREAD_MAX)
usleep(1000);
usleep(1000);
info("Waker: Calling broadcast\n");
if (args->lock) {
info("Calling FUTEX_LOCK_PI on mutex=%x @ %p\n", f2, &f2);
futex_lock_pi(&f2, NULL, 0, FUTEX_PRIVATE_FLAG);
}
continue_requeue:
old_val = f1;
args->ret = futex_cmp_requeue_pi(&f1, old_val, &f2, nr_wake, nr_requeue,
FUTEX_PRIVATE_FLAG);
if (args->ret < 0) {
args->ret = RET_ERROR;
error("FUTEX_CMP_REQUEUE_PI failed\n", errno);
} else if (++i < MAX_WAKE_ITERS) {
task_count += args->ret;
if (task_count < THREAD_MAX - waiters_woken.val)
goto continue_requeue;
} else {
error("max broadcast iterations (%d) reached with %d/%d tasks woken or requeued\n",
0, MAX_WAKE_ITERS, task_count, THREAD_MAX);
args->ret = RET_ERROR;
}
futex_wake(&wake_complete, 1, FUTEX_PRIVATE_FLAG);
if (args->lock)
futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
if (args->ret > 0)
args->ret = task_count;
info("Waker: exiting with %d\n", args->ret);
pthread_exit((void *)&args->ret);
}
void *third_party_blocker(void *arg)
{
struct thread_arg *args = (struct thread_arg *)arg;
int ret2 = 0;
args->ret = futex_lock_pi(&f2, NULL, 0, FUTEX_PRIVATE_FLAG);
if (args->ret)
goto out;
args->ret = futex_wait(&wake_complete, wake_complete, NULL,
FUTEX_PRIVATE_FLAG);
ret2 = futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
out:
if (args->ret || ret2) {
error("third_party_blocker() futex error", 0);
args->ret = RET_ERROR;
}
pthread_exit((void *)&args->ret);
}
void *waiterfn(void *arg)
{
unsigned int old_val;
int res;
waiter_ret = RET_PASS;
info("Waiter running\n");
info("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) {
fail("unexpected return from futex_wait_requeue_pi: %d (%s)\n",
res, strerror(errno));
info("w2:futex: %x\n", f2);
if (!res)
futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
waiter_ret = RET_FAIL;
}
info("Waiter exiting with %d\n", waiter_ret);
pthread_exit(NULL);
}
int main(int argc, char *argv[])
{
unsigned int old_val;
struct sigaction sa;
pthread_t waiter;
int c, res, ret = RET_PASS;
while ((c = getopt(argc, argv, "chv:")) != -1) {
switch (c) {
case 'c':
log_color(1);
break;
case 'h':
usage(basename(argv[0]));
exit(0);
case 'v':
log_verbosity(atoi(optarg));
break;
default:
usage(basename(argv[0]));
exit(1);
}
}
ksft_print_header();
ksft_set_plan(1);
ksft_print_msg("%s: Test signal handling during requeue_pi\n",
basename(argv[0]));
ksft_print_msg("\tArguments: <none>\n");
sa.sa_handler = handle_signal;
sigemptyset(&sa.sa_mask);
sa.sa_flags = 0;
if (sigaction(SIGUSR1, &sa, NULL)) {
error("sigaction\n", errno);
exit(1);
}
info("m1:f2: %x\n", f2);
info("Creating waiter\n");
res = create_rt_thread(&waiter, waiterfn, NULL, SCHED_FIFO, 1);
if (res) {
error("Creating waiting thread failed", res);
ret = RET_ERROR;
goto out;
}
info("Calling FUTEX_LOCK_PI on f2=%x @ %p\n", f2, &f2);
info("m2:f2: %x\n", f2);
futex_lock_pi(&f2, 0, 0, FUTEX_PRIVATE_FLAG);
info("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.
*/
info("Issuing SIGUSR1 to waiter\n");
pthread_kill(waiter, SIGUSR1);
usleep(DELAY_US);
info("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 the waiter was blocked on f1.
* Try again.
*/
if (res > 0) {
atomic_set(&requeued, 1);
break;
} else if (res < 0) {
error("FUTEX_CMP_REQUEUE_PI failed\n", errno);
ret = RET_ERROR;
break;
}
}
info("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.
*/
info("Issuing SIGUSR1 to waiter\n");
pthread_kill(waiter, SIGUSR1);
info("Waiting for waiter to return\n");
pthread_join(waiter, NULL);
info("Calling FUTEX_UNLOCK_PI on mutex=%x @ %p\n", f2, &f2);
futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
info("m5:f2: %x\n", f2);
out:
if (ret == RET_PASS && waiter_ret)
ret = waiter_ret;
print_result(TEST_NAME, ret);
return ret;
}
void *signal_wakerfn(void *arg)
{
struct thread_arg *args = (struct thread_arg *)arg;
unsigned int old_val;
int nr_requeue = 0;
int task_count = 0;
int nr_wake = 1;
int i = 0;
info("Waker: waiting for waiters to block\n");
while (waiters_blocked.val < THREAD_MAX)
usleep(1000);
usleep(1000);
while (task_count < THREAD_MAX && waiters_woken.val < THREAD_MAX) {
info("task_count: %d, waiters_woken: %d\n",
task_count, waiters_woken.val);
if (args->lock) {
info("Calling FUTEX_LOCK_PI on mutex=%x @ %p\n",
f2, &f2);
futex_lock_pi(&f2, NULL, 0, FUTEX_PRIVATE_FLAG);
}
info("Waker: Calling signal\n");
/* cond_signal */
old_val = f1;
args->ret = futex_cmp_requeue_pi(&f1, old_val, &f2,
nr_wake, nr_requeue,
FUTEX_PRIVATE_FLAG);
if (args->ret < 0)
args->ret = -errno;
info("futex: %x\n", f2);
if (args->lock) {
info("Calling FUTEX_UNLOCK_PI on mutex=%x @ %p\n",
f2, &f2);
futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
}
info("futex: %x\n", f2);
if (args->ret < 0) {
error("FUTEX_CMP_REQUEUE_PI failed\n", errno);
args->ret = RET_ERROR;
break;
}
task_count += args->ret;
usleep(SIGNAL_PERIOD_US);
i++;
/* we have to loop at least THREAD_MAX times */
if (i > MAX_WAKE_ITERS + THREAD_MAX) {
error("max signaling iterations (%d) reached, giving up on pending waiters.\n",
0, MAX_WAKE_ITERS + THREAD_MAX);
args->ret = RET_ERROR;
break;
}
}
futex_wake(&wake_complete, 1, FUTEX_PRIVATE_FLAG);
if (args->ret >= 0)
args->ret = task_count;
info("Waker: exiting with %d\n", args->ret);
info("Waker: waiters_woken: %d\n", waiters_woken.val);
pthread_exit((void *)&args->ret);
}
