/******************************************************************************
*
* Copyright © International Business Machines Corp., 2009
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* DESCRIPTION
* 1. Block a thread using FUTEX_WAIT
* 2. Attempt to use FUTEX_CMP_REQUEUE_PI on the futex from 1.
* 3. The kernel must detect the mismatch and return -EINVAL.
*
* AUTHOR
* Darren Hart <dvhart@linux.intel.com>
*
* HISTORY
* 2009-Nov-9: Initial version by Darren Hart <dvhart@linux.intel.com>
*
*****************************************************************************/
#include <errno.h>
#include <getopt.h>
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include "futextest.h"
#include "logging.h"
futex_t f1 = FUTEX_INITIALIZER;
futex_t f2 = FUTEX_INITIALIZER;
int child_ret = 0;
void usage(char *prog)
{
printf("Usage: %s\n", prog);
printf(" -c Use color\n");
printf(" -h Display this help message\n");
printf(" -v L Verbosity level: %d=QUIET %d=CRITICAL %d=INFO\n",
VQUIET, VCRITICAL, VINFO);
}
void *blocking_child(void *arg)
{
child_ret = futex_wait(&f1, f1, NULL, FUTEX_PRIVATE_FLAG);
if (child_ret < 0) {
child_ret = -errno;
error("futex_wait\n", errno);
}
return (void *)&child_ret;
}
int main(int argc, char *argv[])
{
int ret = RET_PASS;
pthread_t child;
int c;
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);
}
}
printf("%s: Detect mismatched requeue_pi operations\n",
basename(argv[0]));
if (pthread_create(&child, NULL, blocking_child, NULL)) {
error("pthread_create\n", errno);
ret = RET_ERROR;
goto out;
}
/* Allow the child to block in the kernel. */
sleep(1);
/*
* The kernel should detect the waiter did not setup the
* q->requeue_pi_key and return -EINVAL. If it does not,
* it likely gave the lock to the child, which is now hung
* in the kernel.
*/
ret = futex_cmp_requeue_pi(&f1, f1, &f2, 1, 0, FUTEX_PRIVATE_FLAG);
if (ret < 0) {
if (errno == EINVAL) {
/*
* The kernel correctly detected the mismatched
* requeue_pi target and aborted. Wake the child with
* FUTEX_WAKE.
*/
ret = futex_wake(&f1, 1, FUTEX_PRIVATE_FLAG);
if (ret == 1) {
ret = RET_PASS;
} else if (ret < 0) {
error("futex_wake\n", errno);
ret = RET_ERROR;
} else {
error("futex_wake did not wake the child\n", 0);
ret = RET_ERROR;
}
} else {
error("futex_cmp_requeue_pi\n", errno);
ret = RET_ERROR;
}
} else if (ret > 0) {
fail("futex_cmp_requeue_pi failed to detect the mismatch\n");
ret = RET_FAIL;
} else {
error("futex_cmp_requeue_pi found no waiters\n", 0);
ret = RET_ERROR;
}
pthread_join(child, NULL);
if (!ret)
ret = child_ret;
out:
/* If the kernel crashes, we shouldn't return at all. */
print_result(ret);
return ret;
}
