LXR linux/tools/testing/selftests/futex/functional/futex_requeue_pi_mismatched

   1/******************************************************************************
   2 *
   3 *   Copyright © International Business Machines  Corp., 2009
   4 *
   5 *   This program is free software;  you can redistribute it and/or modify
   6 *   it under the terms of the GNU General Public License as published by
   7 *   the Free Software Foundation; either version 2 of the License, or
   8 *   (at your option) any later version.
   9 *
  10 * DESCRIPTION
  11 *      1. Block a thread using FUTEX_WAIT
  12 *      2. Attempt to use FUTEX_CMP_REQUEUE_PI on the futex from 1.
  13 *      3. The kernel must detect the mismatch and return -EINVAL.
  14 *
  15 * AUTHOR
  16 *      Darren Hart <dvhart@linux.intel.com>
  17 *
  18 * HISTORY
  19 *      2009-Nov-9: Initial version by Darren Hart <dvhart@linux.intel.com>
  20 *
  21 *****************************************************************************/
  22
  23#include <errno.h>
  24#include <getopt.h>
  25#include <pthread.h>
  26#include <stdio.h>
  27#include <stdlib.h>
  28#include <string.h>
  29#include <time.h>
  30#include "futextest.h"
  31#include "logging.h"
  32
  33#define TEST_NAME "futex-requeue-pi-mismatched-ops"
  34
  35futex_t f1 = FUTEX_INITIALIZER;
  36futex_t f2 = FUTEX_INITIALIZER;
  37int child_ret = 0;
  38
  39void usage(char *prog)
  40{
  41        printf("Usage: %s\n", prog);
  42        printf("  -c    Use color\n");
  43        printf("  -h    Display this help message\n");
  44        printf("  -v L  Verbosity level: %d=QUIET %d=CRITICAL %d=INFO\n",
  45               VQUIET, VCRITICAL, VINFO);
  46}
  47
  48void *blocking_child(void *arg)
  49{
  50        child_ret = futex_wait(&f1, f1, NULL, FUTEX_PRIVATE_FLAG);
  51        if (child_ret < 0) {
  52                child_ret = -errno;
  53                error("futex_wait\n", errno);
  54        }
  55        return (void *)&child_ret;
  56}
  57
  58int main(int argc, char *argv[])
  59{
  60        int ret = RET_PASS;
  61        pthread_t child;
  62        int c;
  63
  64        while ((c = getopt(argc, argv, "chv:")) != -1) {
  65                switch (c) {
  66                case 'c':
  67                        log_color(1);
  68                        break;
  69                case 'h':
  70                        usage(basename(argv[0]));
  71                        exit(0);
  72                case 'v':
  73                        log_verbosity(atoi(optarg));
  74                        break;
  75                default:
  76                        usage(basename(argv[0]));
  77                        exit(1);
  78                }
  79        }
  80
  81        ksft_print_header();
  82        ksft_print_msg("%s: Detect mismatched requeue_pi operations\n",
  83               basename(argv[0]));
  84
  85        if (pthread_create(&child, NULL, blocking_child, NULL)) {
  86                error("pthread_create\n", errno);
  87                ret = RET_ERROR;
  88                goto out;
  89        }
  90        /* Allow the child to block in the kernel. */
  91        sleep(1);
  92
  93        /*
  94         * The kernel should detect the waiter did not setup the
  95         * q->requeue_pi_key and return -EINVAL. If it does not,
  96         * it likely gave the lock to the child, which is now hung
  97         * in the kernel.
  98         */
  99        ret = futex_cmp_requeue_pi(&f1, f1, &f2, 1, 0, FUTEX_PRIVATE_FLAG);
 100        if (ret < 0) {
 101                if (errno == EINVAL) {
 102                        /*
 103                         * The kernel correctly detected the mismatched
 104                         * requeue_pi target and aborted. Wake the child with
 105                         * FUTEX_WAKE.
 106                         */
 107                        ret = futex_wake(&f1, 1, FUTEX_PRIVATE_FLAG);
 108                        if (ret == 1) {
 109                                ret = RET_PASS;
 110                        } else if (ret < 0) {
 111                                error("futex_wake\n", errno);
 112                                ret = RET_ERROR;
 113                        } else {
 114                                error("futex_wake did not wake the child\n", 0);
 115                                ret = RET_ERROR;
 116                        }
 117                } else {
 118                        error("futex_cmp_requeue_pi\n", errno);
 119                        ret = RET_ERROR;
 120                }
 121        } else if (ret > 0) {
 122                fail("futex_cmp_requeue_pi failed to detect the mismatch\n");
 123                ret = RET_FAIL;
 124        } else {
 125                error("futex_cmp_requeue_pi found no waiters\n", 0);
 126                ret = RET_ERROR;
 127        }
 128
 129        pthread_join(child, NULL);
 130
 131        if (!ret)
 132                ret = child_ret;
 133
 134 out:
 135        /* If the kernel crashes, we shouldn't return at all. */
 136        print_result(TEST_NAME, ret);
 137        return ret;
 138}
 139