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
  33futex_t f1 = FUTEX_INITIALIZER;
  34futex_t f2 = FUTEX_INITIALIZER;
  35int child_ret = 0;
  36
  37void usage(char *prog)
  38{
  39        printf("Usage: %s\n", prog);
  40        printf("  -c    Use color\n");
  41        printf("  -h    Display this help message\n");
  42        printf("  -v L  Verbosity level: %d=QUIET %d=CRITICAL %d=INFO\n",
  43               VQUIET, VCRITICAL, VINFO);
  44}
  45
  46void *blocking_child(void *arg)
  47{
  48        child_ret = futex_wait(&f1, f1, NULL, FUTEX_PRIVATE_FLAG);
  49        if (child_ret < 0) {
  50                child_ret = -errno;
  51                error("futex_wait\n", errno);
  52        }
  53        return (void *)&child_ret;
  54}
  55
  56int main(int argc, char *argv[])
  57{
  58        int ret = RET_PASS;
  59        pthread_t child;
  60        int c;
  61
  62        while ((c = getopt(argc, argv, "chv:")) != -1) {
  63                switch (c) {
  64                case 'c':
  65                        log_color(1);
  66                        break;
  67                case 'h':
  68                        usage(basename(argv[0]));
  69                        exit(0);
  70                case 'v':
  71                        log_verbosity(atoi(optarg));
  72                        break;
  73                default:
  74                        usage(basename(argv[0]));
  75                        exit(1);
  76                }
  77        }
  78
  79        printf("%s: Detect mismatched requeue_pi operations\n",
  80               basename(argv[0]));
  81
  82        if (pthread_create(&child, NULL, blocking_child, NULL)) {
  83                error("pthread_create\n", errno);
  84                ret = RET_ERROR;
  85                goto out;
  86        }
  87        /* Allow the child to block in the kernel. */
  88        sleep(1);
  89
  90        /*
  91         * The kernel should detect the waiter did not setup the
  92         * q->requeue_pi_key and return -EINVAL. If it does not,
  93         * it likely gave the lock to the child, which is now hung
  94         * in the kernel.
  95         */
  96        ret = futex_cmp_requeue_pi(&f1, f1, &f2, 1, 0, FUTEX_PRIVATE_FLAG);
  97        if (ret < 0) {
  98                if (errno == EINVAL) {
  99                        /*
 100                         * The kernel correctly detected the mismatched
 101                         * requeue_pi target and aborted. Wake the child with
 102                         * FUTEX_WAKE.
 103                         */
 104                        ret = futex_wake(&f1, 1, FUTEX_PRIVATE_FLAG);
 105                        if (ret == 1) {
 106                                ret = RET_PASS;
 107                        } else if (ret < 0) {
 108                                error("futex_wake\n", errno);
 109                                ret = RET_ERROR;
 110                        } else {
 111                                error("futex_wake did not wake the child\n", 0);
 112                                ret = RET_ERROR;
 113                        }
 114                } else {
 115                        error("futex_cmp_requeue_pi\n", errno);
 116                        ret = RET_ERROR;
 117                }
 118        } else if (ret > 0) {
 119                fail("futex_cmp_requeue_pi failed to detect the mismatch\n");
 120                ret = RET_FAIL;
 121        } else {
 122                error("futex_cmp_requeue_pi found no waiters\n", 0);
 123                ret = RET_ERROR;
 124        }
 125
 126        pthread_join(child, NULL);
 127
 128        if (!ret)
 129                ret = child_ret;
 130
 131 out:
 132        /* If the kernel crashes, we shouldn't return at all. */
 133        print_result(ret);
 134        return ret;
 135}
 136