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

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/******************************************************************************
   3 *
   4 * Copyright FUJITSU LIMITED 2010
   5 * Copyright KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
   6 *
   7 * DESCRIPTION
   8 *      Wait on uninitialized heap. It shold be zero and FUTEX_WAIT should
   9 *      return immediately. This test is intent to test zero page handling in
  10 *      futex.
  11 *
  12 * AUTHOR
  13 *      KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
  14 *
  15 * HISTORY
  16 *      2010-Jan-6: Initial version by KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
  17 *
  18 *****************************************************************************/
  19
  20#include <pthread.h>
  21#include <stdio.h>
  22#include <stdlib.h>
  23#include <sys/mman.h>
  24#include <syscall.h>
  25#include <sys/types.h>
  26#include <sys/stat.h>
  27#include <unistd.h>
  28#include <errno.h>
  29#include <linux/futex.h>
  30#include <libgen.h>
  31
  32#include "logging.h"
  33#include "futextest.h"
  34
  35#define TEST_NAME "futex-wait-uninitialized-heap"
  36#define WAIT_US 5000000
  37
  38static int child_blocked = 1;
  39static int child_ret;
  40void *buf;
  41
  42void usage(char *prog)
  43{
  44        printf("Usage: %s\n", prog);
  45        printf("  -c    Use color\n");
  46        printf("  -h    Display this help message\n");
  47        printf("  -v L  Verbosity level: %d=QUIET %d=CRITICAL %d=INFO\n",
  48               VQUIET, VCRITICAL, VINFO);
  49}
  50
  51void *wait_thread(void *arg)
  52{
  53        int res;
  54
  55        child_ret = RET_PASS;
  56        res = futex_wait(buf, 1, NULL, 0);
  57        child_blocked = 0;
  58
  59        if (res != 0 && errno != EWOULDBLOCK) {
  60                error("futex failure\n", errno);
  61                child_ret = RET_ERROR;
  62        }
  63        pthread_exit(NULL);
  64}
  65
  66int main(int argc, char **argv)
  67{
  68        int c, ret = RET_PASS;
  69        long page_size;
  70        pthread_t thr;
  71
  72        while ((c = getopt(argc, argv, "chv:")) != -1) {
  73                switch (c) {
  74                case 'c':
  75                        log_color(1);
  76                        break;
  77                case 'h':
  78                        usage(basename(argv[0]));
  79                        exit(0);
  80                case 'v':
  81                        log_verbosity(atoi(optarg));
  82                        break;
  83                default:
  84                        usage(basename(argv[0]));
  85                        exit(1);
  86                }
  87        }
  88
  89        page_size = sysconf(_SC_PAGESIZE);
  90
  91        buf = mmap(NULL, page_size, PROT_READ|PROT_WRITE,
  92                   MAP_PRIVATE|MAP_ANONYMOUS, 0, 0);
  93        if (buf == (void *)-1) {
  94                error("mmap\n", errno);
  95                exit(1);
  96        }
  97
  98        ksft_print_header();
  99        ksft_set_plan(1);
 100        ksft_print_msg("%s: Test the uninitialized futex value in FUTEX_WAIT\n",
 101               basename(argv[0]));
 102
 103
 104        ret = pthread_create(&thr, NULL, wait_thread, NULL);
 105        if (ret) {
 106                error("pthread_create\n", errno);
 107                ret = RET_ERROR;
 108                goto out;
 109        }
 110
 111        info("waiting %dus for child to return\n", WAIT_US);
 112        usleep(WAIT_US);
 113
 114        ret = child_ret;
 115        if (child_blocked) {
 116                fail("child blocked in kernel\n");
 117                ret = RET_FAIL;
 118        }
 119
 120 out:
 121        print_result(TEST_NAME, ret);
 122        return ret;
 123}
 124