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(prog: basename(argv[0]));
79 exit(0);
80 case 'v':
81 log_verbosity(atoi(optarg));
82 break;
83 default:
84 usage(prog: 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

source code of linux/tools/testing/selftests/futex/functional/futex_wait_uninitialized_heap.c