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