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