1// SPDX-License-Identifier: GPL-2.0-or-later
2/******************************************************************************
3 *
4 *   Copyright �� International Business Machines  Corp., 2009
5 *
6 * DESCRIPTION
7 *      1. Block a thread using FUTEX_WAIT
8 *      2. Attempt to use FUTEX_CMP_REQUEUE_PI on the futex from 1.
9 *      3. The kernel must detect the mismatch and return -EINVAL.
10 *
11 * AUTHOR
12 *      Darren Hart <dvhart@linux.intel.com>
13 *
14 * HISTORY
15 *      2009-Nov-9: Initial version by Darren Hart <dvhart@linux.intel.com>
16 *
17 *****************************************************************************/
18
19#include <errno.h>
20#include <getopt.h>
21#include <pthread.h>
22#include <stdio.h>
23#include <stdlib.h>
24#include <string.h>
25#include <time.h>
26#include "futextest.h"
27#include "logging.h"
28
29#define TEST_NAME "futex-requeue-pi-mismatched-ops"
30
31futex_t f1 = FUTEX_INITIALIZER;
32futex_t f2 = FUTEX_INITIALIZER;
33int child_ret = 0;
34
35void usage(char *prog)
36{
37	printf("Usage: %s\n", prog);
38	printf("  -c	Use color\n");
39	printf("  -h	Display this help message\n");
40	printf("  -v L	Verbosity level: %d=QUIET %d=CRITICAL %d=INFO\n",
41	       VQUIET, VCRITICAL, VINFO);
42}
43
44void *blocking_child(void *arg)
45{
46	child_ret = futex_wait(&f1, f1, NULL, FUTEX_PRIVATE_FLAG);
47	if (child_ret < 0) {
48		child_ret = -errno;
49		error("futex_wait\n", errno);
50	}
51	return (void *)&child_ret;
52}
53
54int main(int argc, char *argv[])
55{
56	int ret = RET_PASS;
57	pthread_t child;
58	int c;
59
60	while ((c = getopt(argc, argv, "chv:")) != -1) {
61		switch (c) {
62		case 'c':
63			log_color(1);
64			break;
65		case 'h':
66			usage(basename(argv[0]));
67			exit(0);
68		case 'v':
69			log_verbosity(atoi(optarg));
70			break;
71		default:
72			usage(basename(argv[0]));
73			exit(1);
74		}
75	}
76
77	ksft_print_header();
78	ksft_set_plan(1);
79	ksft_print_msg("%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(TEST_NAME, ret);
134	return ret;
135}
136