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
31 futex_t f1 = FUTEX_INITIALIZER;
32 futex_t f2 = FUTEX_INITIALIZER;
33 int child_ret = 0;
34
usage(char * prog)35 void 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
blocking_child(void * arg)44 void *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
main(int argc,char * argv[])54 int 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
