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
35 futex_t f1 = FUTEX_INITIALIZER;
36 futex_t f2 = FUTEX_INITIALIZER;
37 int child_ret = 0;
38
usage(char * prog)39 void 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
blocking_child(void * arg)48 void *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
main(int argc,char * argv[])58 int 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