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 
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 
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 
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