1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /****************************************************************************** |
3 | * |
4 | * Copyright © International Business Machines Corp., 2006-2008 |
5 | * |
6 | * DESCRIPTION |
7 | * This test exercises the futex_wait_requeue_pi() signal handling both |
8 | * before and after the requeue. The first should be restarted by the |
9 | * kernel. The latter should return EWOULDBLOCK to the waiter. |
10 | * |
11 | * AUTHORS |
12 | * Darren Hart <dvhart@linux.intel.com> |
13 | * |
14 | * HISTORY |
15 | * 2008-May-5: Initial version by Darren Hart <dvhart@linux.intel.com> |
16 | * |
17 | *****************************************************************************/ |
18 | |
19 | #include <errno.h> |
20 | #include <getopt.h> |
21 | #include <limits.h> |
22 | #include <pthread.h> |
23 | #include <signal.h> |
24 | #include <stdio.h> |
25 | #include <stdlib.h> |
26 | #include <string.h> |
27 | #include "atomic.h" |
28 | #include "futextest.h" |
29 | #include "logging.h" |
30 | |
31 | #define TEST_NAME "futex-requeue-pi-signal-restart" |
32 | #define DELAY_US 100 |
33 | |
34 | futex_t f1 = FUTEX_INITIALIZER; |
35 | futex_t f2 = FUTEX_INITIALIZER; |
36 | atomic_t requeued = ATOMIC_INITIALIZER; |
37 | |
38 | int waiter_ret = 0; |
39 | |
40 | void usage(char *prog) |
41 | { |
42 | printf("Usage: %s\n" , prog); |
43 | printf(" -c Use color\n" ); |
44 | printf(" -h Display this help message\n" ); |
45 | printf(" -v L Verbosity level: %d=QUIET %d=CRITICAL %d=INFO\n" , |
46 | VQUIET, VCRITICAL, VINFO); |
47 | } |
48 | |
49 | int create_rt_thread(pthread_t *pth, void*(*func)(void *), void *arg, |
50 | int policy, int prio) |
51 | { |
52 | struct sched_param schedp; |
53 | pthread_attr_t attr; |
54 | int ret; |
55 | |
56 | pthread_attr_init(&attr); |
57 | memset(&schedp, 0, sizeof(schedp)); |
58 | |
59 | ret = pthread_attr_setinheritsched(&attr, PTHREAD_EXPLICIT_SCHED); |
60 | if (ret) { |
61 | error("pthread_attr_setinheritsched\n" , ret); |
62 | return -1; |
63 | } |
64 | |
65 | ret = pthread_attr_setschedpolicy(&attr, policy); |
66 | if (ret) { |
67 | error("pthread_attr_setschedpolicy\n" , ret); |
68 | return -1; |
69 | } |
70 | |
71 | schedp.sched_priority = prio; |
72 | ret = pthread_attr_setschedparam(&attr, &schedp); |
73 | if (ret) { |
74 | error("pthread_attr_setschedparam\n" , ret); |
75 | return -1; |
76 | } |
77 | |
78 | ret = pthread_create(pth, &attr, func, arg); |
79 | if (ret) { |
80 | error("pthread_create\n" , ret); |
81 | return -1; |
82 | } |
83 | return 0; |
84 | } |
85 | |
86 | void handle_signal(int signo) |
87 | { |
88 | info("signal received %s requeue\n" , |
89 | requeued.val ? "after" : "prior to" ); |
90 | } |
91 | |
92 | void *waiterfn(void *arg) |
93 | { |
94 | unsigned int old_val; |
95 | int res; |
96 | |
97 | waiter_ret = RET_PASS; |
98 | |
99 | info("Waiter running\n" ); |
100 | info("Calling FUTEX_LOCK_PI on f2=%x @ %p\n" , f2, &f2); |
101 | old_val = f1; |
102 | res = futex_wait_requeue_pi(&f1, old_val, &(f2), NULL, |
103 | FUTEX_PRIVATE_FLAG); |
104 | if (!requeued.val || errno != EWOULDBLOCK) { |
105 | fail("unexpected return from futex_wait_requeue_pi: %d (%s)\n" , |
106 | res, strerror(errno)); |
107 | info("w2:futex: %x\n" , f2); |
108 | if (!res) |
109 | futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG); |
110 | waiter_ret = RET_FAIL; |
111 | } |
112 | |
113 | info("Waiter exiting with %d\n" , waiter_ret); |
114 | pthread_exit(NULL); |
115 | } |
116 | |
117 | |
118 | int main(int argc, char *argv[]) |
119 | { |
120 | unsigned int old_val; |
121 | struct sigaction sa; |
122 | pthread_t waiter; |
123 | int c, res, ret = RET_PASS; |
124 | |
125 | while ((c = getopt(argc, argv, "chv:" )) != -1) { |
126 | switch (c) { |
127 | case 'c': |
128 | log_color(1); |
129 | break; |
130 | case 'h': |
131 | usage(prog: basename(argv[0])); |
132 | exit(0); |
133 | case 'v': |
134 | log_verbosity(atoi(optarg)); |
135 | break; |
136 | default: |
137 | usage(prog: basename(argv[0])); |
138 | exit(1); |
139 | } |
140 | } |
141 | |
142 | ksft_print_header(); |
143 | ksft_set_plan(1); |
144 | ksft_print_msg("%s: Test signal handling during requeue_pi\n" , |
145 | basename(argv[0])); |
146 | ksft_print_msg("\tArguments: <none>\n" ); |
147 | |
148 | sa.sa_handler = handle_signal; |
149 | sigemptyset(&sa.sa_mask); |
150 | sa.sa_flags = 0; |
151 | if (sigaction(SIGUSR1, &sa, NULL)) { |
152 | error("sigaction\n" , errno); |
153 | exit(1); |
154 | } |
155 | |
156 | info("m1:f2: %x\n" , f2); |
157 | info("Creating waiter\n" ); |
158 | res = create_rt_thread(&waiter, waiterfn, NULL, SCHED_FIFO, 1); |
159 | if (res) { |
160 | error("Creating waiting thread failed" , res); |
161 | ret = RET_ERROR; |
162 | goto out; |
163 | } |
164 | |
165 | info("Calling FUTEX_LOCK_PI on f2=%x @ %p\n" , f2, &f2); |
166 | info("m2:f2: %x\n" , f2); |
167 | futex_lock_pi(&f2, 0, 0, FUTEX_PRIVATE_FLAG); |
168 | info("m3:f2: %x\n" , f2); |
169 | |
170 | while (1) { |
171 | /* |
172 | * signal the waiter before requeue, waiter should automatically |
173 | * restart futex_wait_requeue_pi() in the kernel. Wait for the |
174 | * waiter to block on f1 again. |
175 | */ |
176 | info("Issuing SIGUSR1 to waiter\n" ); |
177 | pthread_kill(waiter, SIGUSR1); |
178 | usleep(DELAY_US); |
179 | |
180 | info("Requeueing waiter via FUTEX_CMP_REQUEUE_PI\n" ); |
181 | old_val = f1; |
182 | res = futex_cmp_requeue_pi(&f1, old_val, &(f2), 1, 0, |
183 | FUTEX_PRIVATE_FLAG); |
184 | /* |
185 | * If res is non-zero, we either requeued the waiter or hit an |
186 | * error, break out and handle it. If it is zero, then the |
187 | * signal may have hit before the waiter was blocked on f1. |
188 | * Try again. |
189 | */ |
190 | if (res > 0) { |
191 | atomic_set(&requeued, 1); |
192 | break; |
193 | } else if (res < 0) { |
194 | error("FUTEX_CMP_REQUEUE_PI failed\n" , errno); |
195 | ret = RET_ERROR; |
196 | break; |
197 | } |
198 | } |
199 | info("m4:f2: %x\n" , f2); |
200 | |
201 | /* |
202 | * Signal the waiter after requeue, waiter should return from |
203 | * futex_wait_requeue_pi() with EWOULDBLOCK. Join the thread here so the |
204 | * futex_unlock_pi() can't happen before the signal wakeup is detected |
205 | * in the kernel. |
206 | */ |
207 | info("Issuing SIGUSR1 to waiter\n" ); |
208 | pthread_kill(waiter, SIGUSR1); |
209 | info("Waiting for waiter to return\n" ); |
210 | pthread_join(waiter, NULL); |
211 | |
212 | info("Calling FUTEX_UNLOCK_PI on mutex=%x @ %p\n" , f2, &f2); |
213 | futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG); |
214 | info("m5:f2: %x\n" , f2); |
215 | |
216 | out: |
217 | if (ret == RET_PASS && waiter_ret) |
218 | ret = waiter_ret; |
219 | |
220 | print_result(TEST_NAME, ret); |
221 | return ret; |
222 | } |
223 | |