xref: /linux/tools/testing/selftests/futex/functional/futex_requeue_pi.c (revision 59e6295fac26b8e85c1ea859cdd89fa1e47519d7)
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 excercises the futex syscall op codes needed for requeuing
8  *      priority inheritance aware POSIX condition variables and mutexes.
9  *
10  * AUTHORS
11  *      Sripathi Kodi <sripathik@in.ibm.com>
12  *      Darren Hart <dvhart@linux.intel.com>
13  *
14  * HISTORY
15  *      2008-Jan-13: Initial version by Sripathi Kodi <sripathik@in.ibm.com>
16  *      2009-Nov-6: futex test adaptation by Darren Hart <dvhart@linux.intel.com>
17  *
18  *****************************************************************************/
19 
20 #define _GNU_SOURCE
21 
22 #include <errno.h>
23 #include <limits.h>
24 #include <pthread.h>
25 #include <stdio.h>
26 #include <stdlib.h>
27 #include <signal.h>
28 #include <string.h>
29 
30 #include "atomic.h"
31 #include "futextest.h"
32 #include "kselftest_harness.h"
33 
34 #define MAX_WAKE_ITERS 1000
35 #define THREAD_MAX 10
36 #define SIGNAL_PERIOD_US 100
37 
38 atomic_t waiters_blocked = ATOMIC_INITIALIZER;
39 atomic_t waiters_woken = ATOMIC_INITIALIZER;
40 
41 futex_t f1 = FUTEX_INITIALIZER;
42 futex_t f2 = FUTEX_INITIALIZER;
43 futex_t wake_complete = FUTEX_INITIALIZER;
44 
45 struct thread_arg {
46 	struct __test_metadata	*_metadata;
47 	long			id;
48 	struct timespec		*timeout;
49 	int			lock;
50 	int			ret;
51 };
52 #define THREAD_ARG_INITIALIZER { NULL, 0, NULL, 0, 0 }
53 
54 FIXTURE(args)
55 {
56 };
57 
58 FIXTURE_SETUP(args)
59 {
60 };
61 
62 FIXTURE_TEARDOWN(args)
63 {
64 };
65 
66 FIXTURE_VARIANT(args)
67 {
68 	long timeout_ns;
69 	bool broadcast;
70 	bool owner;
71 	bool locked;
72 };
73 
74 /*
75  * For a given timeout value, this macro creates a test input with all the
76  * possible combinations of valid arguments
77  */
78 #define FIXTURE_VARIANT_ADD_TIMEOUT(timeout)		\
79 							\
80 FIXTURE_VARIANT_ADD(args, t_##timeout)			\
81 {							\
82 	.timeout_ns = timeout,				\
83 };							\
84 							\
85 FIXTURE_VARIANT_ADD(args, t_##timeout##_broadcast)	\
86 {							\
87 	.timeout_ns = timeout,				\
88 	.broadcast = true,				\
89 };							\
90 							\
91 FIXTURE_VARIANT_ADD(args, t_##timeout##_broadcast_locked) \
92 {							\
93 	.timeout_ns = timeout,				\
94 	.broadcast = true,				\
95 	.locked = true,					\
96 };							\
97 							\
98 FIXTURE_VARIANT_ADD(args, t_##timeout##_broadcast_owner) \
99 {							\
100 	.timeout_ns = timeout,				\
101 	.broadcast = true,				\
102 	.owner = true,					\
103 };							\
104 							\
105 FIXTURE_VARIANT_ADD(args, t_##timeout##_locked)		\
106 {							\
107 	.timeout_ns = timeout,				\
108 	.locked = true,					\
109 };							\
110 							\
111 FIXTURE_VARIANT_ADD(args, t_##timeout##_owner)		\
112 {							\
113 	.timeout_ns = timeout,				\
114 	.owner = true,					\
115 };							\
116 
117 FIXTURE_VARIANT_ADD_TIMEOUT(0);
118 FIXTURE_VARIANT_ADD_TIMEOUT(5000);
119 FIXTURE_VARIANT_ADD_TIMEOUT(500000);
120 FIXTURE_VARIANT_ADD_TIMEOUT(2000000000);
121 
122 int create_rt_thread(struct __test_metadata *_metadata, pthread_t *pth, void*(*func)(void *), void *arg,
123 		     int policy, int prio)
124 {
125 	int ret;
126 	struct sched_param schedp;
127 	pthread_attr_t attr;
128 
129 	pthread_attr_init(&attr);
130 	memset(&schedp, 0, sizeof(schedp));
131 
132 	ret = pthread_attr_setinheritsched(&attr, PTHREAD_EXPLICIT_SCHED);
133 	ASSERT_EQ(ret, 0)
134 		TH_LOG("pthread_attr_setinheritsched failed");
135 
136 	ret = pthread_attr_setschedpolicy(&attr, policy);
137 	ASSERT_EQ(ret, 0)
138 		TH_LOG("pthread_attr_setschedpolicy failed");
139 
140 	schedp.sched_priority = prio;
141 	ret = pthread_attr_setschedparam(&attr, &schedp);
142 	ASSERT_EQ(ret, 0)
143 		TH_LOG("pthread_attr_setschedparam failed");
144 
145 	ret = pthread_create(pth, &attr, func, arg);
146 	ASSERT_EQ(ret, 0)
147 		TH_LOG("pthread_create failed");
148 
149 	return 0;
150 }
151 
152 
153 void *waiterfn(void *arg)
154 {
155 	struct thread_arg *args = (struct thread_arg *)arg;
156 	struct __test_metadata *_metadata = args->_metadata;
157 	futex_t old_val;
158 
159 	TH_LOG("Waiter %ld: running", args->id);
160 	/* Each thread sleeps for a different amount of time
161 	 * This is to avoid races, because we don't lock the
162 	 * external mutex here
163 	 */
164 	usleep(1000 * (long)args->id);
165 
166 	old_val = f1;
167 	atomic_inc(&waiters_blocked);
168 	TH_LOG("Calling futex_wait_requeue_pi: %p (%u) -> %p", &f1, f1, &f2);
169 	args->ret = futex_wait_requeue_pi(&f1, old_val, &f2, args->timeout,
170 					  FUTEX_PRIVATE_FLAG);
171 
172 	TH_LOG("waiter %ld woke with %d %s", args->id, args->ret,
173 	       args->ret < 0 ? strerror(errno) : "");
174 	atomic_inc(&waiters_woken);
175 	if (args->ret < 0) {
176 		if (args->timeout && errno == ETIMEDOUT) {
177 			args->ret = 0;
178 		} else {
179 			ASSERT_EQ(args->ret, 0)
180 				TH_LOG("futex_wait_requeue_pi failed: %s", strerror(errno));
181 		}
182 		futex_lock_pi(&f2, NULL, 0, FUTEX_PRIVATE_FLAG);
183 	}
184 	futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
185 
186 	TH_LOG("Waiter %ld: exiting with %d", args->id, args->ret);
187 	pthread_exit((void *)&args->ret);
188 }
189 
190 void *broadcast_wakerfn(void *arg)
191 {
192 	struct thread_arg *args = (struct thread_arg *)arg;
193 	struct __test_metadata *_metadata = args->_metadata;
194 	int nr_requeue = INT_MAX;
195 	int task_count = 0;
196 	futex_t old_val;
197 	int nr_wake = 1;
198 	int i = 0;
199 
200 	TH_LOG("Waker: waiting for waiters to block");
201 	while (waiters_blocked.val < THREAD_MAX)
202 		usleep(1000);
203 	usleep(1000);
204 
205 	TH_LOG("Waker: Calling broadcast");
206 	if (args->lock) {
207 		TH_LOG("Calling FUTEX_LOCK_PI on mutex=%x @ %p", f2, &f2);
208 		futex_lock_pi(&f2, NULL, 0, FUTEX_PRIVATE_FLAG);
209 	}
210  continue_requeue:
211 	old_val = f1;
212 	args->ret = futex_cmp_requeue_pi(&f1, old_val, &f2, nr_wake, nr_requeue,
213 					 FUTEX_PRIVATE_FLAG);
214 	if (args->ret < 0) {
215 		ASSERT_GE(args->ret, 0)
216 			TH_LOG("FUTEX_CMP_REQUEUE_PI failed: %s", strerror(errno));
217 	} else if (++i < MAX_WAKE_ITERS) {
218 		task_count += args->ret;
219 		if (task_count < THREAD_MAX - waiters_woken.val)
220 			goto continue_requeue;
221 	} else {
222 		ASSERT_TRUE(0) {
223 			TH_LOG("max broadcast iterations (%d) reached with %d/%d tasks woken or requeued",
224 			       MAX_WAKE_ITERS, task_count, THREAD_MAX);
225 		}
226 	}
227 
228 	futex_wake(&wake_complete, 1, FUTEX_PRIVATE_FLAG);
229 
230 	if (args->lock)
231 		futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
232 
233 	if (args->ret > 0)
234 		args->ret = task_count;
235 
236 	TH_LOG("Waker: exiting with %d", args->ret);
237 	pthread_exit((void *)&args->ret);
238 }
239 
240 void *signal_wakerfn(void *arg)
241 {
242 	struct thread_arg *args = (struct thread_arg *)arg;
243 	struct __test_metadata *_metadata = args->_metadata;
244 	unsigned int old_val;
245 	int nr_requeue = 0;
246 	int task_count = 0;
247 	int nr_wake = 1;
248 	int i = 0;
249 
250 	TH_LOG("Waker: waiting for waiters to block");
251 	while (waiters_blocked.val < THREAD_MAX)
252 		usleep(1000);
253 	usleep(1000);
254 
255 	while (task_count < THREAD_MAX && waiters_woken.val < THREAD_MAX) {
256 		TH_LOG("task_count: %d, waiters_woken: %d",
257 		     task_count, waiters_woken.val);
258 		if (args->lock) {
259 			TH_LOG("Calling FUTEX_LOCK_PI on mutex=%x @ %p", f2, &f2);
260 			futex_lock_pi(&f2, NULL, 0, FUTEX_PRIVATE_FLAG);
261 		}
262 		TH_LOG("Waker: Calling signal");
263 		/* cond_signal */
264 		old_val = f1;
265 		args->ret = futex_cmp_requeue_pi(&f1, old_val, &f2,
266 						 nr_wake, nr_requeue,
267 						 FUTEX_PRIVATE_FLAG);
268 		if (args->ret < 0)
269 			args->ret = -errno;
270 		TH_LOG("futex: %x", f2);
271 		if (args->lock) {
272 			TH_LOG("Calling FUTEX_UNLOCK_PI on mutex=%x @ %p",
273 			    f2, &f2);
274 			futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
275 		}
276 		TH_LOG("futex: %x", f2);
277 		if (args->ret < 0) {
278 			ASSERT_GE(args->ret, 0)
279 				TH_LOG("FUTEX_CMP_REQUEUE_PI failed: %s", strerror(-args->ret));
280 		}
281 
282 		task_count += args->ret;
283 		usleep(SIGNAL_PERIOD_US);
284 		i++;
285 		/* we have to loop at least THREAD_MAX times */
286 		if (i > MAX_WAKE_ITERS + THREAD_MAX) {
287 			ASSERT_TRUE(0) {
288 				TH_LOG("max signaling iterations (%d) reached, giving up on pending waiters.",
289 				       MAX_WAKE_ITERS + THREAD_MAX);
290 			}
291 		}
292 	}
293 
294 	futex_wake(&wake_complete, 1, FUTEX_PRIVATE_FLAG);
295 
296 	if (args->ret >= 0)
297 		args->ret = task_count;
298 
299 	TH_LOG("Waker: exiting with %d", args->ret);
300 	TH_LOG("Waker: waiters_woken: %d", waiters_woken.val);
301 	pthread_exit((void *)&args->ret);
302 }
303 
304 void *third_party_blocker(void *arg)
305 {
306 	struct thread_arg *args = (struct thread_arg *)arg;
307 	struct __test_metadata *_metadata = args->_metadata;
308 	int ret2 = 0;
309 
310 	args->ret = futex_lock_pi(&f2, NULL, 0, FUTEX_PRIVATE_FLAG);
311 	if (args->ret)
312 		goto out;
313 	args->ret = futex_wait(&wake_complete, wake_complete, NULL,
314 			       FUTEX_PRIVATE_FLAG);
315 	ret2 = futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
316 
317  out:
318 	if (args->ret || ret2) {
319 		ASSERT_TRUE(0)
320 			TH_LOG("%s() futex error", __func__);
321 	}
322 
323 	pthread_exit((void *)&args->ret);
324 }
325 
326 TEST_F(args, futex_requeue_pi)
327 {
328 	struct thread_arg blocker_arg = THREAD_ARG_INITIALIZER;
329 	struct thread_arg waker_arg = THREAD_ARG_INITIALIZER;
330 	pthread_t waiter[THREAD_MAX], waker, blocker;
331 	void *(*wakerfn)(void *) = signal_wakerfn;
332 	bool third_party_owner = variant->owner;
333 	long timeout_ns = variant->timeout_ns;
334 	bool broadcast = variant->broadcast;
335 	struct thread_arg args[THREAD_MAX];
336 	struct timespec ts, *tsp = NULL;
337 	bool lock = variant->locked;
338 	int *waiter_ret, i, ret = 0;
339 
340 	TH_LOG("Arguments: broadcast=%d locked=%d owner=%d timeout=%ldns",
341 		broadcast, lock, third_party_owner, timeout_ns);
342 
343 	if (timeout_ns) {
344 		time_t secs;
345 
346 		TH_LOG("timeout_ns = %ld", timeout_ns);
347 		ret = clock_gettime(CLOCK_MONOTONIC, &ts);
348 		secs = (ts.tv_nsec + timeout_ns) / 1000000000;
349 		ts.tv_nsec = ((int64_t)ts.tv_nsec + timeout_ns) % 1000000000;
350 		ts.tv_sec += secs;
351 		TH_LOG("ts.tv_sec  = %ld", ts.tv_sec);
352 		TH_LOG("ts.tv_nsec = %ld", ts.tv_nsec);
353 		tsp = &ts;
354 	}
355 
356 	if (broadcast)
357 		wakerfn = broadcast_wakerfn;
358 
359 	if (third_party_owner) {
360 		blocker_arg._metadata = _metadata;
361 		create_rt_thread(_metadata, &blocker, third_party_blocker,
362 				 (void *)&blocker_arg, SCHED_FIFO, 1);
363 	}
364 
365 	atomic_set(&waiters_woken, 0);
366 	for (i = 0; i < THREAD_MAX; i++) {
367 		args[i]._metadata = _metadata;
368 		args[i].id = i;
369 		args[i].timeout = tsp;
370 		TH_LOG("Starting thread %d", i);
371 		create_rt_thread(_metadata, &waiter[i], waiterfn, (void *)&args[i],
372 				 SCHED_FIFO, 1);
373 	}
374 	waker_arg._metadata = _metadata;
375 	waker_arg.lock = lock;
376 	create_rt_thread(_metadata, &waker, wakerfn, (void *)&waker_arg, SCHED_FIFO, 1);
377 
378 	/* Wait for threads to finish */
379 	/* Store the first error or failure encountered in waiter_ret */
380 	waiter_ret = &args[0].ret;
381 	for (i = 0; i < THREAD_MAX; i++)
382 		pthread_join(waiter[i], *waiter_ret ? NULL : (void **)&waiter_ret);
383 
384 	if (third_party_owner)
385 		pthread_join(blocker, NULL);
386 	pthread_join(waker, NULL);
387 
388 	if (!ret) {
389 		if (*waiter_ret)
390 			ret = *waiter_ret;
391 		else if (waker_arg.ret < 0)
392 			ret = waker_arg.ret;
393 		else if (blocker_arg.ret)
394 			ret = blocker_arg.ret;
395 	}
396 
397 	EXPECT_EQ(ret, 0)
398 		TH_LOG("Test failed with error code: %d", ret);
399 }
400 
401 TEST_HARNESS_MAIN
402