1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
3 
4 #define _GNU_SOURCE
5 #include <linux/compiler.h>
6 #include <linux/ring_buffer.h>
7 #include <pthread.h>
8 #include <stdio.h>
9 #include <stdlib.h>
10 #include <sys/mman.h>
11 #include <sys/syscall.h>
12 #include <sys/sysinfo.h>
13 #include <test_progs.h>
14 #include <uapi/linux/bpf.h>
15 #include <unistd.h>
16 
17 #include "user_ringbuf_fail.skel.h"
18 #include "user_ringbuf_success.skel.h"
19 
20 #include "../progs/test_user_ringbuf.h"
21 
22 static const long c_sample_size = sizeof(struct sample) + BPF_RINGBUF_HDR_SZ;
23 static const long c_ringbuf_size = 1 << 12; /* 1 small page */
24 static const long c_max_entries = c_ringbuf_size / c_sample_size;
25 
26 static void drain_current_samples(void)
27 {
28 	syscall(__NR_getpgid);
29 }
30 
31 static int write_samples(struct user_ring_buffer *ringbuf, uint32_t num_samples)
32 {
33 	int i, err = 0;
34 
35 	/* Write some number of samples to the ring buffer. */
36 	for (i = 0; i < num_samples; i++) {
37 		struct sample *entry;
38 		int read;
39 
40 		entry = user_ring_buffer__reserve(ringbuf, sizeof(*entry));
41 		if (!entry) {
42 			err = -errno;
43 			goto done;
44 		}
45 
46 		entry->pid = getpid();
47 		entry->seq = i;
48 		entry->value = i * i;
49 
50 		read = snprintf(entry->comm, sizeof(entry->comm), "%u", i);
51 		if (read <= 0) {
52 			/* Assert on the error path to avoid spamming logs with
53 			 * mostly success messages.
54 			 */
55 			ASSERT_GT(read, 0, "snprintf_comm");
56 			err = read;
57 			user_ring_buffer__discard(ringbuf, entry);
58 			goto done;
59 		}
60 
61 		user_ring_buffer__submit(ringbuf, entry);
62 	}
63 
64 done:
65 	drain_current_samples();
66 
67 	return err;
68 }
69 
70 static struct user_ringbuf_success *open_load_ringbuf_skel(void)
71 {
72 	struct user_ringbuf_success *skel;
73 	int err;
74 
75 	skel = user_ringbuf_success__open();
76 	if (!ASSERT_OK_PTR(skel, "skel_open"))
77 		return NULL;
78 
79 	err = bpf_map__set_max_entries(skel->maps.user_ringbuf, c_ringbuf_size);
80 	if (!ASSERT_OK(err, "set_max_entries"))
81 		goto cleanup;
82 
83 	err = bpf_map__set_max_entries(skel->maps.kernel_ringbuf, c_ringbuf_size);
84 	if (!ASSERT_OK(err, "set_max_entries"))
85 		goto cleanup;
86 
87 	err = user_ringbuf_success__load(skel);
88 	if (!ASSERT_OK(err, "skel_load"))
89 		goto cleanup;
90 
91 	return skel;
92 
93 cleanup:
94 	user_ringbuf_success__destroy(skel);
95 	return NULL;
96 }
97 
98 static void test_user_ringbuf_mappings(void)
99 {
100 	int err, rb_fd;
101 	int page_size = getpagesize();
102 	void *mmap_ptr;
103 	struct user_ringbuf_success *skel;
104 
105 	skel = open_load_ringbuf_skel();
106 	if (!skel)
107 		return;
108 
109 	rb_fd = bpf_map__fd(skel->maps.user_ringbuf);
110 	/* cons_pos can be mapped R/O, can't add +X with mprotect. */
111 	mmap_ptr = mmap(NULL, page_size, PROT_READ, MAP_SHARED, rb_fd, 0);
112 	ASSERT_OK_PTR(mmap_ptr, "ro_cons_pos");
113 	ASSERT_ERR(mprotect(mmap_ptr, page_size, PROT_WRITE), "write_cons_pos_protect");
114 	ASSERT_ERR(mprotect(mmap_ptr, page_size, PROT_EXEC), "exec_cons_pos_protect");
115 	ASSERT_ERR_PTR(mremap(mmap_ptr, 0, 4 * page_size, MREMAP_MAYMOVE), "wr_prod_pos");
116 	err = -errno;
117 	ASSERT_ERR(err, "wr_prod_pos_err");
118 	ASSERT_OK(munmap(mmap_ptr, page_size), "unmap_ro_cons");
119 
120 	/* prod_pos can be mapped RW, can't add +X with mprotect. */
121 	mmap_ptr = mmap(NULL, page_size, PROT_READ | PROT_WRITE, MAP_SHARED,
122 			rb_fd, page_size);
123 	ASSERT_OK_PTR(mmap_ptr, "rw_prod_pos");
124 	ASSERT_ERR(mprotect(mmap_ptr, page_size, PROT_EXEC), "exec_prod_pos_protect");
125 	err = -errno;
126 	ASSERT_ERR(err, "wr_prod_pos_err");
127 	ASSERT_OK(munmap(mmap_ptr, page_size), "unmap_rw_prod");
128 
129 	/* data pages can be mapped RW, can't add +X with mprotect. */
130 	mmap_ptr = mmap(NULL, page_size, PROT_WRITE, MAP_SHARED, rb_fd,
131 			2 * page_size);
132 	ASSERT_OK_PTR(mmap_ptr, "rw_data");
133 	ASSERT_ERR(mprotect(mmap_ptr, page_size, PROT_EXEC), "exec_data_protect");
134 	err = -errno;
135 	ASSERT_ERR(err, "exec_data_err");
136 	ASSERT_OK(munmap(mmap_ptr, page_size), "unmap_rw_data");
137 
138 	user_ringbuf_success__destroy(skel);
139 }
140 
141 static int load_skel_create_ringbufs(struct user_ringbuf_success **skel_out,
142 				     struct ring_buffer **kern_ringbuf_out,
143 				     ring_buffer_sample_fn callback,
144 				     struct user_ring_buffer **user_ringbuf_out)
145 {
146 	struct user_ringbuf_success *skel;
147 	struct ring_buffer *kern_ringbuf = NULL;
148 	struct user_ring_buffer *user_ringbuf = NULL;
149 	int err = -ENOMEM, rb_fd;
150 
151 	skel = open_load_ringbuf_skel();
152 	if (!skel)
153 		return err;
154 
155 	/* only trigger BPF program for current process */
156 	skel->bss->pid = getpid();
157 
158 	if (kern_ringbuf_out) {
159 		rb_fd = bpf_map__fd(skel->maps.kernel_ringbuf);
160 		kern_ringbuf = ring_buffer__new(rb_fd, callback, skel, NULL);
161 		if (!ASSERT_OK_PTR(kern_ringbuf, "kern_ringbuf_create"))
162 			goto cleanup;
163 
164 		*kern_ringbuf_out = kern_ringbuf;
165 	}
166 
167 	if (user_ringbuf_out) {
168 		rb_fd = bpf_map__fd(skel->maps.user_ringbuf);
169 		user_ringbuf = user_ring_buffer__new(rb_fd, NULL);
170 		if (!ASSERT_OK_PTR(user_ringbuf, "user_ringbuf_create"))
171 			goto cleanup;
172 
173 		*user_ringbuf_out = user_ringbuf;
174 		ASSERT_EQ(skel->bss->read, 0, "no_reads_after_load");
175 	}
176 
177 	err = user_ringbuf_success__attach(skel);
178 	if (!ASSERT_OK(err, "skel_attach"))
179 		goto cleanup;
180 
181 	*skel_out = skel;
182 	return 0;
183 
184 cleanup:
185 	if (kern_ringbuf_out)
186 		*kern_ringbuf_out = NULL;
187 	if (user_ringbuf_out)
188 		*user_ringbuf_out = NULL;
189 	ring_buffer__free(kern_ringbuf);
190 	user_ring_buffer__free(user_ringbuf);
191 	user_ringbuf_success__destroy(skel);
192 	return err;
193 }
194 
195 static int load_skel_create_user_ringbuf(struct user_ringbuf_success **skel_out,
196 					 struct user_ring_buffer **ringbuf_out)
197 {
198 	return load_skel_create_ringbufs(skel_out, NULL, NULL, ringbuf_out);
199 }
200 
201 static void manually_write_test_invalid_sample(struct user_ringbuf_success *skel,
202 					       __u32 size, __u64 producer_pos, int err)
203 {
204 	void *data_ptr;
205 	__u64 *producer_pos_ptr;
206 	int rb_fd, page_size = getpagesize();
207 
208 	rb_fd = bpf_map__fd(skel->maps.user_ringbuf);
209 
210 	ASSERT_EQ(skel->bss->read, 0, "num_samples_before_bad_sample");
211 
212 	/* Map the producer_pos as RW. */
213 	producer_pos_ptr = mmap(NULL, page_size, PROT_READ | PROT_WRITE,
214 				MAP_SHARED, rb_fd, page_size);
215 	ASSERT_OK_PTR(producer_pos_ptr, "producer_pos_ptr");
216 
217 	/* Map the data pages as RW. */
218 	data_ptr = mmap(NULL, page_size, PROT_WRITE, MAP_SHARED, rb_fd, 2 * page_size);
219 	ASSERT_OK_PTR(data_ptr, "rw_data");
220 
221 	memset(data_ptr, 0, BPF_RINGBUF_HDR_SZ);
222 	*(__u32 *)data_ptr = size;
223 
224 	/* Synchronizes with smp_load_acquire() in __bpf_user_ringbuf_peek() in the kernel. */
225 	smp_store_release(producer_pos_ptr, producer_pos + BPF_RINGBUF_HDR_SZ);
226 
227 	drain_current_samples();
228 	ASSERT_EQ(skel->bss->read, 0, "num_samples_after_bad_sample");
229 	ASSERT_EQ(skel->bss->err, err, "err_after_bad_sample");
230 
231 	ASSERT_OK(munmap(producer_pos_ptr, page_size), "unmap_producer_pos");
232 	ASSERT_OK(munmap(data_ptr, page_size), "unmap_data_ptr");
233 }
234 
235 static void test_user_ringbuf_post_misaligned(void)
236 {
237 	struct user_ringbuf_success *skel;
238 	struct user_ring_buffer *ringbuf;
239 	int err;
240 	__u32 size = (1 << 5) + 7;
241 
242 	err = load_skel_create_user_ringbuf(&skel, &ringbuf);
243 	if (!ASSERT_OK(err, "misaligned_skel"))
244 		return;
245 
246 	manually_write_test_invalid_sample(skel, size, size, -EINVAL);
247 	user_ring_buffer__free(ringbuf);
248 	user_ringbuf_success__destroy(skel);
249 }
250 
251 static void test_user_ringbuf_post_producer_wrong_offset(void)
252 {
253 	struct user_ringbuf_success *skel;
254 	struct user_ring_buffer *ringbuf;
255 	int err;
256 	__u32 size = (1 << 5);
257 
258 	err = load_skel_create_user_ringbuf(&skel, &ringbuf);
259 	if (!ASSERT_OK(err, "wrong_offset_skel"))
260 		return;
261 
262 	manually_write_test_invalid_sample(skel, size, size - 8, -EINVAL);
263 	user_ring_buffer__free(ringbuf);
264 	user_ringbuf_success__destroy(skel);
265 }
266 
267 static void test_user_ringbuf_post_larger_than_ringbuf_sz(void)
268 {
269 	struct user_ringbuf_success *skel;
270 	struct user_ring_buffer *ringbuf;
271 	int err;
272 	__u32 size = c_ringbuf_size;
273 
274 	err = load_skel_create_user_ringbuf(&skel, &ringbuf);
275 	if (!ASSERT_OK(err, "huge_sample_skel"))
276 		return;
277 
278 	manually_write_test_invalid_sample(skel, size, size, -E2BIG);
279 	user_ring_buffer__free(ringbuf);
280 	user_ringbuf_success__destroy(skel);
281 }
282 
283 static void test_user_ringbuf_basic(void)
284 {
285 	struct user_ringbuf_success *skel;
286 	struct user_ring_buffer *ringbuf;
287 	int err;
288 
289 	err = load_skel_create_user_ringbuf(&skel, &ringbuf);
290 	if (!ASSERT_OK(err, "ringbuf_basic_skel"))
291 		return;
292 
293 	ASSERT_EQ(skel->bss->read, 0, "num_samples_read_before");
294 
295 	err = write_samples(ringbuf, 2);
296 	if (!ASSERT_OK(err, "write_samples"))
297 		goto cleanup;
298 
299 	ASSERT_EQ(skel->bss->read, 2, "num_samples_read_after");
300 
301 cleanup:
302 	user_ring_buffer__free(ringbuf);
303 	user_ringbuf_success__destroy(skel);
304 }
305 
306 static void test_user_ringbuf_sample_full_ring_buffer(void)
307 {
308 	struct user_ringbuf_success *skel;
309 	struct user_ring_buffer *ringbuf;
310 	int err;
311 	void *sample;
312 
313 	err = load_skel_create_user_ringbuf(&skel, &ringbuf);
314 	if (!ASSERT_OK(err, "ringbuf_full_sample_skel"))
315 		return;
316 
317 	sample = user_ring_buffer__reserve(ringbuf, c_ringbuf_size - BPF_RINGBUF_HDR_SZ);
318 	if (!ASSERT_OK_PTR(sample, "full_sample"))
319 		goto cleanup;
320 
321 	user_ring_buffer__submit(ringbuf, sample);
322 	ASSERT_EQ(skel->bss->read, 0, "num_samples_read_before");
323 	drain_current_samples();
324 	ASSERT_EQ(skel->bss->read, 1, "num_samples_read_after");
325 
326 cleanup:
327 	user_ring_buffer__free(ringbuf);
328 	user_ringbuf_success__destroy(skel);
329 }
330 
331 static void test_user_ringbuf_post_alignment_autoadjust(void)
332 {
333 	struct user_ringbuf_success *skel;
334 	struct user_ring_buffer *ringbuf;
335 	struct sample *sample;
336 	int err;
337 
338 	err = load_skel_create_user_ringbuf(&skel, &ringbuf);
339 	if (!ASSERT_OK(err, "ringbuf_align_autoadjust_skel"))
340 		return;
341 
342 	/* libbpf should automatically round any sample up to an 8-byte alignment. */
343 	sample = user_ring_buffer__reserve(ringbuf, sizeof(*sample) + 1);
344 	ASSERT_OK_PTR(sample, "reserve_autoaligned");
345 	user_ring_buffer__submit(ringbuf, sample);
346 
347 	ASSERT_EQ(skel->bss->read, 0, "num_samples_read_before");
348 	drain_current_samples();
349 	ASSERT_EQ(skel->bss->read, 1, "num_samples_read_after");
350 
351 	user_ring_buffer__free(ringbuf);
352 	user_ringbuf_success__destroy(skel);
353 }
354 
355 static void test_user_ringbuf_overfill(void)
356 {
357 	struct user_ringbuf_success *skel;
358 	struct user_ring_buffer *ringbuf;
359 	int err;
360 
361 	err = load_skel_create_user_ringbuf(&skel, &ringbuf);
362 	if (err)
363 		return;
364 
365 	err = write_samples(ringbuf, c_max_entries * 5);
366 	ASSERT_ERR(err, "write_samples");
367 	ASSERT_EQ(skel->bss->read, c_max_entries, "max_entries");
368 
369 	user_ring_buffer__free(ringbuf);
370 	user_ringbuf_success__destroy(skel);
371 }
372 
373 static void test_user_ringbuf_discards_properly_ignored(void)
374 {
375 	struct user_ringbuf_success *skel;
376 	struct user_ring_buffer *ringbuf;
377 	int err, num_discarded = 0;
378 	__u64 *token;
379 
380 	err = load_skel_create_user_ringbuf(&skel, &ringbuf);
381 	if (err)
382 		return;
383 
384 	ASSERT_EQ(skel->bss->read, 0, "num_samples_read_before");
385 
386 	while (1) {
387 		/* Write samples until the buffer is full. */
388 		token = user_ring_buffer__reserve(ringbuf, sizeof(*token));
389 		if (!token)
390 			break;
391 
392 		user_ring_buffer__discard(ringbuf, token);
393 		num_discarded++;
394 	}
395 
396 	if (!ASSERT_GE(num_discarded, 0, "num_discarded"))
397 		goto cleanup;
398 
399 	/* Should not read any samples, as they are all discarded. */
400 	ASSERT_EQ(skel->bss->read, 0, "num_pre_kick");
401 	drain_current_samples();
402 	ASSERT_EQ(skel->bss->read, 0, "num_post_kick");
403 
404 	/* Now that the ring buffer has been drained, we should be able to
405 	 * reserve another token.
406 	 */
407 	token = user_ring_buffer__reserve(ringbuf, sizeof(*token));
408 
409 	if (!ASSERT_OK_PTR(token, "new_token"))
410 		goto cleanup;
411 
412 	user_ring_buffer__discard(ringbuf, token);
413 cleanup:
414 	user_ring_buffer__free(ringbuf);
415 	user_ringbuf_success__destroy(skel);
416 }
417 
418 static void test_user_ringbuf_loop(void)
419 {
420 	struct user_ringbuf_success *skel;
421 	struct user_ring_buffer *ringbuf;
422 	uint32_t total_samples = 8192;
423 	uint32_t remaining_samples = total_samples;
424 	int err;
425 
426 	BUILD_BUG_ON(total_samples <= c_max_entries);
427 	err = load_skel_create_user_ringbuf(&skel, &ringbuf);
428 	if (err)
429 		return;
430 
431 	do  {
432 		uint32_t curr_samples;
433 
434 		curr_samples = remaining_samples > c_max_entries
435 			? c_max_entries : remaining_samples;
436 		err = write_samples(ringbuf, curr_samples);
437 		if (err != 0) {
438 			/* Assert inside of if statement to avoid flooding logs
439 			 * on the success path.
440 			 */
441 			ASSERT_OK(err, "write_samples");
442 			goto cleanup;
443 		}
444 
445 		remaining_samples -= curr_samples;
446 		ASSERT_EQ(skel->bss->read, total_samples - remaining_samples,
447 			  "current_batched_entries");
448 	} while (remaining_samples > 0);
449 	ASSERT_EQ(skel->bss->read, total_samples, "total_batched_entries");
450 
451 cleanup:
452 	user_ring_buffer__free(ringbuf);
453 	user_ringbuf_success__destroy(skel);
454 }
455 
456 static int send_test_message(struct user_ring_buffer *ringbuf,
457 			     enum test_msg_op op, s64 operand_64,
458 			     s32 operand_32)
459 {
460 	struct test_msg *msg;
461 
462 	msg = user_ring_buffer__reserve(ringbuf, sizeof(*msg));
463 	if (!msg) {
464 		/* Assert on the error path to avoid spamming logs with mostly
465 		 * success messages.
466 		 */
467 		ASSERT_OK_PTR(msg, "reserve_msg");
468 		return -ENOMEM;
469 	}
470 
471 	msg->msg_op = op;
472 
473 	switch (op) {
474 	case TEST_MSG_OP_INC64:
475 	case TEST_MSG_OP_MUL64:
476 		msg->operand_64 = operand_64;
477 		break;
478 	case TEST_MSG_OP_INC32:
479 	case TEST_MSG_OP_MUL32:
480 		msg->operand_32 = operand_32;
481 		break;
482 	default:
483 		PRINT_FAIL("Invalid operand %d\n", op);
484 		user_ring_buffer__discard(ringbuf, msg);
485 		return -EINVAL;
486 	}
487 
488 	user_ring_buffer__submit(ringbuf, msg);
489 
490 	return 0;
491 }
492 
493 static void kick_kernel_read_messages(void)
494 {
495 	syscall(__NR_prctl);
496 }
497 
498 static int handle_kernel_msg(void *ctx, void *data, size_t len)
499 {
500 	struct user_ringbuf_success *skel = ctx;
501 	struct test_msg *msg = data;
502 
503 	switch (msg->msg_op) {
504 	case TEST_MSG_OP_INC64:
505 		skel->bss->user_mutated += msg->operand_64;
506 		return 0;
507 	case TEST_MSG_OP_INC32:
508 		skel->bss->user_mutated += msg->operand_32;
509 		return 0;
510 	case TEST_MSG_OP_MUL64:
511 		skel->bss->user_mutated *= msg->operand_64;
512 		return 0;
513 	case TEST_MSG_OP_MUL32:
514 		skel->bss->user_mutated *= msg->operand_32;
515 		return 0;
516 	default:
517 		fprintf(stderr, "Invalid operand %d\n", msg->msg_op);
518 		return -EINVAL;
519 	}
520 }
521 
522 static void drain_kernel_messages_buffer(struct ring_buffer *kern_ringbuf,
523 					 struct user_ringbuf_success *skel)
524 {
525 	int cnt;
526 
527 	cnt = ring_buffer__consume(kern_ringbuf);
528 	ASSERT_EQ(cnt, 8, "consume_kern_ringbuf");
529 	ASSERT_OK(skel->bss->err, "consume_kern_ringbuf_err");
530 }
531 
532 static void test_user_ringbuf_msg_protocol(void)
533 {
534 	struct user_ringbuf_success *skel;
535 	struct user_ring_buffer *user_ringbuf;
536 	struct ring_buffer *kern_ringbuf;
537 	int err, i;
538 	__u64 expected_kern = 0;
539 
540 	err = load_skel_create_ringbufs(&skel, &kern_ringbuf, handle_kernel_msg, &user_ringbuf);
541 	if (!ASSERT_OK(err, "create_ringbufs"))
542 		return;
543 
544 	for (i = 0; i < 64; i++) {
545 		enum test_msg_op op = i % TEST_MSG_OP_NUM_OPS;
546 		__u64 operand_64 = TEST_OP_64;
547 		__u32 operand_32 = TEST_OP_32;
548 
549 		err = send_test_message(user_ringbuf, op, operand_64, operand_32);
550 		if (err) {
551 			/* Only assert on a failure to avoid spamming success logs. */
552 			ASSERT_OK(err, "send_test_message");
553 			goto cleanup;
554 		}
555 
556 		switch (op) {
557 		case TEST_MSG_OP_INC64:
558 			expected_kern += operand_64;
559 			break;
560 		case TEST_MSG_OP_INC32:
561 			expected_kern += operand_32;
562 			break;
563 		case TEST_MSG_OP_MUL64:
564 			expected_kern *= operand_64;
565 			break;
566 		case TEST_MSG_OP_MUL32:
567 			expected_kern *= operand_32;
568 			break;
569 		default:
570 			PRINT_FAIL("Unexpected op %d\n", op);
571 			goto cleanup;
572 		}
573 
574 		if (i % 8 == 0) {
575 			kick_kernel_read_messages();
576 			ASSERT_EQ(skel->bss->kern_mutated, expected_kern, "expected_kern");
577 			ASSERT_EQ(skel->bss->err, 0, "bpf_prog_err");
578 			drain_kernel_messages_buffer(kern_ringbuf, skel);
579 		}
580 	}
581 
582 cleanup:
583 	ring_buffer__free(kern_ringbuf);
584 	user_ring_buffer__free(user_ringbuf);
585 	user_ringbuf_success__destroy(skel);
586 }
587 
588 static void *kick_kernel_cb(void *arg)
589 {
590 	/* Kick the kernel, causing it to drain the ring buffer and then wake
591 	 * up the test thread waiting on epoll.
592 	 */
593 	syscall(__NR_prlimit64);
594 
595 	return NULL;
596 }
597 
598 static int spawn_kick_thread_for_poll(void)
599 {
600 	pthread_t thread;
601 
602 	return pthread_create(&thread, NULL, kick_kernel_cb, NULL);
603 }
604 
605 static void test_user_ringbuf_blocking_reserve(void)
606 {
607 	struct user_ringbuf_success *skel;
608 	struct user_ring_buffer *ringbuf;
609 	int err, num_written = 0;
610 	__u64 *token;
611 
612 	err = load_skel_create_user_ringbuf(&skel, &ringbuf);
613 	if (err)
614 		return;
615 
616 	ASSERT_EQ(skel->bss->read, 0, "num_samples_read_before");
617 
618 	while (1) {
619 		/* Write samples until the buffer is full. */
620 		token = user_ring_buffer__reserve(ringbuf, sizeof(*token));
621 		if (!token)
622 			break;
623 
624 		*token = 0xdeadbeef;
625 
626 		user_ring_buffer__submit(ringbuf, token);
627 		num_written++;
628 	}
629 
630 	if (!ASSERT_GE(num_written, 0, "num_written"))
631 		goto cleanup;
632 
633 	/* Should not have read any samples until the kernel is kicked. */
634 	ASSERT_EQ(skel->bss->read, 0, "num_pre_kick");
635 
636 	/* We correctly time out after 1 second, without a sample. */
637 	token = user_ring_buffer__reserve_blocking(ringbuf, sizeof(*token), 1000);
638 	if (!ASSERT_EQ(token, NULL, "pre_kick_timeout_token"))
639 		goto cleanup;
640 
641 	err = spawn_kick_thread_for_poll();
642 	if (!ASSERT_EQ(err, 0, "deferred_kick_thread\n"))
643 		goto cleanup;
644 
645 	/* After spawning another thread that asychronously kicks the kernel to
646 	 * drain the messages, we're able to block and successfully get a
647 	 * sample once we receive an event notification.
648 	 */
649 	token = user_ring_buffer__reserve_blocking(ringbuf, sizeof(*token), 10000);
650 
651 	if (!ASSERT_OK_PTR(token, "block_token"))
652 		goto cleanup;
653 
654 	ASSERT_GT(skel->bss->read, 0, "num_post_kill");
655 	ASSERT_LE(skel->bss->read, num_written, "num_post_kill");
656 	ASSERT_EQ(skel->bss->err, 0, "err_post_poll");
657 	user_ring_buffer__discard(ringbuf, token);
658 
659 cleanup:
660 	user_ring_buffer__free(ringbuf);
661 	user_ringbuf_success__destroy(skel);
662 }
663 
664 #define SUCCESS_TEST(_func) { _func, #_func }
665 
666 static struct {
667 	void (*test_callback)(void);
668 	const char *test_name;
669 } success_tests[] = {
670 	SUCCESS_TEST(test_user_ringbuf_mappings),
671 	SUCCESS_TEST(test_user_ringbuf_post_misaligned),
672 	SUCCESS_TEST(test_user_ringbuf_post_producer_wrong_offset),
673 	SUCCESS_TEST(test_user_ringbuf_post_larger_than_ringbuf_sz),
674 	SUCCESS_TEST(test_user_ringbuf_basic),
675 	SUCCESS_TEST(test_user_ringbuf_sample_full_ring_buffer),
676 	SUCCESS_TEST(test_user_ringbuf_post_alignment_autoadjust),
677 	SUCCESS_TEST(test_user_ringbuf_overfill),
678 	SUCCESS_TEST(test_user_ringbuf_discards_properly_ignored),
679 	SUCCESS_TEST(test_user_ringbuf_loop),
680 	SUCCESS_TEST(test_user_ringbuf_msg_protocol),
681 	SUCCESS_TEST(test_user_ringbuf_blocking_reserve),
682 };
683 
684 void test_user_ringbuf(void)
685 {
686 	int i;
687 
688 	for (i = 0; i < ARRAY_SIZE(success_tests); i++) {
689 		if (!test__start_subtest(success_tests[i].test_name))
690 			continue;
691 
692 		success_tests[i].test_callback();
693 	}
694 
695 	RUN_TESTS(user_ringbuf_fail);
696 }
697