1 // SPDX-License-Identifier: GPL-2.0
2 #define _GNU_SOURCE
3 #include <linux/compiler.h>
4 #include <asm/barrier.h>
5 #include <test_progs.h>
6 #include <sys/mman.h>
7 #include <sys/epoll.h>
8 #include <time.h>
9 #include <sched.h>
10 #include <signal.h>
11 #include <pthread.h>
12 #include <sys/sysinfo.h>
13 #include <linux/perf_event.h>
14 #include <linux/ring_buffer.h>
15 #include "test_ringbuf.lskel.h"
16
17 #define EDONE 7777
18
19 static int duration = 0;
20
21 struct sample {
22 int pid;
23 int seq;
24 long value;
25 char comm[16];
26 };
27
28 static int sample_cnt;
29
atomic_inc(int * cnt)30 static void atomic_inc(int *cnt)
31 {
32 __atomic_add_fetch(cnt, 1, __ATOMIC_SEQ_CST);
33 }
34
atomic_xchg(int * cnt,int val)35 static int atomic_xchg(int *cnt, int val)
36 {
37 return __atomic_exchange_n(cnt, val, __ATOMIC_SEQ_CST);
38 }
39
process_sample(void * ctx,void * data,size_t len)40 static int process_sample(void *ctx, void *data, size_t len)
41 {
42 struct sample *s = data;
43
44 atomic_inc(&sample_cnt);
45
46 switch (s->seq) {
47 case 0:
48 CHECK(s->value != 333, "sample1_value", "exp %ld, got %ld\n",
49 333L, s->value);
50 return 0;
51 case 1:
52 CHECK(s->value != 777, "sample2_value", "exp %ld, got %ld\n",
53 777L, s->value);
54 return -EDONE;
55 default:
56 /* we don't care about the rest */
57 return 0;
58 }
59 }
60
61 static struct test_ringbuf *skel;
62 static struct ring_buffer *ringbuf;
63
trigger_samples()64 static void trigger_samples()
65 {
66 skel->bss->dropped = 0;
67 skel->bss->total = 0;
68 skel->bss->discarded = 0;
69
70 /* trigger exactly two samples */
71 skel->bss->value = 333;
72 syscall(__NR_getpgid);
73 skel->bss->value = 777;
74 syscall(__NR_getpgid);
75 }
76
poll_thread(void * input)77 static void *poll_thread(void *input)
78 {
79 long timeout = (long)input;
80
81 return (void *)(long)ring_buffer__poll(ringbuf, timeout);
82 }
83
test_ringbuf(void)84 void test_ringbuf(void)
85 {
86 const size_t rec_sz = BPF_RINGBUF_HDR_SZ + sizeof(struct sample);
87 pthread_t thread;
88 long bg_ret = -1;
89 int err, cnt, rb_fd;
90 int page_size = getpagesize();
91 void *mmap_ptr, *tmp_ptr;
92
93 skel = test_ringbuf__open();
94 if (CHECK(!skel, "skel_open", "skeleton open failed\n"))
95 return;
96
97 skel->maps.ringbuf.max_entries = page_size;
98
99 err = test_ringbuf__load(skel);
100 if (CHECK(err != 0, "skel_load", "skeleton load failed\n"))
101 goto cleanup;
102
103 rb_fd = skel->maps.ringbuf.map_fd;
104 /* good read/write cons_pos */
105 mmap_ptr = mmap(NULL, page_size, PROT_READ | PROT_WRITE, MAP_SHARED, rb_fd, 0);
106 ASSERT_OK_PTR(mmap_ptr, "rw_cons_pos");
107 tmp_ptr = mremap(mmap_ptr, page_size, 2 * page_size, MREMAP_MAYMOVE);
108 if (!ASSERT_ERR_PTR(tmp_ptr, "rw_extend"))
109 goto cleanup;
110 ASSERT_ERR(mprotect(mmap_ptr, page_size, PROT_EXEC), "exec_cons_pos_protect");
111 ASSERT_OK(munmap(mmap_ptr, page_size), "unmap_rw");
112
113 /* bad writeable prod_pos */
114 mmap_ptr = mmap(NULL, page_size, PROT_WRITE, MAP_SHARED, rb_fd, page_size);
115 err = -errno;
116 ASSERT_ERR_PTR(mmap_ptr, "wr_prod_pos");
117 ASSERT_EQ(err, -EPERM, "wr_prod_pos_err");
118
119 /* bad writeable data pages */
120 mmap_ptr = mmap(NULL, page_size, PROT_WRITE, MAP_SHARED, rb_fd, 2 * page_size);
121 err = -errno;
122 ASSERT_ERR_PTR(mmap_ptr, "wr_data_page_one");
123 ASSERT_EQ(err, -EPERM, "wr_data_page_one_err");
124 mmap_ptr = mmap(NULL, page_size, PROT_WRITE, MAP_SHARED, rb_fd, 3 * page_size);
125 ASSERT_ERR_PTR(mmap_ptr, "wr_data_page_two");
126 mmap_ptr = mmap(NULL, 2 * page_size, PROT_WRITE, MAP_SHARED, rb_fd, 2 * page_size);
127 ASSERT_ERR_PTR(mmap_ptr, "wr_data_page_all");
128
129 /* good read-only pages */
130 mmap_ptr = mmap(NULL, 4 * page_size, PROT_READ, MAP_SHARED, rb_fd, 0);
131 if (!ASSERT_OK_PTR(mmap_ptr, "ro_prod_pos"))
132 goto cleanup;
133
134 ASSERT_ERR(mprotect(mmap_ptr, 4 * page_size, PROT_WRITE), "write_protect");
135 ASSERT_ERR(mprotect(mmap_ptr, 4 * page_size, PROT_EXEC), "exec_protect");
136 ASSERT_ERR_PTR(mremap(mmap_ptr, 0, 4 * page_size, MREMAP_MAYMOVE), "ro_remap");
137 ASSERT_OK(munmap(mmap_ptr, 4 * page_size), "unmap_ro");
138
139 /* good read-only pages with initial offset */
140 mmap_ptr = mmap(NULL, page_size, PROT_READ, MAP_SHARED, rb_fd, page_size);
141 if (!ASSERT_OK_PTR(mmap_ptr, "ro_prod_pos"))
142 goto cleanup;
143
144 ASSERT_ERR(mprotect(mmap_ptr, page_size, PROT_WRITE), "write_protect");
145 ASSERT_ERR(mprotect(mmap_ptr, page_size, PROT_EXEC), "exec_protect");
146 ASSERT_ERR_PTR(mremap(mmap_ptr, 0, 3 * page_size, MREMAP_MAYMOVE), "ro_remap");
147 ASSERT_OK(munmap(mmap_ptr, page_size), "unmap_ro");
148
149 /* only trigger BPF program for current process */
150 skel->bss->pid = getpid();
151
152 ringbuf = ring_buffer__new(skel->maps.ringbuf.map_fd,
153 process_sample, NULL, NULL);
154 if (CHECK(!ringbuf, "ringbuf_create", "failed to create ringbuf\n"))
155 goto cleanup;
156
157 err = test_ringbuf__attach(skel);
158 if (CHECK(err, "skel_attach", "skeleton attachment failed: %d\n", err))
159 goto cleanup;
160
161 trigger_samples();
162
163 /* 2 submitted + 1 discarded records */
164 CHECK(skel->bss->avail_data != 3 * rec_sz,
165 "err_avail_size", "exp %ld, got %ld\n",
166 3L * rec_sz, skel->bss->avail_data);
167 CHECK(skel->bss->ring_size != page_size,
168 "err_ring_size", "exp %ld, got %ld\n",
169 (long)page_size, skel->bss->ring_size);
170 CHECK(skel->bss->cons_pos != 0,
171 "err_cons_pos", "exp %ld, got %ld\n",
172 0L, skel->bss->cons_pos);
173 CHECK(skel->bss->prod_pos != 3 * rec_sz,
174 "err_prod_pos", "exp %ld, got %ld\n",
175 3L * rec_sz, skel->bss->prod_pos);
176
177 /* poll for samples */
178 err = ring_buffer__poll(ringbuf, -1);
179
180 /* -EDONE is used as an indicator that we are done */
181 if (CHECK(err != -EDONE, "err_done", "done err: %d\n", err))
182 goto cleanup;
183 cnt = atomic_xchg(&sample_cnt, 0);
184 CHECK(cnt != 2, "cnt", "exp %d samples, got %d\n", 2, cnt);
185
186 /* we expect extra polling to return nothing */
187 err = ring_buffer__poll(ringbuf, 0);
188 if (CHECK(err != 0, "extra_samples", "poll result: %d\n", err))
189 goto cleanup;
190 cnt = atomic_xchg(&sample_cnt, 0);
191 CHECK(cnt != 0, "cnt", "exp %d samples, got %d\n", 0, cnt);
192
193 CHECK(skel->bss->dropped != 0, "err_dropped", "exp %ld, got %ld\n",
194 0L, skel->bss->dropped);
195 CHECK(skel->bss->total != 2, "err_total", "exp %ld, got %ld\n",
196 2L, skel->bss->total);
197 CHECK(skel->bss->discarded != 1, "err_discarded", "exp %ld, got %ld\n",
198 1L, skel->bss->discarded);
199
200 /* now validate consumer position is updated and returned */
201 trigger_samples();
202 CHECK(skel->bss->cons_pos != 3 * rec_sz,
203 "err_cons_pos", "exp %ld, got %ld\n",
204 3L * rec_sz, skel->bss->cons_pos);
205 err = ring_buffer__poll(ringbuf, -1);
206 CHECK(err <= 0, "poll_err", "err %d\n", err);
207 cnt = atomic_xchg(&sample_cnt, 0);
208 CHECK(cnt != 2, "cnt", "exp %d samples, got %d\n", 2, cnt);
209
210 /* start poll in background w/ long timeout */
211 err = pthread_create(&thread, NULL, poll_thread, (void *)(long)10000);
212 if (CHECK(err, "bg_poll", "pthread_create failed: %d\n", err))
213 goto cleanup;
214
215 /* turn off notifications now */
216 skel->bss->flags = BPF_RB_NO_WAKEUP;
217
218 /* give background thread a bit of a time */
219 usleep(50000);
220 trigger_samples();
221 /* sleeping arbitrarily is bad, but no better way to know that
222 * epoll_wait() **DID NOT** unblock in background thread
223 */
224 usleep(50000);
225 /* background poll should still be blocked */
226 err = pthread_tryjoin_np(thread, (void **)&bg_ret);
227 if (CHECK(err != EBUSY, "try_join", "err %d\n", err))
228 goto cleanup;
229
230 /* BPF side did everything right */
231 CHECK(skel->bss->dropped != 0, "err_dropped", "exp %ld, got %ld\n",
232 0L, skel->bss->dropped);
233 CHECK(skel->bss->total != 2, "err_total", "exp %ld, got %ld\n",
234 2L, skel->bss->total);
235 CHECK(skel->bss->discarded != 1, "err_discarded", "exp %ld, got %ld\n",
236 1L, skel->bss->discarded);
237 cnt = atomic_xchg(&sample_cnt, 0);
238 CHECK(cnt != 0, "cnt", "exp %d samples, got %d\n", 0, cnt);
239
240 /* clear flags to return to "adaptive" notification mode */
241 skel->bss->flags = 0;
242
243 /* produce new samples, no notification should be triggered, because
244 * consumer is now behind
245 */
246 trigger_samples();
247
248 /* background poll should still be blocked */
249 err = pthread_tryjoin_np(thread, (void **)&bg_ret);
250 if (CHECK(err != EBUSY, "try_join", "err %d\n", err))
251 goto cleanup;
252
253 /* still no samples, because consumer is behind */
254 cnt = atomic_xchg(&sample_cnt, 0);
255 CHECK(cnt != 0, "cnt", "exp %d samples, got %d\n", 0, cnt);
256
257 skel->bss->dropped = 0;
258 skel->bss->total = 0;
259 skel->bss->discarded = 0;
260
261 skel->bss->value = 333;
262 syscall(__NR_getpgid);
263 /* now force notifications */
264 skel->bss->flags = BPF_RB_FORCE_WAKEUP;
265 skel->bss->value = 777;
266 syscall(__NR_getpgid);
267
268 /* now we should get a pending notification */
269 usleep(50000);
270 err = pthread_tryjoin_np(thread, (void **)&bg_ret);
271 if (CHECK(err, "join_bg", "err %d\n", err))
272 goto cleanup;
273
274 if (CHECK(bg_ret <= 0, "bg_ret", "epoll_wait result: %ld", bg_ret))
275 goto cleanup;
276
277 /* due to timing variations, there could still be non-notified
278 * samples, so consume them here to collect all the samples
279 */
280 err = ring_buffer__consume(ringbuf);
281 CHECK(err < 0, "rb_consume", "failed: %d\b", err);
282
283 /* 3 rounds, 2 samples each */
284 cnt = atomic_xchg(&sample_cnt, 0);
285 CHECK(cnt != 6, "cnt", "exp %d samples, got %d\n", 6, cnt);
286
287 /* BPF side did everything right */
288 CHECK(skel->bss->dropped != 0, "err_dropped", "exp %ld, got %ld\n",
289 0L, skel->bss->dropped);
290 CHECK(skel->bss->total != 2, "err_total", "exp %ld, got %ld\n",
291 2L, skel->bss->total);
292 CHECK(skel->bss->discarded != 1, "err_discarded", "exp %ld, got %ld\n",
293 1L, skel->bss->discarded);
294
295 test_ringbuf__detach(skel);
296 cleanup:
297 ring_buffer__free(ringbuf);
298 test_ringbuf__destroy(skel);
299 }
300
