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 30 static void atomic_inc(int *cnt) 31 { 32 __atomic_add_fetch(cnt, 1, __ATOMIC_SEQ_CST); 33 } 34 35 static int atomic_xchg(int *cnt, int val) 36 { 37 return __atomic_exchange_n(cnt, val, __ATOMIC_SEQ_CST); 38 } 39 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 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 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 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; 90 int page_size = getpagesize(); 91 92 skel = test_ringbuf__open(); 93 if (CHECK(!skel, "skel_open", "skeleton open failed\n")) 94 return; 95 96 skel->maps.ringbuf.max_entries = page_size; 97 98 err = test_ringbuf__load(skel); 99 if (CHECK(err != 0, "skel_load", "skeleton load failed\n")) 100 goto cleanup; 101 102 /* only trigger BPF program for current process */ 103 skel->bss->pid = getpid(); 104 105 ringbuf = ring_buffer__new(skel->maps.ringbuf.map_fd, 106 process_sample, NULL, NULL); 107 if (CHECK(!ringbuf, "ringbuf_create", "failed to create ringbuf\n")) 108 goto cleanup; 109 110 err = test_ringbuf__attach(skel); 111 if (CHECK(err, "skel_attach", "skeleton attachment failed: %d\n", err)) 112 goto cleanup; 113 114 trigger_samples(); 115 116 /* 2 submitted + 1 discarded records */ 117 CHECK(skel->bss->avail_data != 3 * rec_sz, 118 "err_avail_size", "exp %ld, got %ld\n", 119 3L * rec_sz, skel->bss->avail_data); 120 CHECK(skel->bss->ring_size != page_size, 121 "err_ring_size", "exp %ld, got %ld\n", 122 (long)page_size, skel->bss->ring_size); 123 CHECK(skel->bss->cons_pos != 0, 124 "err_cons_pos", "exp %ld, got %ld\n", 125 0L, skel->bss->cons_pos); 126 CHECK(skel->bss->prod_pos != 3 * rec_sz, 127 "err_prod_pos", "exp %ld, got %ld\n", 128 3L * rec_sz, skel->bss->prod_pos); 129 130 /* poll for samples */ 131 err = ring_buffer__poll(ringbuf, -1); 132 133 /* -EDONE is used as an indicator that we are done */ 134 if (CHECK(err != -EDONE, "err_done", "done err: %d\n", err)) 135 goto cleanup; 136 cnt = atomic_xchg(&sample_cnt, 0); 137 CHECK(cnt != 2, "cnt", "exp %d samples, got %d\n", 2, cnt); 138 139 /* we expect extra polling to return nothing */ 140 err = ring_buffer__poll(ringbuf, 0); 141 if (CHECK(err != 0, "extra_samples", "poll result: %d\n", err)) 142 goto cleanup; 143 cnt = atomic_xchg(&sample_cnt, 0); 144 CHECK(cnt != 0, "cnt", "exp %d samples, got %d\n", 0, cnt); 145 146 CHECK(skel->bss->dropped != 0, "err_dropped", "exp %ld, got %ld\n", 147 0L, skel->bss->dropped); 148 CHECK(skel->bss->total != 2, "err_total", "exp %ld, got %ld\n", 149 2L, skel->bss->total); 150 CHECK(skel->bss->discarded != 1, "err_discarded", "exp %ld, got %ld\n", 151 1L, skel->bss->discarded); 152 153 /* now validate consumer position is updated and returned */ 154 trigger_samples(); 155 CHECK(skel->bss->cons_pos != 3 * rec_sz, 156 "err_cons_pos", "exp %ld, got %ld\n", 157 3L * rec_sz, skel->bss->cons_pos); 158 err = ring_buffer__poll(ringbuf, -1); 159 CHECK(err <= 0, "poll_err", "err %d\n", err); 160 cnt = atomic_xchg(&sample_cnt, 0); 161 CHECK(cnt != 2, "cnt", "exp %d samples, got %d\n", 2, cnt); 162 163 /* start poll in background w/ long timeout */ 164 err = pthread_create(&thread, NULL, poll_thread, (void *)(long)10000); 165 if (CHECK(err, "bg_poll", "pthread_create failed: %d\n", err)) 166 goto cleanup; 167 168 /* turn off notifications now */ 169 skel->bss->flags = BPF_RB_NO_WAKEUP; 170 171 /* give background thread a bit of a time */ 172 usleep(50000); 173 trigger_samples(); 174 /* sleeping arbitrarily is bad, but no better way to know that 175 * epoll_wait() **DID NOT** unblock in background thread 176 */ 177 usleep(50000); 178 /* background poll should still be blocked */ 179 err = pthread_tryjoin_np(thread, (void **)&bg_ret); 180 if (CHECK(err != EBUSY, "try_join", "err %d\n", err)) 181 goto cleanup; 182 183 /* BPF side did everything right */ 184 CHECK(skel->bss->dropped != 0, "err_dropped", "exp %ld, got %ld\n", 185 0L, skel->bss->dropped); 186 CHECK(skel->bss->total != 2, "err_total", "exp %ld, got %ld\n", 187 2L, skel->bss->total); 188 CHECK(skel->bss->discarded != 1, "err_discarded", "exp %ld, got %ld\n", 189 1L, skel->bss->discarded); 190 cnt = atomic_xchg(&sample_cnt, 0); 191 CHECK(cnt != 0, "cnt", "exp %d samples, got %d\n", 0, cnt); 192 193 /* clear flags to return to "adaptive" notification mode */ 194 skel->bss->flags = 0; 195 196 /* produce new samples, no notification should be triggered, because 197 * consumer is now behind 198 */ 199 trigger_samples(); 200 201 /* background poll should still be blocked */ 202 err = pthread_tryjoin_np(thread, (void **)&bg_ret); 203 if (CHECK(err != EBUSY, "try_join", "err %d\n", err)) 204 goto cleanup; 205 206 /* still no samples, because consumer is behind */ 207 cnt = atomic_xchg(&sample_cnt, 0); 208 CHECK(cnt != 0, "cnt", "exp %d samples, got %d\n", 0, cnt); 209 210 skel->bss->dropped = 0; 211 skel->bss->total = 0; 212 skel->bss->discarded = 0; 213 214 skel->bss->value = 333; 215 syscall(__NR_getpgid); 216 /* now force notifications */ 217 skel->bss->flags = BPF_RB_FORCE_WAKEUP; 218 skel->bss->value = 777; 219 syscall(__NR_getpgid); 220 221 /* now we should get a pending notification */ 222 usleep(50000); 223 err = pthread_tryjoin_np(thread, (void **)&bg_ret); 224 if (CHECK(err, "join_bg", "err %d\n", err)) 225 goto cleanup; 226 227 if (CHECK(bg_ret <= 0, "bg_ret", "epoll_wait result: %ld", bg_ret)) 228 goto cleanup; 229 230 /* due to timing variations, there could still be non-notified 231 * samples, so consume them here to collect all the samples 232 */ 233 err = ring_buffer__consume(ringbuf); 234 CHECK(err < 0, "rb_consume", "failed: %d\b", err); 235 236 /* 3 rounds, 2 samples each */ 237 cnt = atomic_xchg(&sample_cnt, 0); 238 CHECK(cnt != 6, "cnt", "exp %d samples, got %d\n", 6, cnt); 239 240 /* BPF side did everything right */ 241 CHECK(skel->bss->dropped != 0, "err_dropped", "exp %ld, got %ld\n", 242 0L, skel->bss->dropped); 243 CHECK(skel->bss->total != 2, "err_total", "exp %ld, got %ld\n", 244 2L, skel->bss->total); 245 CHECK(skel->bss->discarded != 1, "err_discarded", "exp %ld, got %ld\n", 246 1L, skel->bss->discarded); 247 248 test_ringbuf__detach(skel); 249 cleanup: 250 ring_buffer__free(ringbuf); 251 test_ringbuf__destroy(skel); 252 } 253