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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 | // SPDX-License-Identifier: GPL-2.0 #define _GNU_SOURCE #include <linux/compiler.h> #include <asm/barrier.h> #include <test_progs.h> #include <sys/mman.h> #include <sys/epoll.h> #include <time.h> #include <sched.h> #include <signal.h> #include <pthread.h> #include <sys/sysinfo.h> #include <linux/perf_event.h> #include <linux/ring_buffer.h> #include "test_ringbuf.skel.h" #define EDONE 7777 static int duration = 0; struct sample { int pid; int seq; long value; char comm[16]; }; static int sample_cnt; static void atomic_inc(int *cnt) { __atomic_add_fetch(cnt, 1, __ATOMIC_SEQ_CST); } static int atomic_xchg(int *cnt, int val) { return __atomic_exchange_n(cnt, val, __ATOMIC_SEQ_CST); } static int process_sample(void *ctx, void *data, size_t len) { struct sample *s = data; atomic_inc(&sample_cnt); switch (s->seq) { case 0: CHECK(s->value != 333, "sample1_value", "exp %ld, got %ld\n", 333L, s->value); return 0; case 1: CHECK(s->value != 777, "sample2_value", "exp %ld, got %ld\n", 777L, s->value); return -EDONE; default: /* we don't care about the rest */ return 0; } } static struct test_ringbuf *skel; static struct ring_buffer *ringbuf; static void trigger_samples() { skel->bss->dropped = 0; skel->bss->total = 0; skel->bss->discarded = 0; /* trigger exactly two samples */ skel->bss->value = 333; syscall(__NR_getpgid); skel->bss->value = 777; syscall(__NR_getpgid); } static void *poll_thread(void *input) { long timeout = (long)input; return (void *)(long)ring_buffer__poll(ringbuf, timeout); } void test_ringbuf(void) { const size_t rec_sz = BPF_RINGBUF_HDR_SZ + sizeof(struct sample); pthread_t thread; long bg_ret = -1; int err, cnt; skel = test_ringbuf__open_and_load(); if (CHECK(!skel, "skel_open_load", "skeleton open&load failed\n")) return; /* only trigger BPF program for current process */ skel->bss->pid = getpid(); ringbuf = ring_buffer__new(bpf_map__fd(skel->maps.ringbuf), process_sample, NULL, NULL); if (CHECK(!ringbuf, "ringbuf_create", "failed to create ringbuf\n")) goto cleanup; err = test_ringbuf__attach(skel); if (CHECK(err, "skel_attach", "skeleton attachment failed: %d\n", err)) goto cleanup; trigger_samples(); /* 2 submitted + 1 discarded records */ CHECK(skel->bss->avail_data != 3 * rec_sz, "err_avail_size", "exp %ld, got %ld\n", 3L * rec_sz, skel->bss->avail_data); CHECK(skel->bss->ring_size != 4096, "err_ring_size", "exp %ld, got %ld\n", 4096L, skel->bss->ring_size); CHECK(skel->bss->cons_pos != 0, "err_cons_pos", "exp %ld, got %ld\n", 0L, skel->bss->cons_pos); CHECK(skel->bss->prod_pos != 3 * rec_sz, "err_prod_pos", "exp %ld, got %ld\n", 3L * rec_sz, skel->bss->prod_pos); /* poll for samples */ err = ring_buffer__poll(ringbuf, -1); /* -EDONE is used as an indicator that we are done */ if (CHECK(err != -EDONE, "err_done", "done err: %d\n", err)) goto cleanup; cnt = atomic_xchg(&sample_cnt, 0); CHECK(cnt != 2, "cnt", "exp %d samples, got %d\n", 2, cnt); /* we expect extra polling to return nothing */ err = ring_buffer__poll(ringbuf, 0); if (CHECK(err != 0, "extra_samples", "poll result: %d\n", err)) goto cleanup; cnt = atomic_xchg(&sample_cnt, 0); CHECK(cnt != 0, "cnt", "exp %d samples, got %d\n", 0, cnt); CHECK(skel->bss->dropped != 0, "err_dropped", "exp %ld, got %ld\n", 0L, skel->bss->dropped); CHECK(skel->bss->total != 2, "err_total", "exp %ld, got %ld\n", 2L, skel->bss->total); CHECK(skel->bss->discarded != 1, "err_discarded", "exp %ld, got %ld\n", 1L, skel->bss->discarded); /* now validate consumer position is updated and returned */ trigger_samples(); CHECK(skel->bss->cons_pos != 3 * rec_sz, "err_cons_pos", "exp %ld, got %ld\n", 3L * rec_sz, skel->bss->cons_pos); err = ring_buffer__poll(ringbuf, -1); CHECK(err <= 0, "poll_err", "err %d\n", err); cnt = atomic_xchg(&sample_cnt, 0); CHECK(cnt != 2, "cnt", "exp %d samples, got %d\n", 2, cnt); /* start poll in background w/ long timeout */ err = pthread_create(&thread, NULL, poll_thread, (void *)(long)10000); if (CHECK(err, "bg_poll", "pthread_create failed: %d\n", err)) goto cleanup; /* turn off notifications now */ skel->bss->flags = BPF_RB_NO_WAKEUP; /* give background thread a bit of a time */ usleep(50000); trigger_samples(); /* sleeping arbitrarily is bad, but no better way to know that * epoll_wait() **DID NOT** unblock in background thread */ usleep(50000); /* background poll should still be blocked */ err = pthread_tryjoin_np(thread, (void **)&bg_ret); if (CHECK(err != EBUSY, "try_join", "err %d\n", err)) goto cleanup; /* BPF side did everything right */ CHECK(skel->bss->dropped != 0, "err_dropped", "exp %ld, got %ld\n", 0L, skel->bss->dropped); CHECK(skel->bss->total != 2, "err_total", "exp %ld, got %ld\n", 2L, skel->bss->total); CHECK(skel->bss->discarded != 1, "err_discarded", "exp %ld, got %ld\n", 1L, skel->bss->discarded); cnt = atomic_xchg(&sample_cnt, 0); CHECK(cnt != 0, "cnt", "exp %d samples, got %d\n", 0, cnt); /* clear flags to return to "adaptive" notification mode */ skel->bss->flags = 0; /* produce new samples, no notification should be triggered, because * consumer is now behind */ trigger_samples(); /* background poll should still be blocked */ err = pthread_tryjoin_np(thread, (void **)&bg_ret); if (CHECK(err != EBUSY, "try_join", "err %d\n", err)) goto cleanup; /* still no samples, because consumer is behind */ cnt = atomic_xchg(&sample_cnt, 0); CHECK(cnt != 0, "cnt", "exp %d samples, got %d\n", 0, cnt); skel->bss->dropped = 0; skel->bss->total = 0; skel->bss->discarded = 0; skel->bss->value = 333; syscall(__NR_getpgid); /* now force notifications */ skel->bss->flags = BPF_RB_FORCE_WAKEUP; skel->bss->value = 777; syscall(__NR_getpgid); /* now we should get a pending notification */ usleep(50000); err = pthread_tryjoin_np(thread, (void **)&bg_ret); if (CHECK(err, "join_bg", "err %d\n", err)) goto cleanup; if (CHECK(bg_ret != 1, "bg_ret", "epoll_wait result: %ld", bg_ret)) goto cleanup; /* 3 rounds, 2 samples each */ cnt = atomic_xchg(&sample_cnt, 0); CHECK(cnt != 6, "cnt", "exp %d samples, got %d\n", 6, cnt); /* BPF side did everything right */ CHECK(skel->bss->dropped != 0, "err_dropped", "exp %ld, got %ld\n", 0L, skel->bss->dropped); CHECK(skel->bss->total != 2, "err_total", "exp %ld, got %ld\n", 2L, skel->bss->total); CHECK(skel->bss->discarded != 1, "err_discarded", "exp %ld, got %ld\n", 1L, skel->bss->discarded); test_ringbuf__detach(skel); cleanup: ring_buffer__free(ringbuf); test_ringbuf__destroy(skel); } |