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.skel.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 91 skel = test_ringbuf__open_and_load(); 92 if (CHECK(!skel, "skel_open_load", "skeleton open&load failed\n")) 93 return; 94 95 /* only trigger BPF program for current process */ 96 skel->bss->pid = getpid(); 97 98 ringbuf = ring_buffer__new(bpf_map__fd(skel->maps.ringbuf), 99 process_sample, NULL, NULL); 100 if (CHECK(!ringbuf, "ringbuf_create", "failed to create ringbuf\n")) 101 goto cleanup; 102 103 err = test_ringbuf__attach(skel); 104 if (CHECK(err, "skel_attach", "skeleton attachment failed: %d\n", err)) 105 goto cleanup; 106 107 trigger_samples(); 108 109 /* 2 submitted + 1 discarded records */ 110 CHECK(skel->bss->avail_data != 3 * rec_sz, 111 "err_avail_size", "exp %ld, got %ld\n", 112 3L * rec_sz, skel->bss->avail_data); 113 CHECK(skel->bss->ring_size != 4096, 114 "err_ring_size", "exp %ld, got %ld\n", 115 4096L, skel->bss->ring_size); 116 CHECK(skel->bss->cons_pos != 0, 117 "err_cons_pos", "exp %ld, got %ld\n", 118 0L, skel->bss->cons_pos); 119 CHECK(skel->bss->prod_pos != 3 * rec_sz, 120 "err_prod_pos", "exp %ld, got %ld\n", 121 3L * rec_sz, skel->bss->prod_pos); 122 123 /* poll for samples */ 124 err = ring_buffer__poll(ringbuf, -1); 125 126 /* -EDONE is used as an indicator that we are done */ 127 if (CHECK(err != -EDONE, "err_done", "done err: %d\n", err)) 128 goto cleanup; 129 cnt = atomic_xchg(&sample_cnt, 0); 130 CHECK(cnt != 2, "cnt", "exp %d samples, got %d\n", 2, cnt); 131 132 /* we expect extra polling to return nothing */ 133 err = ring_buffer__poll(ringbuf, 0); 134 if (CHECK(err != 0, "extra_samples", "poll result: %d\n", err)) 135 goto cleanup; 136 cnt = atomic_xchg(&sample_cnt, 0); 137 CHECK(cnt != 0, "cnt", "exp %d samples, got %d\n", 0, cnt); 138 139 CHECK(skel->bss->dropped != 0, "err_dropped", "exp %ld, got %ld\n", 140 0L, skel->bss->dropped); 141 CHECK(skel->bss->total != 2, "err_total", "exp %ld, got %ld\n", 142 2L, skel->bss->total); 143 CHECK(skel->bss->discarded != 1, "err_discarded", "exp %ld, got %ld\n", 144 1L, skel->bss->discarded); 145 146 /* now validate consumer position is updated and returned */ 147 trigger_samples(); 148 CHECK(skel->bss->cons_pos != 3 * rec_sz, 149 "err_cons_pos", "exp %ld, got %ld\n", 150 3L * rec_sz, skel->bss->cons_pos); 151 err = ring_buffer__poll(ringbuf, -1); 152 CHECK(err <= 0, "poll_err", "err %d\n", err); 153 cnt = atomic_xchg(&sample_cnt, 0); 154 CHECK(cnt != 2, "cnt", "exp %d samples, got %d\n", 2, cnt); 155 156 /* start poll in background w/ long timeout */ 157 err = pthread_create(&thread, NULL, poll_thread, (void *)(long)10000); 158 if (CHECK(err, "bg_poll", "pthread_create failed: %d\n", err)) 159 goto cleanup; 160 161 /* turn off notifications now */ 162 skel->bss->flags = BPF_RB_NO_WAKEUP; 163 164 /* give background thread a bit of a time */ 165 usleep(50000); 166 trigger_samples(); 167 /* sleeping arbitrarily is bad, but no better way to know that 168 * epoll_wait() **DID NOT** unblock in background thread 169 */ 170 usleep(50000); 171 /* background poll should still be blocked */ 172 err = pthread_tryjoin_np(thread, (void **)&bg_ret); 173 if (CHECK(err != EBUSY, "try_join", "err %d\n", err)) 174 goto cleanup; 175 176 /* BPF side did everything right */ 177 CHECK(skel->bss->dropped != 0, "err_dropped", "exp %ld, got %ld\n", 178 0L, skel->bss->dropped); 179 CHECK(skel->bss->total != 2, "err_total", "exp %ld, got %ld\n", 180 2L, skel->bss->total); 181 CHECK(skel->bss->discarded != 1, "err_discarded", "exp %ld, got %ld\n", 182 1L, skel->bss->discarded); 183 cnt = atomic_xchg(&sample_cnt, 0); 184 CHECK(cnt != 0, "cnt", "exp %d samples, got %d\n", 0, cnt); 185 186 /* clear flags to return to "adaptive" notification mode */ 187 skel->bss->flags = 0; 188 189 /* produce new samples, no notification should be triggered, because 190 * consumer is now behind 191 */ 192 trigger_samples(); 193 194 /* background poll should still be blocked */ 195 err = pthread_tryjoin_np(thread, (void **)&bg_ret); 196 if (CHECK(err != EBUSY, "try_join", "err %d\n", err)) 197 goto cleanup; 198 199 /* still no samples, because consumer is behind */ 200 cnt = atomic_xchg(&sample_cnt, 0); 201 CHECK(cnt != 0, "cnt", "exp %d samples, got %d\n", 0, cnt); 202 203 skel->bss->dropped = 0; 204 skel->bss->total = 0; 205 skel->bss->discarded = 0; 206 207 skel->bss->value = 333; 208 syscall(__NR_getpgid); 209 /* now force notifications */ 210 skel->bss->flags = BPF_RB_FORCE_WAKEUP; 211 skel->bss->value = 777; 212 syscall(__NR_getpgid); 213 214 /* now we should get a pending notification */ 215 usleep(50000); 216 err = pthread_tryjoin_np(thread, (void **)&bg_ret); 217 if (CHECK(err, "join_bg", "err %d\n", err)) 218 goto cleanup; 219 220 if (CHECK(bg_ret != 1, "bg_ret", "epoll_wait result: %ld", bg_ret)) 221 goto cleanup; 222 223 /* 3 rounds, 2 samples each */ 224 cnt = atomic_xchg(&sample_cnt, 0); 225 CHECK(cnt != 6, "cnt", "exp %d samples, got %d\n", 6, cnt); 226 227 /* BPF side did everything right */ 228 CHECK(skel->bss->dropped != 0, "err_dropped", "exp %ld, got %ld\n", 229 0L, skel->bss->dropped); 230 CHECK(skel->bss->total != 2, "err_total", "exp %ld, got %ld\n", 231 2L, skel->bss->total); 232 CHECK(skel->bss->discarded != 1, "err_discarded", "exp %ld, got %ld\n", 233 1L, skel->bss->discarded); 234 235 test_ringbuf__detach(skel); 236 cleanup: 237 ring_buffer__free(ringbuf); 238 test_ringbuf__destroy(skel); 239 } 240