selftests/bpf: Add BPF ringbuf selftests

Both singleton BPF ringbuf and BPF ringbuf with map-in-map use cases are tested.
Also reserve+submit/discards and output variants of API are validated.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200529075424.3139988-4-andriin@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/tools/testing/selftests/bpf/prog_tests/ringbuf.c b/tools/testing/selftests/bpf/prog_tests/ringbuf.c
new file mode 100644 (file)
index 0000000..bb8541f
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/ringbuf.c
@@ -0,0 +1,211 @@
+// 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 int process_sample(void *ctx, void *data, size_t len)
+{
+       struct sample *s = data;
+
+       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;
+
+       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;
+
+       /* 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;
+
+       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);
+
+       /* 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);
+
+       /* 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;
+
+       /* now force notifications */
+       skel->bss->flags = BPF_RB_FORCE_WAKEUP;
+       sample_cnt = 0;
+       trigger_samples();
+
+       /* 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 */
+       CHECK(sample_cnt != 6, "wrong_sample_cnt",
+             "expected to see %d samples, got %d\n", 6, sample_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);
+}

diff --git a/tools/testing/selftests/bpf/prog_tests/ringbuf_multi.c b/tools/testing/selftests/bpf/prog_tests/ringbuf_multi.c
new file mode 100644 (file)
index 0000000..78e4506
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/ringbuf_multi.c
@@ -0,0 +1,102 @@
+// SPDX-License-Identifier: GPL-2.0
+#define _GNU_SOURCE
+#include <test_progs.h>
+#include <sys/epoll.h>
+#include "test_ringbuf_multi.skel.h"
+
+static int duration = 0;
+
+struct sample {
+       int pid;
+       int seq;
+       long value;
+       char comm[16];
+};
+
+static int process_sample(void *ctx, void *data, size_t len)
+{
+       int ring = (unsigned long)ctx;
+       struct sample *s = data;
+
+       switch (s->seq) {
+       case 0:
+               CHECK(ring != 1, "sample1_ring", "exp %d, got %d\n", 1, ring);
+               CHECK(s->value != 333, "sample1_value", "exp %ld, got %ld\n",
+                     333L, s->value);
+               break;
+       case 1:
+               CHECK(ring != 2, "sample2_ring", "exp %d, got %d\n", 2, ring);
+               CHECK(s->value != 777, "sample2_value", "exp %ld, got %ld\n",
+                     777L, s->value);
+               break;
+       default:
+               CHECK(true, "extra_sample", "unexpected sample seq %d, val %ld\n",
+                     s->seq, s->value);
+               return -1;
+       }
+
+       return 0;
+}
+
+void test_ringbuf_multi(void)
+{
+       struct test_ringbuf_multi *skel;
+       struct ring_buffer *ringbuf;
+       int err;
+
+       skel = test_ringbuf_multi__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.ringbuf1),
+                                  process_sample, (void *)(long)1, NULL);
+       if (CHECK(!ringbuf, "ringbuf_create", "failed to create ringbuf\n"))
+               goto cleanup;
+
+       err = ring_buffer__add(ringbuf, bpf_map__fd(skel->maps.ringbuf2),
+                             process_sample, (void *)(long)2);
+       if (CHECK(err, "ringbuf_add", "failed to add another ring\n"))
+               goto cleanup;
+
+       err = test_ringbuf_multi__attach(skel);
+       if (CHECK(err, "skel_attach", "skeleton attachment failed: %d\n", err))
+               goto cleanup;
+
+       /* trigger few samples, some will be skipped */
+       skel->bss->target_ring = 0;
+       skel->bss->value = 333;
+       syscall(__NR_getpgid);
+
+       /* skipped, no ringbuf in slot 1 */
+       skel->bss->target_ring = 1;
+       skel->bss->value = 555;
+       syscall(__NR_getpgid);
+
+       skel->bss->target_ring = 2;
+       skel->bss->value = 777;
+       syscall(__NR_getpgid);
+
+       /* poll for samples, should get 2 ringbufs back */
+       err = ring_buffer__poll(ringbuf, -1);
+       if (CHECK(err != 4, "poll_res", "expected 4 records, got %d\n", err))
+               goto cleanup;
+
+       /* 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;
+
+       CHECK(skel->bss->dropped != 0, "err_dropped", "exp %ld, got %ld\n",
+             0L, skel->bss->dropped);
+       CHECK(skel->bss->skipped != 1, "err_skipped", "exp %ld, got %ld\n",
+             1L, skel->bss->skipped);
+       CHECK(skel->bss->total != 2, "err_total", "exp %ld, got %ld\n",
+             2L, skel->bss->total);
+
+cleanup:
+       ring_buffer__free(ringbuf);
+       test_ringbuf_multi__destroy(skel);
+}

diff --git a/tools/testing/selftests/bpf/progs/test_ringbuf.c b/tools/testing/selftests/bpf/progs/test_ringbuf.c
new file mode 100644 (file)
index 0000000..8ba9959
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_ringbuf.c
@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2020 Facebook
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+char _license[] SEC("license") = "GPL";
+
+struct sample {
+       int pid;
+       int seq;
+       long value;
+       char comm[16];
+};
+
+struct {
+       __uint(type, BPF_MAP_TYPE_RINGBUF);
+       __uint(max_entries, 1 << 12);
+} ringbuf SEC(".maps");
+
+/* inputs */
+int pid = 0;
+long value = 0;
+long flags = 0;
+
+/* outputs */
+long total = 0;
+long discarded = 0;
+long dropped = 0;
+
+long avail_data = 0;
+long ring_size = 0;
+long cons_pos = 0;
+long prod_pos = 0;
+
+/* inner state */
+long seq = 0;
+
+SEC("tp/syscalls/sys_enter_getpgid")
+int test_ringbuf(void *ctx)
+{
+       int cur_pid = bpf_get_current_pid_tgid() >> 32;
+       struct sample *sample;
+       int zero = 0;
+
+       if (cur_pid != pid)
+               return 0;
+
+       sample = bpf_ringbuf_reserve(&ringbuf, sizeof(*sample), 0);
+       if (!sample) {
+               __sync_fetch_and_add(&dropped, 1);
+               return 1;
+       }
+
+       sample->pid = pid;
+       bpf_get_current_comm(sample->comm, sizeof(sample->comm));
+       sample->value = value;
+
+       sample->seq = seq++;
+       __sync_fetch_and_add(&total, 1);
+
+       if (sample->seq & 1) {
+               /* copy from reserved sample to a new one... */
+               bpf_ringbuf_output(&ringbuf, sample, sizeof(*sample), flags);
+               /* ...and then discard reserved sample */
+               bpf_ringbuf_discard(sample, flags);
+               __sync_fetch_and_add(&discarded, 1);
+       } else {
+               bpf_ringbuf_submit(sample, flags);
+       }
+
+       avail_data = bpf_ringbuf_query(&ringbuf, BPF_RB_AVAIL_DATA);
+       ring_size = bpf_ringbuf_query(&ringbuf, BPF_RB_RING_SIZE);
+       cons_pos = bpf_ringbuf_query(&ringbuf, BPF_RB_CONS_POS);
+       prod_pos = bpf_ringbuf_query(&ringbuf, BPF_RB_PROD_POS);
+
+       return 0;
+}

diff --git a/tools/testing/selftests/bpf/progs/test_ringbuf_multi.c b/tools/testing/selftests/bpf/progs/test_ringbuf_multi.c
new file mode 100644 (file)
index 0000000..edf3b69
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_ringbuf_multi.c
@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2020 Facebook
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+char _license[] SEC("license") = "GPL";
+
+struct sample {
+       int pid;
+       int seq;
+       long value;
+       char comm[16];
+};
+
+struct ringbuf_map {
+       __uint(type, BPF_MAP_TYPE_RINGBUF);
+       __uint(max_entries, 1 << 12);
+} ringbuf1 SEC(".maps"),
+  ringbuf2 SEC(".maps");
+
+struct {
+       __uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
+       __uint(max_entries, 4);
+       __type(key, int);
+       __array(values, struct ringbuf_map);
+} ringbuf_arr SEC(".maps") = {
+       .values = {
+               [0] = &ringbuf1,
+               [2] = &ringbuf2,
+       },
+};
+
+/* inputs */
+int pid = 0;
+int target_ring = 0;
+long value = 0;
+
+/* outputs */
+long total = 0;
+long dropped = 0;
+long skipped = 0;
+
+SEC("tp/syscalls/sys_enter_getpgid")
+int test_ringbuf(void *ctx)
+{
+       int cur_pid = bpf_get_current_pid_tgid() >> 32;
+       struct sample *sample;
+       void *rb;
+       int zero = 0;
+
+       if (cur_pid != pid)
+               return 0;
+
+       rb = bpf_map_lookup_elem(&ringbuf_arr, &target_ring);
+       if (!rb) {
+               skipped += 1;
+               return 1;
+       }
+
+       sample = bpf_ringbuf_reserve(rb, sizeof(*sample), 0);
+       if (!sample) {
+               dropped += 1;
+               return 1;
+       }
+
+       sample->pid = pid;
+       bpf_get_current_comm(sample->comm, sizeof(sample->comm));
+       sample->value = value;
+
+       sample->seq = total;
+       total += 1;
+
+       bpf_ringbuf_submit(sample, 0);
+
+       return 0;
+}