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-rw-r--r--tools/testing/selftests/bpf/prog_tests/ringbuf.c211
1 files changed, 211 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/ringbuf.c b/tools/testing/selftests/bpf/prog_tests/ringbuf.c
new file mode 100644
index 000000000000..2bba908dfa63
--- /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 volatile 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);
+}
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