300 lines
		
	
	
		
			9.1 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			300 lines
		
	
	
		
			9.1 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
// SPDX-License-Identifier: GPL-2.0
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#define _GNU_SOURCE
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#include <linux/compiler.h>
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#include <asm/barrier.h>
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#include <test_progs.h>
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#include <sys/mman.h>
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#include <sys/epoll.h>
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#include <time.h>
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#include <sched.h>
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#include <signal.h>
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#include <pthread.h>
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#include <sys/sysinfo.h>
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#include <linux/perf_event.h>
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#include <linux/ring_buffer.h>
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#include "test_ringbuf.lskel.h"
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#define EDONE 7777
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static int duration = 0;
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struct sample {
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	int pid;
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	int seq;
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	long value;
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	char comm[16];
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};
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static int sample_cnt;
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static void atomic_inc(int *cnt)
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{
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	__atomic_add_fetch(cnt, 1, __ATOMIC_SEQ_CST);
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}
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static int atomic_xchg(int *cnt, int val)
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{
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	return __atomic_exchange_n(cnt, val, __ATOMIC_SEQ_CST);
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}
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static int process_sample(void *ctx, void *data, size_t len)
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{
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	struct sample *s = data;
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	atomic_inc(&sample_cnt);
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	switch (s->seq) {
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	case 0:
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		CHECK(s->value != 333, "sample1_value", "exp %ld, got %ld\n",
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		      333L, s->value);
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		return 0;
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	case 1:
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		CHECK(s->value != 777, "sample2_value", "exp %ld, got %ld\n",
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		      777L, s->value);
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		return -EDONE;
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	default:
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		/* we don't care about the rest */
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		return 0;
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	}
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}
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static struct test_ringbuf_lskel *skel;
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static struct ring_buffer *ringbuf;
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static void trigger_samples()
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{
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	skel->bss->dropped = 0;
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	skel->bss->total = 0;
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	skel->bss->discarded = 0;
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	/* trigger exactly two samples */
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	skel->bss->value = 333;
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	syscall(__NR_getpgid);
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	skel->bss->value = 777;
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	syscall(__NR_getpgid);
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}
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static void *poll_thread(void *input)
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{
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	long timeout = (long)input;
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	return (void *)(long)ring_buffer__poll(ringbuf, timeout);
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}
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void test_ringbuf(void)
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{
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	const size_t rec_sz = BPF_RINGBUF_HDR_SZ + sizeof(struct sample);
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	pthread_t thread;
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	long bg_ret = -1;
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	int err, cnt, rb_fd;
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	int page_size = getpagesize();
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	void *mmap_ptr, *tmp_ptr;
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	skel = test_ringbuf_lskel__open();
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	if (CHECK(!skel, "skel_open", "skeleton open failed\n"))
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		return;
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	skel->maps.ringbuf.max_entries = page_size;
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	err = test_ringbuf_lskel__load(skel);
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	if (CHECK(err != 0, "skel_load", "skeleton load failed\n"))
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		goto cleanup;
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	rb_fd = skel->maps.ringbuf.map_fd;
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	/* good read/write cons_pos */
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	mmap_ptr = mmap(NULL, page_size, PROT_READ | PROT_WRITE, MAP_SHARED, rb_fd, 0);
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	ASSERT_OK_PTR(mmap_ptr, "rw_cons_pos");
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	tmp_ptr = mremap(mmap_ptr, page_size, 2 * page_size, MREMAP_MAYMOVE);
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	if (!ASSERT_ERR_PTR(tmp_ptr, "rw_extend"))
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		goto cleanup;
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	ASSERT_ERR(mprotect(mmap_ptr, page_size, PROT_EXEC), "exec_cons_pos_protect");
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	ASSERT_OK(munmap(mmap_ptr, page_size), "unmap_rw");
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	/* bad writeable prod_pos */
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	mmap_ptr = mmap(NULL, page_size, PROT_WRITE, MAP_SHARED, rb_fd, page_size);
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	err = -errno;
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	ASSERT_ERR_PTR(mmap_ptr, "wr_prod_pos");
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	ASSERT_EQ(err, -EPERM, "wr_prod_pos_err");
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	/* bad writeable data pages */
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	mmap_ptr = mmap(NULL, page_size, PROT_WRITE, MAP_SHARED, rb_fd, 2 * page_size);
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	err = -errno;
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	ASSERT_ERR_PTR(mmap_ptr, "wr_data_page_one");
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	ASSERT_EQ(err, -EPERM, "wr_data_page_one_err");
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	mmap_ptr = mmap(NULL, page_size, PROT_WRITE, MAP_SHARED, rb_fd, 3 * page_size);
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	ASSERT_ERR_PTR(mmap_ptr, "wr_data_page_two");
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	mmap_ptr = mmap(NULL, 2 * page_size, PROT_WRITE, MAP_SHARED, rb_fd, 2 * page_size);
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	ASSERT_ERR_PTR(mmap_ptr, "wr_data_page_all");
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	/* good read-only pages */
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	mmap_ptr = mmap(NULL, 4 * page_size, PROT_READ, MAP_SHARED, rb_fd, 0);
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	if (!ASSERT_OK_PTR(mmap_ptr, "ro_prod_pos"))
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		goto cleanup;
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	ASSERT_ERR(mprotect(mmap_ptr, 4 * page_size, PROT_WRITE), "write_protect");
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	ASSERT_ERR(mprotect(mmap_ptr, 4 * page_size, PROT_EXEC), "exec_protect");
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	ASSERT_ERR_PTR(mremap(mmap_ptr, 0, 4 * page_size, MREMAP_MAYMOVE), "ro_remap");
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	ASSERT_OK(munmap(mmap_ptr, 4 * page_size), "unmap_ro");
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	/* good read-only pages with initial offset */
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	mmap_ptr = mmap(NULL, page_size, PROT_READ, MAP_SHARED, rb_fd, page_size);
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	if (!ASSERT_OK_PTR(mmap_ptr, "ro_prod_pos"))
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		goto cleanup;
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	ASSERT_ERR(mprotect(mmap_ptr, page_size, PROT_WRITE), "write_protect");
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	ASSERT_ERR(mprotect(mmap_ptr, page_size, PROT_EXEC), "exec_protect");
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	ASSERT_ERR_PTR(mremap(mmap_ptr, 0, 3 * page_size, MREMAP_MAYMOVE), "ro_remap");
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	ASSERT_OK(munmap(mmap_ptr, page_size), "unmap_ro");
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	/* only trigger BPF program for current process */
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	skel->bss->pid = getpid();
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	ringbuf = ring_buffer__new(skel->maps.ringbuf.map_fd,
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				   process_sample, NULL, NULL);
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	if (CHECK(!ringbuf, "ringbuf_create", "failed to create ringbuf\n"))
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		goto cleanup;
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	err = test_ringbuf_lskel__attach(skel);
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	if (CHECK(err, "skel_attach", "skeleton attachment failed: %d\n", err))
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		goto cleanup;
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	trigger_samples();
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	/* 2 submitted + 1 discarded records */
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	CHECK(skel->bss->avail_data != 3 * rec_sz,
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	      "err_avail_size", "exp %ld, got %ld\n",
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	      3L * rec_sz, skel->bss->avail_data);
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	CHECK(skel->bss->ring_size != page_size,
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	      "err_ring_size", "exp %ld, got %ld\n",
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	      (long)page_size, skel->bss->ring_size);
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	CHECK(skel->bss->cons_pos != 0,
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	      "err_cons_pos", "exp %ld, got %ld\n",
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	      0L, skel->bss->cons_pos);
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	CHECK(skel->bss->prod_pos != 3 * rec_sz,
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	      "err_prod_pos", "exp %ld, got %ld\n",
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	      3L * rec_sz, skel->bss->prod_pos);
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	/* poll for samples */
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	err = ring_buffer__poll(ringbuf, -1);
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	/* -EDONE is used as an indicator that we are done */
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	if (CHECK(err != -EDONE, "err_done", "done err: %d\n", err))
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		goto cleanup;
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	cnt = atomic_xchg(&sample_cnt, 0);
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	CHECK(cnt != 2, "cnt", "exp %d samples, got %d\n", 2, cnt);
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	/* we expect extra polling to return nothing */
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	err = ring_buffer__poll(ringbuf, 0);
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	if (CHECK(err != 0, "extra_samples", "poll result: %d\n", err))
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		goto cleanup;
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	cnt = atomic_xchg(&sample_cnt, 0);
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	CHECK(cnt != 0, "cnt", "exp %d samples, got %d\n", 0, cnt);
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	CHECK(skel->bss->dropped != 0, "err_dropped", "exp %ld, got %ld\n",
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	      0L, skel->bss->dropped);
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	CHECK(skel->bss->total != 2, "err_total", "exp %ld, got %ld\n",
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	      2L, skel->bss->total);
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	CHECK(skel->bss->discarded != 1, "err_discarded", "exp %ld, got %ld\n",
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	      1L, skel->bss->discarded);
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	/* now validate consumer position is updated and returned */
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	trigger_samples();
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	CHECK(skel->bss->cons_pos != 3 * rec_sz,
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	      "err_cons_pos", "exp %ld, got %ld\n",
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	      3L * rec_sz, skel->bss->cons_pos);
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	err = ring_buffer__poll(ringbuf, -1);
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	CHECK(err <= 0, "poll_err", "err %d\n", err);
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	cnt = atomic_xchg(&sample_cnt, 0);
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	CHECK(cnt != 2, "cnt", "exp %d samples, got %d\n", 2, cnt);
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	/* start poll in background w/ long timeout */
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	err = pthread_create(&thread, NULL, poll_thread, (void *)(long)10000);
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	if (CHECK(err, "bg_poll", "pthread_create failed: %d\n", err))
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		goto cleanup;
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	/* turn off notifications now */
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	skel->bss->flags = BPF_RB_NO_WAKEUP;
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	/* give background thread a bit of a time */
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	usleep(50000);
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	trigger_samples();
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	/* sleeping arbitrarily is bad, but no better way to know that
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	 * epoll_wait() **DID NOT** unblock in background thread
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	 */
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	usleep(50000);
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	/* background poll should still be blocked */
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	err = pthread_tryjoin_np(thread, (void **)&bg_ret);
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	if (CHECK(err != EBUSY, "try_join", "err %d\n", err))
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		goto cleanup;
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	/* BPF side did everything right */
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	CHECK(skel->bss->dropped != 0, "err_dropped", "exp %ld, got %ld\n",
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	      0L, skel->bss->dropped);
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	CHECK(skel->bss->total != 2, "err_total", "exp %ld, got %ld\n",
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	      2L, skel->bss->total);
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	CHECK(skel->bss->discarded != 1, "err_discarded", "exp %ld, got %ld\n",
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	      1L, skel->bss->discarded);
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	cnt = atomic_xchg(&sample_cnt, 0);
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	CHECK(cnt != 0, "cnt", "exp %d samples, got %d\n", 0, cnt);
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	/* clear flags to return to "adaptive" notification mode */
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	skel->bss->flags = 0;
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	/* produce new samples, no notification should be triggered, because
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	 * consumer is now behind
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	 */
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	trigger_samples();
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	/* background poll should still be blocked */
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	err = pthread_tryjoin_np(thread, (void **)&bg_ret);
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	if (CHECK(err != EBUSY, "try_join", "err %d\n", err))
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		goto cleanup;
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	/* still no samples, because consumer is behind */
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	cnt = atomic_xchg(&sample_cnt, 0);
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	CHECK(cnt != 0, "cnt", "exp %d samples, got %d\n", 0, cnt);
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	skel->bss->dropped = 0;
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	skel->bss->total = 0;
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	skel->bss->discarded = 0;
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	skel->bss->value = 333;
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	syscall(__NR_getpgid);
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	/* now force notifications */
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	skel->bss->flags = BPF_RB_FORCE_WAKEUP;
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	skel->bss->value = 777;
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	syscall(__NR_getpgid);
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	/* now we should get a pending notification */
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	usleep(50000);
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	err = pthread_tryjoin_np(thread, (void **)&bg_ret);
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	if (CHECK(err, "join_bg", "err %d\n", err))
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		goto cleanup;
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	if (CHECK(bg_ret <= 0, "bg_ret", "epoll_wait result: %ld", bg_ret))
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		goto cleanup;
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	/* due to timing variations, there could still be non-notified
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	 * samples, so consume them here to collect all the samples
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	 */
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	err = ring_buffer__consume(ringbuf);
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	CHECK(err < 0, "rb_consume", "failed: %d\b", err);
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	/* 3 rounds, 2 samples each */
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	cnt = atomic_xchg(&sample_cnt, 0);
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	CHECK(cnt != 6, "cnt", "exp %d samples, got %d\n", 6, cnt);
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	/* BPF side did everything right */
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	CHECK(skel->bss->dropped != 0, "err_dropped", "exp %ld, got %ld\n",
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	      0L, skel->bss->dropped);
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	CHECK(skel->bss->total != 2, "err_total", "exp %ld, got %ld\n",
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	      2L, skel->bss->total);
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	CHECK(skel->bss->discarded != 1, "err_discarded", "exp %ld, got %ld\n",
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	      1L, skel->bss->discarded);
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	test_ringbuf_lskel__detach(skel);
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cleanup:
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	ring_buffer__free(ringbuf);
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	test_ringbuf_lskel__destroy(skel);
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}
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