tools/testing/selftests/bpf/prog_tests/perf_buffer.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #define _GNU_SOURCE
   3 #include <pthread.h>
   4 #include <sched.h>
   5 #include <sys/socket.h>
   6 #include <test_progs.h>
   7 #include "test_perf_buffer.skel.h"
   8 #include "bpf/libbpf_internal.h"
   9
  10 static int duration;
  11
  12 /* AddressSanitizer sometimes crashes due to data dereference below, due to
  13  * this being mmap()'ed memory. Disable instrumentation with
  14  * no_sanitize_address attribute
  15  */
  16 __attribute__((no_sanitize_address))
  17 static void on_sample(void *ctx, int cpu, void *data, __u32 size)
  18 {
  19         int cpu_data = *(int *)data, duration = 0;
  20         cpu_set_t *cpu_seen = ctx;
  21
  22         if (cpu_data != cpu)
  23                 CHECK(cpu_data != cpu, "check_cpu_data",
  24                       "cpu_data %d != cpu %d\n", cpu_data, cpu);
  25
  26         CPU_SET(cpu, cpu_seen);
  27 }
  28
  29 int trigger_on_cpu(int cpu)
  30 {
  31         cpu_set_t cpu_set;
  32         int err;
  33
  34         CPU_ZERO(&cpu_set);
  35         CPU_SET(cpu, &cpu_set);
  36
  37         err = pthread_setaffinity_np(pthread_self(), sizeof(cpu_set), &cpu_set);
  38         if (err && CHECK(err, "set_affinity", "cpu #%d, err %d\n", cpu, err))
  39                 return err;
  40
  41         usleep(1);
  42
  43         return 0;
  44 }
  45
  46 void test_perf_buffer(void)
  47 {
  48         int err, on_len, nr_on_cpus = 0, nr_cpus, i;
  49         struct perf_buffer_opts pb_opts = {};
  50         struct test_perf_buffer *skel;
  51         cpu_set_t cpu_seen;
  52         struct perf_buffer *pb;
  53         int last_fd = -1, fd;
  54         bool *online;
  55
  56         nr_cpus = libbpf_num_possible_cpus();
  57         if (CHECK(nr_cpus < 0, "nr_cpus", "err %d\n", nr_cpus))
  58                 return;
  59
  60         err = parse_cpu_mask_file("/sys/devices/system/cpu/online",
  61                                   &online, &on_len);
  62         if (CHECK(err, "nr_on_cpus", "err %d\n", err))
  63                 return;
  64
  65         for (i = 0; i < on_len; i++)
  66                 if (online[i])
  67                         nr_on_cpus++;
  68
  69         /* load program */
  70         skel = test_perf_buffer__open_and_load();
  71         if (CHECK(!skel, "skel_load", "skeleton open/load failed\n"))
  72                 goto out_close;
  73
  74         /* attach probe */
  75         err = test_perf_buffer__attach(skel);
  76         if (CHECK(err, "attach_kprobe", "err %d\n", err))
  77                 goto out_close;
  78
  79         /* set up perf buffer */
  80         pb_opts.sample_cb = on_sample;
  81         pb_opts.ctx = &cpu_seen;
  82         pb = perf_buffer__new(bpf_map__fd(skel->maps.perf_buf_map), 1, &pb_opts);
  83         if (CHECK(IS_ERR(pb), "perf_buf__new", "err %ld\n", PTR_ERR(pb)))
  84                 goto out_close;
  85
  86         CHECK(perf_buffer__epoll_fd(pb) < 0, "epoll_fd",
  87               "bad fd: %d\n", perf_buffer__epoll_fd(pb));
  88
  89         /* trigger kprobe on every CPU */
  90         CPU_ZERO(&cpu_seen);
  91         for (i = 0; i < nr_cpus; i++) {
  92                 if (i >= on_len || !online[i]) {
  93                         printf("skipping offline CPU #%d\n", i);
  94                         continue;
  95                 }
  96
  97                 if (trigger_on_cpu(i))
  98                         goto out_close;
  99         }
 100
 101         /* read perf buffer */
 102         err = perf_buffer__poll(pb, 100);
 103         if (CHECK(err < 0, "perf_buffer__poll", "err %d\n", err))
 104                 goto out_free_pb;
 105
 106         if (CHECK(CPU_COUNT(&cpu_seen) != nr_on_cpus, "seen_cpu_cnt",
 107                   "expect %d, seen %d\n", nr_on_cpus, CPU_COUNT(&cpu_seen)))
 108                 goto out_free_pb;
 109
 110         if (CHECK(perf_buffer__buffer_cnt(pb) != nr_cpus, "buf_cnt",
 111                   "got %zu, expected %d\n", perf_buffer__buffer_cnt(pb), nr_cpus))
 112                 goto out_close;
 113
 114         for (i = 0; i < nr_cpus; i++) {
 115                 if (i >= on_len || !online[i])
 116                         continue;
 117
 118                 fd = perf_buffer__buffer_fd(pb, i);
 119                 CHECK(fd < 0 || last_fd == fd, "fd_check", "last fd %d == fd %d\n", last_fd, fd);
 120                 last_fd = fd;
 121
 122                 err = perf_buffer__consume_buffer(pb, i);
 123                 if (CHECK(err, "drain_buf", "cpu %d, err %d\n", i, err))
 124                         goto out_close;
 125
 126                 CPU_CLR(i, &cpu_seen);
 127                 if (trigger_on_cpu(i))
 128                         goto out_close;
 129
 130                 err = perf_buffer__consume_buffer(pb, i);
 131                 if (CHECK(err, "consume_buf", "cpu %d, err %d\n", i, err))
 132                         goto out_close;
 133
 134                 if (CHECK(!CPU_ISSET(i, &cpu_seen), "cpu_seen", "cpu %d not seen\n", i))
 135                         goto out_close;
 136         }
 137
 138 out_free_pb:
 139         perf_buffer__free(pb);
 140 out_close:
 141         test_perf_buffer__destroy(skel);
 142         free(online);
 143 }