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 serial_test_perf_buffer(void)
  47 {
  48         int err, on_len, nr_on_cpus = 0, nr_cpus, i, j;
  49         int zero = 0, my_pid = getpid();
  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         err = bpf_map_update_elem(bpf_map__fd(skel->maps.my_pid_map), &zero, &my_pid, 0);
  75         if (!ASSERT_OK(err, "my_pid_update"))
  76                 goto out_close;
  77
  78         /* attach probe */
  79         err = test_perf_buffer__attach(skel);
  80         if (CHECK(err, "attach_kprobe", "err %d\n", err))
  81                 goto out_close;
  82
  83         /* set up perf buffer */
  84         pb = perf_buffer__new(bpf_map__fd(skel->maps.perf_buf_map), 1,
  85                               on_sample, NULL, &cpu_seen, NULL);
  86         if (!ASSERT_OK_PTR(pb, "perf_buf__new"))
  87                 goto out_close;
  88
  89         CHECK(perf_buffer__epoll_fd(pb) < 0, "epoll_fd",
  90               "bad fd: %d\n", perf_buffer__epoll_fd(pb));
  91
  92         /* trigger kprobe on every CPU */
  93         CPU_ZERO(&cpu_seen);
  94         for (i = 0; i < nr_cpus; i++) {
  95                 if (i >= on_len || !online[i]) {
  96                         printf("skipping offline CPU #%d\n", i);
  97                         continue;
  98                 }
  99
 100                 if (trigger_on_cpu(i))
 101                         goto out_close;
 102         }
 103
 104         /* read perf buffer */
 105         err = perf_buffer__poll(pb, 100);
 106         if (CHECK(err < 0, "perf_buffer__poll", "err %d\n", err))
 107                 goto out_free_pb;
 108
 109         if (CHECK(CPU_COUNT(&cpu_seen) != nr_on_cpus, "seen_cpu_cnt",
 110                   "expect %d, seen %d\n", nr_on_cpus, CPU_COUNT(&cpu_seen)))
 111                 goto out_free_pb;
 112
 113         if (CHECK(perf_buffer__buffer_cnt(pb) != nr_on_cpus, "buf_cnt",
 114                   "got %zu, expected %d\n", perf_buffer__buffer_cnt(pb), nr_on_cpus))
 115                 goto out_close;
 116
 117         for (i = 0, j = 0; i < nr_cpus; i++) {
 118                 if (i >= on_len || !online[i])
 119                         continue;
 120
 121                 fd = perf_buffer__buffer_fd(pb, j);
 122                 CHECK(fd < 0 || last_fd == fd, "fd_check", "last fd %d == fd %d\n", last_fd, fd);
 123                 last_fd = fd;
 124
 125                 err = perf_buffer__consume_buffer(pb, j);
 126                 if (CHECK(err, "drain_buf", "cpu %d, err %d\n", i, err))
 127                         goto out_close;
 128
 129                 CPU_CLR(i, &cpu_seen);
 130                 if (trigger_on_cpu(i))
 131                         goto out_close;
 132
 133                 err = perf_buffer__consume_buffer(pb, j);
 134                 if (CHECK(err, "consume_buf", "cpu %d, err %d\n", j, err))
 135                         goto out_close;
 136
 137                 if (CHECK(!CPU_ISSET(i, &cpu_seen), "cpu_seen", "cpu %d not seen\n", i))
 138                         goto out_close;
 139                 j++;
 140         }
 141
 142 out_free_pb:
 143         perf_buffer__free(pb);
 144 out_close:
 145         test_perf_buffer__destroy(skel);
 146         free(online);
 147 }