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

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <test_progs.h>
   3 #include "missed_kprobe.skel.h"
   4 #include "missed_kprobe_recursion.skel.h"
   5 #include "missed_tp_recursion.skel.h"
   6
   7 /*
   8  * Putting kprobe on bpf_fentry_test1 that calls bpf_kfunc_common_test
   9  * kfunc, which has also kprobe on. The latter won't get triggered due
  10  * to kprobe recursion check and kprobe missed counter is incremented.
  11  */
  12 static void test_missed_perf_kprobe(void)
  13 {
  14         LIBBPF_OPTS(bpf_test_run_opts, topts);
  15         struct bpf_link_info info = {};
  16         struct missed_kprobe *skel;
  17         __u32 len = sizeof(info);
  18         int err, prog_fd;
  19
  20         skel = missed_kprobe__open_and_load();
  21         if (!ASSERT_OK_PTR(skel, "missed_kprobe__open_and_load"))
  22                 goto cleanup;
  23
  24         err = missed_kprobe__attach(skel);
  25         if (!ASSERT_OK(err, "missed_kprobe__attach"))
  26                 goto cleanup;
  27
  28         prog_fd = bpf_program__fd(skel->progs.trigger);
  29         err = bpf_prog_test_run_opts(prog_fd, &topts);
  30         ASSERT_OK(err, "test_run");
  31         ASSERT_EQ(topts.retval, 0, "test_run");
  32
  33         err = bpf_link_get_info_by_fd(bpf_link__fd(skel->links.test2), &info, &len);
  34         if (!ASSERT_OK(err, "bpf_link_get_info_by_fd"))
  35                 goto cleanup;
  36
  37         ASSERT_EQ(info.type, BPF_LINK_TYPE_PERF_EVENT, "info.type");
  38         ASSERT_EQ(info.perf_event.type, BPF_PERF_EVENT_KPROBE, "info.perf_event.type");
  39         ASSERT_EQ(info.perf_event.kprobe.missed, 1, "info.perf_event.kprobe.missed");
  40
  41 cleanup:
  42         missed_kprobe__destroy(skel);
  43 }
  44
  45 static __u64 get_missed_count(int fd)
  46 {
  47         struct bpf_prog_info info = {};
  48         __u32 len = sizeof(info);
  49         int err;
  50
  51         err = bpf_prog_get_info_by_fd(fd, &info, &len);
  52         if (!ASSERT_OK(err, "bpf_prog_get_info_by_fd"))
  53                 return (__u64) -1;
  54         return info.recursion_misses;
  55 }
  56
  57 /*
  58  * Putting kprobe.multi on bpf_fentry_test1 that calls bpf_kfunc_common_test
  59  * kfunc which has 3 perf event kprobes and 1 kprobe.multi attached.
  60  *
  61  * Because fprobe (kprobe.multi attach layear) does not have strict recursion
  62  * check the kprobe's bpf_prog_active check is hit for test2-5.
  63  */
  64 static void test_missed_kprobe_recursion(void)
  65 {
  66         LIBBPF_OPTS(bpf_test_run_opts, topts);
  67         struct missed_kprobe_recursion *skel;
  68         int err, prog_fd;
  69
  70         skel = missed_kprobe_recursion__open_and_load();
  71         if (!ASSERT_OK_PTR(skel, "missed_kprobe_recursion__open_and_load"))
  72                 goto cleanup;
  73
  74         err = missed_kprobe_recursion__attach(skel);
  75         if (!ASSERT_OK(err, "missed_kprobe_recursion__attach"))
  76                 goto cleanup;
  77
  78         prog_fd = bpf_program__fd(skel->progs.trigger);
  79         err = bpf_prog_test_run_opts(prog_fd, &topts);
  80         ASSERT_OK(err, "test_run");
  81         ASSERT_EQ(topts.retval, 0, "test_run");
  82
  83         ASSERT_EQ(get_missed_count(bpf_program__fd(skel->progs.test1)), 0, "test1_recursion_misses");
  84         ASSERT_GE(get_missed_count(bpf_program__fd(skel->progs.test2)), 1, "test2_recursion_misses");
  85         ASSERT_GE(get_missed_count(bpf_program__fd(skel->progs.test3)), 1, "test3_recursion_misses");
  86         ASSERT_GE(get_missed_count(bpf_program__fd(skel->progs.test4)), 1, "test4_recursion_misses");
  87         ASSERT_GE(get_missed_count(bpf_program__fd(skel->progs.test5)), 1, "test5_recursion_misses");
  88
  89 cleanup:
  90         missed_kprobe_recursion__destroy(skel);
  91 }
  92
  93 /*
  94  * Putting kprobe on bpf_fentry_test1 that calls bpf_printk and invokes
  95  * bpf_trace_printk tracepoint. The bpf_trace_printk tracepoint has test[234]
  96  * programs attached to it.
  97  *
  98  * Because kprobe execution goes through bpf_prog_active check, programs
  99  * attached to the tracepoint will fail the recursion check and increment
 100  * the recursion_misses stats.
 101  */
 102 static void test_missed_tp_recursion(void)
 103 {
 104         LIBBPF_OPTS(bpf_test_run_opts, topts);
 105         struct missed_tp_recursion *skel;
 106         int err, prog_fd;
 107
 108         skel = missed_tp_recursion__open_and_load();
 109         if (!ASSERT_OK_PTR(skel, "missed_tp_recursion__open_and_load"))
 110                 goto cleanup;
 111
 112         err = missed_tp_recursion__attach(skel);
 113         if (!ASSERT_OK(err, "missed_tp_recursion__attach"))
 114                 goto cleanup;
 115
 116         prog_fd = bpf_program__fd(skel->progs.trigger);
 117         err = bpf_prog_test_run_opts(prog_fd, &topts);
 118         ASSERT_OK(err, "test_run");
 119         ASSERT_EQ(topts.retval, 0, "test_run");
 120
 121         ASSERT_EQ(get_missed_count(bpf_program__fd(skel->progs.test1)), 0, "test1_recursion_misses");
 122         ASSERT_EQ(get_missed_count(bpf_program__fd(skel->progs.test2)), 1, "test2_recursion_misses");
 123         ASSERT_EQ(get_missed_count(bpf_program__fd(skel->progs.test3)), 1, "test3_recursion_misses");
 124         ASSERT_EQ(get_missed_count(bpf_program__fd(skel->progs.test4)), 1, "test4_recursion_misses");
 125
 126 cleanup:
 127         missed_tp_recursion__destroy(skel);
 128 }
 129
 130 void test_missed(void)
 131 {
 132         if (test__start_subtest("perf_kprobe"))
 133                 test_missed_perf_kprobe();
 134         if (test__start_subtest("kprobe_recursion"))
 135                 test_missed_kprobe_recursion();
 136         if (test__start_subtest("tp_recursion"))
 137                 test_missed_tp_recursion();
 138 }