Quelle  missed.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0
#include <test_progs.h>
#include "missed_kprobe.skel.h"
#include "missed_kprobe_recursion.skel.h"
#include "missed_tp_recursion.skel.h"

/*
 * Putting kprobe on bpf_fentry_test1 that calls bpf_kfunc_common_test
 * kfunc, which has also kprobe on. The latter won't get triggered due
 * to kprobe recursion check and kprobe missed counter is incremented.
 */
static void test_missed_perf_kprobe(void)
{
 LIBBPF_OPTS(bpf_test_run_opts, topts);
 struct bpf_link_info info = {};
 struct missed_kprobe *skel;
 __u32 len = sizeof(info);
 int err, prog_fd;

 skel = missed_kprobe__open_and_load();
 if (!ASSERT_OK_PTR(skel, "missed_kprobe__open_and_load"))
  goto cleanup;

 err = missed_kprobe__attach(skel);
 if (!ASSERT_OK(err, "missed_kprobe__attach"))
  goto cleanup;

 prog_fd = bpf_program__fd(skel->progs.trigger);
 err = bpf_prog_test_run_opts(prog_fd, &topts);
 ASSERT_OK(err, "test_run");
 ASSERT_EQ(topts.retval, 0, "test_run");

 err = bpf_link_get_info_by_fd(bpf_link__fd(skel->links.test2), &info, &len);
 if (!ASSERT_OK(err, "bpf_link_get_info_by_fd"))
  goto cleanup;

 ASSERT_EQ(info.type, BPF_LINK_TYPE_PERF_EVENT, "info.type");
 ASSERT_EQ(info.perf_event.type, BPF_PERF_EVENT_KPROBE, "info.perf_event.type");
 ASSERT_EQ(info.perf_event.kprobe.missed, 1, "info.perf_event.kprobe.missed");

cleanup:
 missed_kprobe__destroy(skel);
}

static __u64 get_missed_count(int fd)
{
 struct bpf_prog_info info = {};
 __u32 len = sizeof(info);
 int err;

 err = bpf_prog_get_info_by_fd(fd, &info, &len);
 if (!ASSERT_OK(err, "bpf_prog_get_info_by_fd"))
  return (__u64) -1;
 return info.recursion_misses;
}

/*
 * Putting kprobe.multi on bpf_fentry_test1 that calls bpf_kfunc_common_test
 * kfunc which has 3 perf event kprobes and 1 kprobe.multi attached.
 *
 * Because fprobe (kprobe.multi attach layear) does not have strict recursion
 * check the kprobe's bpf_prog_active check is hit for test2-5.
 */
static void test_missed_kprobe_recursion(void)
{
 LIBBPF_OPTS(bpf_test_run_opts, topts);
 struct missed_kprobe_recursion *skel;
 int err, prog_fd;

 skel = missed_kprobe_recursion__open_and_load();
 if (!ASSERT_OK_PTR(skel, "missed_kprobe_recursion__open_and_load"))
  goto cleanup;

 err = missed_kprobe_recursion__attach(skel);
 if (!ASSERT_OK(err, "missed_kprobe_recursion__attach"))
  goto cleanup;

 prog_fd = bpf_program__fd(skel->progs.trigger);
 err = bpf_prog_test_run_opts(prog_fd, &topts);
 ASSERT_OK(err, "test_run");
 ASSERT_EQ(topts.retval, 0, "test_run");

 ASSERT_EQ(get_missed_count(bpf_program__fd(skel->progs.test1)), 0, "test1_recursion_misses");
 ASSERT_GE(get_missed_count(bpf_program__fd(skel->progs.test2)), 1, "test2_recursion_misses");
 ASSERT_GE(get_missed_count(bpf_program__fd(skel->progs.test3)), 1, "test3_recursion_misses");
 ASSERT_GE(get_missed_count(bpf_program__fd(skel->progs.test4)), 1, "test4_recursion_misses");
 ASSERT_GE(get_missed_count(bpf_program__fd(skel->progs.test5)), 1, "test5_recursion_misses");
 ASSERT_EQ(get_missed_count(bpf_program__fd(skel->progs.test6)), 1, "test6_recursion_misses");

cleanup:
 missed_kprobe_recursion__destroy(skel);
}

/*
 * Putting kprobe on bpf_fentry_test1 that calls bpf_printk and invokes
 * bpf_trace_printk tracepoint. The bpf_trace_printk tracepoint has test[234]
 * programs attached to it.
 *
 * Because kprobe execution goes through bpf_prog_active check, programs
 * attached to the tracepoint will fail the recursion check and increment
 * the recursion_misses stats.
 */
static void test_missed_tp_recursion(void)
{
 LIBBPF_OPTS(bpf_test_run_opts, topts);
 struct missed_tp_recursion *skel;
 int err, prog_fd;

 skel = missed_tp_recursion__open_and_load();
 if (!ASSERT_OK_PTR(skel, "missed_tp_recursion__open_and_load"))
  goto cleanup;

 err = missed_tp_recursion__attach(skel);
 if (!ASSERT_OK(err, "missed_tp_recursion__attach"))
  goto cleanup;

 prog_fd = bpf_program__fd(skel->progs.trigger);
 err = bpf_prog_test_run_opts(prog_fd, &topts);
 ASSERT_OK(err, "test_run");
 ASSERT_EQ(topts.retval, 0, "test_run");

 ASSERT_EQ(get_missed_count(bpf_program__fd(skel->progs.test1)), 0, "test1_recursion_misses");
 ASSERT_EQ(get_missed_count(bpf_program__fd(skel->progs.test2)), 1, "test2_recursion_misses");
 ASSERT_EQ(get_missed_count(bpf_program__fd(skel->progs.test3)), 1, "test3_recursion_misses");
 ASSERT_EQ(get_missed_count(bpf_program__fd(skel->progs.test4)), 1, "test4_recursion_misses");

cleanup:
 missed_tp_recursion__destroy(skel);
}

void test_missed(void)
{
 if (test__start_subtest("perf_kprobe"))
  test_missed_perf_kprobe();
 if (test__start_subtest("kprobe_recursion"))
  test_missed_kprobe_recursion();
 if (test__start_subtest("tp_recursion"))
  test_missed_tp_recursion();
}