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 */
 12static 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
 41cleanup:
 42	missed_kprobe__destroy(skel);
 43}
 44
 45static __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 */
 64static 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	ASSERT_EQ(get_missed_count(bpf_program__fd(skel->progs.test6)), 1, "test6_recursion_misses");
 89
 90cleanup:
 91	missed_kprobe_recursion__destroy(skel);
 92}
 93
 94/*
 95 * Putting kprobe on bpf_fentry_test1 that calls bpf_printk and invokes
 96 * bpf_trace_printk tracepoint. The bpf_trace_printk tracepoint has test[234]
 97 * programs attached to it.
 98 *
 99 * Because kprobe execution goes through bpf_prog_active check, programs
100 * attached to the tracepoint will fail the recursion check and increment
101 * the recursion_misses stats.
102 */
103static void test_missed_tp_recursion(void)
104{
105	LIBBPF_OPTS(bpf_test_run_opts, topts);
106	struct missed_tp_recursion *skel;
107	int err, prog_fd;
108
109	skel = missed_tp_recursion__open_and_load();
110	if (!ASSERT_OK_PTR(skel, "missed_tp_recursion__open_and_load"))
111		goto cleanup;
112
113	err = missed_tp_recursion__attach(skel);
114	if (!ASSERT_OK(err, "missed_tp_recursion__attach"))
115		goto cleanup;
116
117	prog_fd = bpf_program__fd(skel->progs.trigger);
118	err = bpf_prog_test_run_opts(prog_fd, &topts);
119	ASSERT_OK(err, "test_run");
120	ASSERT_EQ(topts.retval, 0, "test_run");
121
122	ASSERT_EQ(get_missed_count(bpf_program__fd(skel->progs.test1)), 0, "test1_recursion_misses");
123	ASSERT_EQ(get_missed_count(bpf_program__fd(skel->progs.test2)), 1, "test2_recursion_misses");
124	ASSERT_EQ(get_missed_count(bpf_program__fd(skel->progs.test3)), 1, "test3_recursion_misses");
125	ASSERT_EQ(get_missed_count(bpf_program__fd(skel->progs.test4)), 1, "test4_recursion_misses");
126
127cleanup:
128	missed_tp_recursion__destroy(skel);
129}
130
131void test_missed(void)
132{
133	if (test__start_subtest("perf_kprobe"))
134		test_missed_perf_kprobe();
135	if (test__start_subtest("kprobe_recursion"))
136		test_missed_kprobe_recursion();
137	if (test__start_subtest("tp_recursion"))
138		test_missed_tp_recursion();
139}