Commit 59e83c01 authored by Jiri Olsa's avatar Jiri Olsa Committed by Andrii Nakryiko
Browse files

selftests/bpf: Add test for recursion counts of perf event link kprobe 



Adding selftest that puts 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.

Disabling this test for arm64, because there's no fprobe support yet.

Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Tested-by: default avatarSong Liu <song@kernel.org>
Reviewed-by: default avatarSong Liu <song@kernel.org>
Acked-by: default avatarHou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/bpf/20230920213145.1941596-9-jolsa@kernel.org
parent 01e4ae47

tools/testing/selftests/bpf/DENYLIST.aarch64

+1 −0
Original line number Diff line number Diff line
@@ -10,3 +10,4 @@ fexit_test/fexit_many_args # fexit_many_args:FAIL:fexit_ma 
fill_link_info/kprobe_multi_link_info            # bpf_program__attach_kprobe_multi_opts unexpected error: -95

fill_link_info/kretprobe_multi_link_info         # bpf_program__attach_kprobe_multi_opts unexpected error: -95

fill_link_info/kprobe_multi_invalid_ubuff        # bpf_program__attach_kprobe_multi_opts unexpected error: -95

missed/kprobe_recursion                          # missed_kprobe_recursion__attach unexpected error: -95 (errno 95)

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

+51 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

#include <test_progs.h>

#include "missed_kprobe.skel.h"

#include "missed_kprobe_recursion.skel.h"



/*

 * Putting kprobe on bpf_fentry_test1 that calls bpf_kfunc_common_test
@@ -40,8 +41,58 @@ static void test_missed_perf_kprobe(void) 
	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_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");

	ASSERT_EQ(get_missed_count(bpf_program__fd(skel->progs.test5)), 1, "test5_recursion_misses");



cleanup:

	missed_kprobe_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();

}

tools/testing/selftests/bpf/progs/missed_kprobe_recursion.c

0 → 100644
+48 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

#include "vmlinux.h"

#include <bpf/bpf_helpers.h>

#include <bpf/bpf_tracing.h>

#include "../bpf_testmod/bpf_testmod_kfunc.h"



char _license[] SEC("license") = "GPL";



/*

 * No tests in here, just to trigger 'bpf_fentry_test*'

 * through tracing test_run

 */

SEC("fentry/bpf_modify_return_test")

int BPF_PROG(trigger)

{

	return 0;

}



SEC("kprobe.multi/bpf_fentry_test1")

int test1(struct pt_regs *ctx)

{

	bpf_kfunc_common_test();

	return 0;

}



SEC("kprobe/bpf_kfunc_common_test")

int test2(struct pt_regs *ctx)

{

	return 0;

}



SEC("kprobe/bpf_kfunc_common_test")

int test3(struct pt_regs *ctx)

{

	return 0;

}



SEC("kprobe/bpf_kfunc_common_test")

int test4(struct pt_regs *ctx)

{

	return 0;

}



SEC("kprobe.multi/bpf_kfunc_common_test")

int test5(struct pt_regs *ctx)

{

	return 0;

}