Commit 7aa424e0 authored by Feng Zhou's avatar Feng Zhou Committed by Andrii Nakryiko
Browse files

selftests/bpf: Fix some bugs in map_lookup_percpu_elem testcase 

comments from Andrii Nakryiko, details in here:
https://lore.kernel.org/lkml/20220511093854.411-1-zhoufeng.zf@bytedance.com/T/



use /* */ instead of //
use libbpf_num_possible_cpus() instead of sysconf(_SC_NPROCESSORS_ONLN)
use 8 bytes for value size
fix memory leak
use ASSERT_EQ instead of ASSERT_OK
add bpf_loop to fetch values on each possible CPU

Fixes: ed7c1377 ("selftests/bpf: add test case for bpf_map_lookup_percpu_elem")
Signed-off-by: default avatarFeng Zhou <zhoufeng.zf@bytedance.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Acked-by: default avatarYonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220518025053.20492-1-zhoufeng.zf@bytedance.com
parent 834650b5

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

+30 −18
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

// Copyright (c) 2022 Bytedance

/* Copyright (c) 2022 Bytedance */



#include <test_progs.h>



#include "test_map_lookup_percpu_elem.skel.h"



#define TEST_VALUE  1



void test_map_lookup_percpu_elem(void)

{

	struct test_map_lookup_percpu_elem *skel;

	int key = 0, ret;

	int nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);

	int *buf;

	__u64 key = 0, sum;

	int ret, i, nr_cpus = libbpf_num_possible_cpus();

	__u64 *buf;



	buf = (int *)malloc(nr_cpus*sizeof(int));

	buf = malloc(nr_cpus*sizeof(__u64));

	if (!ASSERT_OK_PTR(buf, "malloc"))

		return;

	memset(buf, 0, nr_cpus*sizeof(int));

	buf[0] = TEST_VALUE;



	skel = test_map_lookup_percpu_elem__open_and_load();

	if (!ASSERT_OK_PTR(skel, "test_map_lookup_percpu_elem__open_and_load"))

		return;

	for (i = 0; i < nr_cpus; i++)

		buf[i] = i;

	sum = (nr_cpus - 1) * nr_cpus / 2;



	skel = test_map_lookup_percpu_elem__open();

	if (!ASSERT_OK_PTR(skel, "test_map_lookup_percpu_elem__open"))

		goto exit;



	skel->rodata->my_pid = getpid();

	skel->rodata->nr_cpus = nr_cpus;



	ret = test_map_lookup_percpu_elem__load(skel);

	if (!ASSERT_OK(ret, "test_map_lookup_percpu_elem__load"))

		goto cleanup;



	ret = test_map_lookup_percpu_elem__attach(skel);

	ASSERT_OK(ret, "test_map_lookup_percpu_elem__attach");

	if (!ASSERT_OK(ret, "test_map_lookup_percpu_elem__attach"))

		goto cleanup;



	ret = bpf_map_update_elem(bpf_map__fd(skel->maps.percpu_array_map), &key, buf, 0);

	ASSERT_OK(ret, "percpu_array_map update");
@@ -37,10 +45,14 @@ void test_map_lookup_percpu_elem(void) 


	syscall(__NR_getuid);



	ret = skel->bss->percpu_array_elem_val == TEST_VALUE &&

	      skel->bss->percpu_hash_elem_val == TEST_VALUE &&

	      skel->bss->percpu_lru_hash_elem_val == TEST_VALUE;

	ASSERT_OK(!ret, "bpf_map_lookup_percpu_elem success");

	test_map_lookup_percpu_elem__detach(skel);



	ASSERT_EQ(skel->bss->percpu_array_elem_sum, sum, "percpu_array lookup percpu elem");

	ASSERT_EQ(skel->bss->percpu_hash_elem_sum, sum, "percpu_hash lookup percpu elem");

	ASSERT_EQ(skel->bss->percpu_lru_hash_elem_sum, sum, "percpu_lru_hash lookup percpu elem");



cleanup:

	test_map_lookup_percpu_elem__destroy(skel);

exit:

	free(buf);

}

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

+43 −21
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

// Copyright (c) 2022 Bytedance

/* Copyright (c) 2022 Bytedance */



#include "vmlinux.h"

#include <bpf/bpf_helpers.h>



int percpu_array_elem_val = 0;

int percpu_hash_elem_val = 0;

int percpu_lru_hash_elem_val = 0;

__u64 percpu_array_elem_sum = 0;

__u64 percpu_hash_elem_sum = 0;

__u64 percpu_lru_hash_elem_sum = 0;

const volatile int nr_cpus;

const volatile int my_pid;



struct {

	__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);

	__uint(max_entries, 1);

	__type(key, __u32);

	__type(value, __u32);

	__type(value, __u64);

} percpu_array_map SEC(".maps");



struct {

	__uint(type, BPF_MAP_TYPE_PERCPU_HASH);

	__uint(max_entries, 1);

	__type(key, __u32);

	__type(value, __u32);

	__type(key, __u64);

	__type(value, __u64);

} percpu_hash_map SEC(".maps");



struct {

	__uint(type, BPF_MAP_TYPE_LRU_PERCPU_HASH);

	__uint(max_entries, 1);

	__type(key, __u32);

	__type(value, __u32);

	__type(key, __u64);

	__type(value, __u64);

} percpu_lru_hash_map SEC(".maps");



struct read_percpu_elem_ctx {

	void *map;

	__u64 sum;

};



static int read_percpu_elem_callback(__u32 index, struct read_percpu_elem_ctx *ctx)

{

	__u64 key = 0;

	__u64 *value;



	value = bpf_map_lookup_percpu_elem(ctx->map, &key, index);

	if (value)

		ctx->sum += *value;

	return 0;

}



SEC("tp/syscalls/sys_enter_getuid")

int sysenter_getuid(const void *ctx)

{

	__u32 key = 0;

	__u32 cpu = 0;

	__u32 *value;

	struct read_percpu_elem_ctx map_ctx;



	value = bpf_map_lookup_percpu_elem(&percpu_array_map, &key, cpu);

	if (value)

		percpu_array_elem_val = *value;

	if (my_pid != (bpf_get_current_pid_tgid() >> 32))

		return 0;



	value = bpf_map_lookup_percpu_elem(&percpu_hash_map, &key, cpu);

	if (value)

		percpu_hash_elem_val = *value;

	map_ctx.map = &percpu_array_map;

	map_ctx.sum = 0;

	bpf_loop(nr_cpus, read_percpu_elem_callback, &map_ctx, 0);

	percpu_array_elem_sum = map_ctx.sum;



	value = bpf_map_lookup_percpu_elem(&percpu_lru_hash_map, &key, cpu);

	if (value)

		percpu_lru_hash_elem_val = *value;

	map_ctx.map = &percpu_hash_map;

	map_ctx.sum = 0;

	bpf_loop(nr_cpus, read_percpu_elem_callback, &map_ctx, 0);

	percpu_hash_elem_sum = map_ctx.sum;



	map_ctx.map = &percpu_lru_hash_map;

	map_ctx.sum = 0;

	bpf_loop(nr_cpus, read_percpu_elem_callback, &map_ctx, 0);

	percpu_lru_hash_elem_sum = map_ctx.sum;



	return 0;

}