Commit 61f71e74 authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by Daniel Borkmann
Browse files

selftests/bpf: Add a test with bpf_timer in inner map. 



Check that map-in-map supports bpf timers.

Check that indirect "recursion" of timer callbacks works:
timer_cb1() { bpf_timer_set_callback(timer_cb2); }
timer_cb2() { bpf_timer_set_callback(timer_cb1); }

Check that
  bpf_map_release
    htab_free_prealloced_timers
      bpf_timer_cancel_and_free
        hrtimer_cancel
works while timer cb is running.
"while true; do ./test_progs -t timer_mim; done"
is a great stress test. It caught missing timer cancel in htab->extra_elems.

timer_mim_reject.c is a negative test that checks
that timer<->map mismatch is prevented.

Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Acked-by: default avatarToke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20210715005417.78572-12-alexei.starovoitov@gmail.com
parent 3540f7c6

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

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// SPDX-License-Identifier: GPL-2.0

/* Copyright (c) 2021 Facebook */

#include <test_progs.h>

#include "timer_mim.skel.h"

#include "timer_mim_reject.skel.h"



static int timer_mim(struct timer_mim *timer_skel)

{

	__u32 duration = 0, retval;

	__u64 cnt1, cnt2;

	int err, prog_fd, key1 = 1;



	err = timer_mim__attach(timer_skel);

	if (!ASSERT_OK(err, "timer_attach"))

		return err;



	prog_fd = bpf_program__fd(timer_skel->progs.test1);

	err = bpf_prog_test_run(prog_fd, 1, NULL, 0,

				NULL, NULL, &retval, &duration);

	ASSERT_OK(err, "test_run");

	ASSERT_EQ(retval, 0, "test_run");

	timer_mim__detach(timer_skel);



	/* check that timer_cb[12] are incrementing 'cnt' */

	cnt1 = READ_ONCE(timer_skel->bss->cnt);

	usleep(200); /* 100 times more than interval */

	cnt2 = READ_ONCE(timer_skel->bss->cnt);

	ASSERT_GT(cnt2, cnt1, "cnt");



	ASSERT_EQ(timer_skel->bss->err, 0, "err");

	/* check that code paths completed */

	ASSERT_EQ(timer_skel->bss->ok, 1 | 2, "ok");



	close(bpf_map__fd(timer_skel->maps.inner_htab));

	err = bpf_map_delete_elem(bpf_map__fd(timer_skel->maps.outer_arr), &key1);

	ASSERT_EQ(err, 0, "delete inner map");



	/* check that timer_cb[12] are no longer running */

	cnt1 = READ_ONCE(timer_skel->bss->cnt);

	usleep(200);

	cnt2 = READ_ONCE(timer_skel->bss->cnt);

	ASSERT_EQ(cnt2, cnt1, "cnt");



	return 0;

}



void test_timer_mim(void)

{

	struct timer_mim_reject *timer_reject_skel = NULL;

	libbpf_print_fn_t old_print_fn = NULL;

	struct timer_mim *timer_skel = NULL;

	int err;



	old_print_fn = libbpf_set_print(NULL);

	timer_reject_skel = timer_mim_reject__open_and_load();

	libbpf_set_print(old_print_fn);

	if (!ASSERT_ERR_PTR(timer_reject_skel, "timer_reject_skel_load"))

		goto cleanup;



	timer_skel = timer_mim__open_and_load();

	if (!ASSERT_OK_PTR(timer_skel, "timer_skel_load"))

		goto cleanup;



	err = timer_mim(timer_skel);

	ASSERT_OK(err, "timer_mim");

cleanup:

	timer_mim__destroy(timer_skel);

	timer_mim_reject__destroy(timer_reject_skel);

}

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

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// SPDX-License-Identifier: GPL-2.0

/* Copyright (c) 2021 Facebook */

#include <linux/bpf.h>

#include <time.h>

#include <errno.h>

#include <bpf/bpf_helpers.h>

#include "bpf_tcp_helpers.h"



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

struct hmap_elem {

	int pad; /* unused */

	struct bpf_timer timer;

};



struct inner_map {

	__uint(type, BPF_MAP_TYPE_HASH);

	__uint(max_entries, 1024);

	__type(key, int);

	__type(value, struct hmap_elem);

} inner_htab SEC(".maps");



#define ARRAY_KEY 1

#define HASH_KEY 1234



struct outer_arr {

	__uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);

	__uint(max_entries, 2);

	__uint(key_size, sizeof(int));

	__uint(value_size, sizeof(int));

	__array(values, struct inner_map);

} outer_arr SEC(".maps") = {

	.values = { [ARRAY_KEY] = &inner_htab },

};



__u64 err;

__u64 ok;

__u64 cnt;



static int timer_cb1(void *map, int *key, struct hmap_elem *val);



static int timer_cb2(void *map, int *key, struct hmap_elem *val)

{

	cnt++;

	bpf_timer_set_callback(&val->timer, timer_cb1);

	if (bpf_timer_start(&val->timer, 1000, 0))

		err |= 1;

	ok |= 1;

	return 0;

}



/* callback for inner hash map */

static int timer_cb1(void *map, int *key, struct hmap_elem *val)

{

	cnt++;

	bpf_timer_set_callback(&val->timer, timer_cb2);

	if (bpf_timer_start(&val->timer, 1000, 0))

		err |= 2;

	/* Do a lookup to make sure 'map' and 'key' pointers are correct */

	bpf_map_lookup_elem(map, key);

	ok |= 2;

	return 0;

}



SEC("fentry/bpf_fentry_test1")

int BPF_PROG(test1, int a)

{

	struct hmap_elem init = {};

	struct bpf_map *inner_map;

	struct hmap_elem *val;

	int array_key = ARRAY_KEY;

	int hash_key = HASH_KEY;



	inner_map = bpf_map_lookup_elem(&outer_arr, &array_key);

	if (!inner_map)

		return 0;



	bpf_map_update_elem(inner_map, &hash_key, &init, 0);

	val = bpf_map_lookup_elem(inner_map, &hash_key);

	if (!val)

		return 0;



	bpf_timer_init(&val->timer, inner_map, CLOCK_MONOTONIC);

	if (bpf_timer_set_callback(&val->timer, timer_cb1))

		err |= 4;

	if (bpf_timer_start(&val->timer, 0, 0))

		err |= 8;

	return 0;

}

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

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// SPDX-License-Identifier: GPL-2.0

/* Copyright (c) 2021 Facebook */

#include <linux/bpf.h>

#include <time.h>

#include <errno.h>

#include <bpf/bpf_helpers.h>

#include "bpf_tcp_helpers.h"



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

struct hmap_elem {

	int pad; /* unused */

	struct bpf_timer timer;

};



struct inner_map {

	__uint(type, BPF_MAP_TYPE_HASH);

	__uint(max_entries, 1024);

	__type(key, int);

	__type(value, struct hmap_elem);

} inner_htab SEC(".maps");



#define ARRAY_KEY 1

#define ARRAY_KEY2 2

#define HASH_KEY 1234



struct outer_arr {

	__uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);

	__uint(max_entries, 2);

	__uint(key_size, sizeof(int));

	__uint(value_size, sizeof(int));

	__array(values, struct inner_map);

} outer_arr SEC(".maps") = {

	.values = { [ARRAY_KEY] = &inner_htab },

};



__u64 err;

__u64 ok;

__u64 cnt;



/* callback for inner hash map */

static int timer_cb(void *map, int *key, struct hmap_elem *val)

{

	return 0;

}



SEC("fentry/bpf_fentry_test1")

int BPF_PROG(test1, int a)

{

	struct hmap_elem init = {};

	struct bpf_map *inner_map, *inner_map2;

	struct hmap_elem *val;

	int array_key = ARRAY_KEY;

	int array_key2 = ARRAY_KEY2;

	int hash_key = HASH_KEY;



	inner_map = bpf_map_lookup_elem(&outer_arr, &array_key);

	if (!inner_map)

		return 0;



	inner_map2 = bpf_map_lookup_elem(&outer_arr, &array_key2);

	if (!inner_map2)

		return 0;

	bpf_map_update_elem(inner_map, &hash_key, &init, 0);

	val = bpf_map_lookup_elem(inner_map, &hash_key);

	if (!val)

		return 0;



	bpf_timer_init(&val->timer, inner_map2, CLOCK_MONOTONIC);

	if (bpf_timer_set_callback(&val->timer, timer_cb))

		err |= 4;

	if (bpf_timer_start(&val->timer, 0, 0))

		err |= 8;

	return 0;

}