Commit 3540f7c6 authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by Daniel Borkmann

selftests/bpf: Add bpf_timer test.

Add bpf_timer test that creates timers in preallocated and
non-preallocated hash, in array and in lru maps.
Let array timer expire once and then re-arm it for 35 seconds.
Arm lru timer into the same callback.
Then arm and re-arm hash timers 10 times each.
At the last invocation of prealloc hash timer cancel the array timer.
Force timer free via LRU eviction and direct bpf_map_delete_elem.
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/20210715005417.78572-11-alexei.starovoitov@gmail.com
parent 7ddc80a4
// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2021 Facebook */
#include <test_progs.h>
#include "timer.skel.h"
static int timer(struct timer *timer_skel)
{
int err, prog_fd;
__u32 duration = 0, retval;
err = timer__attach(timer_skel);
if (!ASSERT_OK(err, "timer_attach"))
return err;
ASSERT_EQ(timer_skel->data->callback_check, 52, "callback_check1");
ASSERT_EQ(timer_skel->data->callback2_check, 52, "callback2_check1");
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__detach(timer_skel);
usleep(50); /* 10 usecs should be enough, but give it extra */
/* check that timer_cb1() was executed 10+10 times */
ASSERT_EQ(timer_skel->data->callback_check, 42, "callback_check2");
ASSERT_EQ(timer_skel->data->callback2_check, 42, "callback2_check2");
/* check that timer_cb2() was executed twice */
ASSERT_EQ(timer_skel->bss->bss_data, 10, "bss_data");
/* check that there were no errors in timer execution */
ASSERT_EQ(timer_skel->bss->err, 0, "err");
/* check that code paths completed */
ASSERT_EQ(timer_skel->bss->ok, 1 | 2 | 4, "ok");
return 0;
}
void test_timer(void)
{
struct timer *timer_skel = NULL;
int err;
timer_skel = timer__open_and_load();
if (!ASSERT_OK_PTR(timer_skel, "timer_skel_load"))
goto cleanup;
err = timer(timer_skel);
ASSERT_OK(err, "timer");
cleanup:
timer__destroy(timer_skel);
}
// 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 counter;
struct bpf_timer timer;
struct bpf_spin_lock lock; /* unused */
};
struct {
__uint(type, BPF_MAP_TYPE_HASH);
__uint(max_entries, 1000);
__type(key, int);
__type(value, struct hmap_elem);
} hmap SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_HASH);
__uint(map_flags, BPF_F_NO_PREALLOC);
__uint(max_entries, 1000);
__type(key, int);
__type(value, struct hmap_elem);
} hmap_malloc SEC(".maps");
struct elem {
struct bpf_timer t;
};
struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
__uint(max_entries, 2);
__type(key, int);
__type(value, struct elem);
} array SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_LRU_HASH);
__uint(max_entries, 4);
__type(key, int);
__type(value, struct elem);
} lru SEC(".maps");
__u64 bss_data;
__u64 err;
__u64 ok;
__u64 callback_check = 52;
__u64 callback2_check = 52;
#define ARRAY 1
#define HTAB 2
#define HTAB_MALLOC 3
#define LRU 4
/* callback for array and lru timers */
static int timer_cb1(void *map, int *key, struct bpf_timer *timer)
{
/* increment bss variable twice.
* Once via array timer callback and once via lru timer callback
*/
bss_data += 5;
/* *key == 0 - the callback was called for array timer.
* *key == 4 - the callback was called from lru timer.
*/
if (*key == ARRAY) {
struct bpf_timer *lru_timer;
int lru_key = LRU;
/* rearm array timer to be called again in ~35 seconds */
if (bpf_timer_start(timer, 1ull << 35, 0) != 0)
err |= 1;
lru_timer = bpf_map_lookup_elem(&lru, &lru_key);
if (!lru_timer)
return 0;
bpf_timer_set_callback(lru_timer, timer_cb1);
if (bpf_timer_start(lru_timer, 0, 0) != 0)
err |= 2;
} else if (*key == LRU) {
int lru_key, i;
for (i = LRU + 1;
i <= 100 /* for current LRU eviction algorithm this number
* should be larger than ~ lru->max_entries * 2
*/;
i++) {
struct elem init = {};
/* lru_key cannot be used as loop induction variable
* otherwise the loop will be unbounded.
*/
lru_key = i;
/* add more elements into lru map to push out current
* element and force deletion of this timer
*/
bpf_map_update_elem(map, &lru_key, &init, 0);
/* look it up to bump it into active list */
bpf_map_lookup_elem(map, &lru_key);
/* keep adding until *key changes underneath,
* which means that key/timer memory was reused
*/
if (*key != LRU)
break;
}
/* check that the timer was removed */
if (bpf_timer_cancel(timer) != -EINVAL)
err |= 4;
ok |= 1;
}
return 0;
}
SEC("fentry/bpf_fentry_test1")
int BPF_PROG(test1, int a)
{
struct bpf_timer *arr_timer, *lru_timer;
struct elem init = {};
int lru_key = LRU;
int array_key = ARRAY;
arr_timer = bpf_map_lookup_elem(&array, &array_key);
if (!arr_timer)
return 0;
bpf_timer_init(arr_timer, &array, CLOCK_MONOTONIC);
bpf_map_update_elem(&lru, &lru_key, &init, 0);
lru_timer = bpf_map_lookup_elem(&lru, &lru_key);
if (!lru_timer)
return 0;
bpf_timer_init(lru_timer, &lru, CLOCK_MONOTONIC);
bpf_timer_set_callback(arr_timer, timer_cb1);
bpf_timer_start(arr_timer, 0 /* call timer_cb1 asap */, 0);
/* init more timers to check that array destruction
* doesn't leak timer memory.
*/
array_key = 0;
arr_timer = bpf_map_lookup_elem(&array, &array_key);
if (!arr_timer)
return 0;
bpf_timer_init(arr_timer, &array, CLOCK_MONOTONIC);
return 0;
}
/* callback for prealloc and non-prealloca hashtab timers */
static int timer_cb2(void *map, int *key, struct hmap_elem *val)
{
if (*key == HTAB)
callback_check--;
else
callback2_check--;
if (val->counter > 0 && --val->counter) {
/* re-arm the timer again to execute after 1 usec */
bpf_timer_start(&val->timer, 1000, 0);
} else if (*key == HTAB) {
struct bpf_timer *arr_timer;
int array_key = ARRAY;
/* cancel arr_timer otherwise bpf_fentry_test1 prog
* will stay alive forever.
*/
arr_timer = bpf_map_lookup_elem(&array, &array_key);
if (!arr_timer)
return 0;
if (bpf_timer_cancel(arr_timer) != 1)
/* bpf_timer_cancel should return 1 to indicate
* that arr_timer was active at this time
*/
err |= 8;
/* try to cancel ourself. It shouldn't deadlock. */
if (bpf_timer_cancel(&val->timer) != -EDEADLK)
err |= 16;
/* delete this key and this timer anyway.
* It shouldn't deadlock either.
*/
bpf_map_delete_elem(map, key);
/* in preallocated hashmap both 'key' and 'val' could have been
* reused to store another map element (like in LRU above),
* but in controlled test environment the below test works.
* It's not a use-after-free. The memory is owned by the map.
*/
if (bpf_timer_start(&val->timer, 1000, 0) != -EINVAL)
err |= 32;
ok |= 2;
} else {
if (*key != HTAB_MALLOC)
err |= 64;
/* try to cancel ourself. It shouldn't deadlock. */
if (bpf_timer_cancel(&val->timer) != -EDEADLK)
err |= 128;
/* delete this key and this timer anyway.
* It shouldn't deadlock either.
*/
bpf_map_delete_elem(map, key);
/* in non-preallocated hashmap both 'key' and 'val' are RCU
* protected and still valid though this element was deleted
* from the map. Arm this timer for ~35 seconds. When callback
* finishes the call_rcu will invoke:
* htab_elem_free_rcu
* check_and_free_timer
* bpf_timer_cancel_and_free
* to cancel this 35 second sleep and delete the timer for real.
*/
if (bpf_timer_start(&val->timer, 1ull << 35, 0) != 0)
err |= 256;
ok |= 4;
}
return 0;
}
int bpf_timer_test(void)
{
struct hmap_elem *val;
int key = HTAB, key_malloc = HTAB_MALLOC;
val = bpf_map_lookup_elem(&hmap, &key);
if (val) {
if (bpf_timer_init(&val->timer, &hmap, CLOCK_BOOTTIME) != 0)
err |= 512;
bpf_timer_set_callback(&val->timer, timer_cb2);
bpf_timer_start(&val->timer, 1000, 0);
}
val = bpf_map_lookup_elem(&hmap_malloc, &key_malloc);
if (val) {
if (bpf_timer_init(&val->timer, &hmap_malloc, CLOCK_BOOTTIME) != 0)
err |= 1024;
bpf_timer_set_callback(&val->timer, timer_cb2);
bpf_timer_start(&val->timer, 1000, 0);
}
return 0;
}
SEC("fentry/bpf_fentry_test2")
int BPF_PROG(test2, int a, int b)
{
struct hmap_elem init = {}, *val;
int key = HTAB, key_malloc = HTAB_MALLOC;
init.counter = 10; /* number of times to trigger timer_cb2 */
bpf_map_update_elem(&hmap, &key, &init, 0);
val = bpf_map_lookup_elem(&hmap, &key);
if (val)
bpf_timer_init(&val->timer, &hmap, CLOCK_BOOTTIME);
/* update the same key to free the timer */
bpf_map_update_elem(&hmap, &key, &init, 0);
bpf_map_update_elem(&hmap_malloc, &key_malloc, &init, 0);
val = bpf_map_lookup_elem(&hmap_malloc, &key_malloc);
if (val)
bpf_timer_init(&val->timer, &hmap_malloc, CLOCK_BOOTTIME);
/* update the same key to free the timer */
bpf_map_update_elem(&hmap_malloc, &key_malloc, &init, 0);
/* init more timers to check that htab operations
* don't leak timer memory.
*/
key = 0;
bpf_map_update_elem(&hmap, &key, &init, 0);
val = bpf_map_lookup_elem(&hmap, &key);
if (val)
bpf_timer_init(&val->timer, &hmap, CLOCK_BOOTTIME);
bpf_map_delete_elem(&hmap, &key);
bpf_map_update_elem(&hmap, &key, &init, 0);
val = bpf_map_lookup_elem(&hmap, &key);
if (val)
bpf_timer_init(&val->timer, &hmap, CLOCK_BOOTTIME);
/* and with non-prealloc htab */
key_malloc = 0;
bpf_map_update_elem(&hmap_malloc, &key_malloc, &init, 0);
val = bpf_map_lookup_elem(&hmap_malloc, &key_malloc);
if (val)
bpf_timer_init(&val->timer, &hmap_malloc, CLOCK_BOOTTIME);
bpf_map_delete_elem(&hmap_malloc, &key_malloc);
bpf_map_update_elem(&hmap_malloc, &key_malloc, &init, 0);
val = bpf_map_lookup_elem(&hmap_malloc, &key_malloc);
if (val)
bpf_timer_init(&val->timer, &hmap_malloc, CLOCK_BOOTTIME);
return bpf_timer_test();
}
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