From: Alexei Starovoitov <ast@xxxxxxxxxx>
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: Alexei Starovoitov <ast@xxxxxxxxxx>
---
.../testing/selftests/bpf/prog_tests/timer.c | 55 ++++
tools/testing/selftests/bpf/progs/timer.c | 297 ++++++++++++++++++
2 files changed, 352 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/timer.c
create mode 100644 tools/testing/selftests/bpf/progs/timer.c
diff --git a/tools/testing/selftests/bpf/prog_tests/timer.c b/tools/testing/selftests/bpf/prog_tests/timer.c
new file mode 100644
index 000000000000..25f40e1b9967
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/timer.c
@@ -0,0 +1,55 @@
+// 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);
+}
diff --git a/tools/testing/selftests/bpf/progs/timer.c b/tools/testing/selftests/bpf/progs/timer.c
new file mode 100644
index 000000000000..5f5309791649
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/timer.c
@@ -0,0 +1,297 @@
+// 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();
+}
--
2.30.2
