On Thu, Jan 8, 2026 at 2:56 PM Samuel Wu <[email protected]> wrote:
>
> Sets up the framework to test wakeup_sources iterators using BPF, and
> adds a few basic tests.
>
> Adds several helper functions that for grabbing and releasing a
> wakelock, abstracting out key functions to setup a framework for testing
> wakeup_sources.
>
> Additionally, adds 3 tests:
> 1. check_active_count: Checks that stats related to active_count are
> properly set after several lock/unlock cycles
> 2. check_sleep_times: Checks that time accounting related to sleep are
> properly calculated
> 3. check_no_infinite_reads: Checks that the iterator traversal returns
> NULL at the end
>
> Signed-off-by: Samuel Wu <[email protected]>
> ---
> tools/testing/selftests/bpf/config | 1 +
> .../bpf/prog_tests/wakeup_source_iter.c | 281 ++++++++++++++++++
> .../selftests/bpf/progs/wakeup_source_iter.c | 70 +++++
> 3 files changed, 352 insertions(+)
> create mode 100644
> tools/testing/selftests/bpf/prog_tests/wakeup_source_iter.c
> create mode 100644 tools/testing/selftests/bpf/progs/wakeup_source_iter.c
>
> diff --git a/tools/testing/selftests/bpf/config
> b/tools/testing/selftests/bpf/config
> index 558839e3c185..c12c5e04b81f 100644
> --- a/tools/testing/selftests/bpf/config
> +++ b/tools/testing/selftests/bpf/config
> @@ -111,6 +111,7 @@ CONFIG_IP6_NF_IPTABLES=y
> CONFIG_IP6_NF_FILTER=y
> CONFIG_NF_NAT=y
> CONFIG_PACKET=y
> +CONFIG_PM_WAKELOCKS=y
> CONFIG_RC_CORE=y
> CONFIG_SAMPLES=y
> CONFIG_SAMPLE_LIVEPATCH=m
> diff --git a/tools/testing/selftests/bpf/prog_tests/wakeup_source_iter.c
> b/tools/testing/selftests/bpf/prog_tests/wakeup_source_iter.c
> new file mode 100644
> index 000000000000..31729f11585e
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/prog_tests/wakeup_source_iter.c
> @@ -0,0 +1,281 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright (c) 2026 Google LLC */
> +
> +#include <test_progs.h>
> +#include <bpf/libbpf.h>
> +#include "wakeup_source_iter.skel.h"
> +
> +#include <fcntl.h>
> +#include <stdbool.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <unistd.h>
> +
> +
> +/* Sleep for 10ms to ensure active time is > 0 after converting ns to ms*/
> +#define TEST_SLEEP_US 10000
> +#define TEST_SLEEP_MS (TEST_SLEEP_US / 1000)
> +#define WAKEUP_SOURCE_NAME_LEN 32
> +
> +static const char test_ws_name[] = "bpf_selftest_ws";
> +static bool test_ws_created;
> +
> +/*
> + * Creates a new wakeup source by writing to /sys/power/wake_lock.
> + * This lock persists until explicitly unlocked.
> + */
> +static int lock_ws(const char *name)
> +{
> + int fd;
> + ssize_t bytes;
> +
> + fd = open("/sys/power/wake_lock", O_WRONLY);
> + if (!ASSERT_OK_FD(fd, "open /sys/power/wake_lock"))
> + return -1;
> +
> + bytes = write(fd, name, strlen(name));
> + close(fd);
> + if (!ASSERT_EQ(bytes, strlen(name), "write to wake_lock"))
> + return -1;
> +
> + return 0;
> +}
> +
> +/*
> + * Destroys the ws by writing the same name to /sys/power/wake_unlock.
> + */
> +static void unlock_ws(const char *name)
> +{
> + int fd;
> +
> + fd = open("/sys/power/wake_unlock", O_WRONLY);
> + if (!ASSERT_OK_FD(fd, "open /sys/power/wake_unlock"))
> + goto cleanup;
> +
> + write(fd, name, strlen(name));
> +
> +cleanup:
> + if (fd)
> + close(fd);
> +}
> +
> +/*
> + * Setups for testing ws iterators. Will run once prior to suite of tests.
> + */
> +static int setup_test_ws(void)
> +{
> + if (lock_ws(test_ws_name))
> + return -1;
> + test_ws_created = true;
> +
> + return 0;
> +}
> +
> +/*
> + * Tears down and cleanups testing ws iterators. WIll run once after the
> suite
> + * of tests.
> + */
> +static void teardown_test_ws(void)
> +{
> + if (!test_ws_created)
> + return;
> + unlock_ws(test_ws_name);
> + test_ws_created = false;
> +}
> +
> +struct WakeupSourceInfo {
> + char name[WAKEUP_SOURCE_NAME_LEN];
> + unsigned long active_count;
> + long active_time_ms;
> + unsigned long event_count;
> + unsigned long expire_count;
> + long last_change_ms;
> + long max_time_ms;
> + long prevent_sleep_time_ms;
> + long total_time_ms;
> + unsigned long wakeup_count;
> +};
> +
> +/*
> + * Reads and parses one wakeup_source record from the iterator file.
> + * A record is a single space-delimited line.
> + * Returns true on success, false on EOF. Asserts internally on errors.
> + */
> +static bool read_ws_info(FILE *iter_file, struct WakeupSourceInfo *ws_info,
> + char **line)
> +{
> + size_t linesize;
> + int items;
> +
> + if (getline(line, &linesize, iter_file) == -1)
> + return false;
> +
> + (*line)[strcspn(*line, "\n")] = 0;
> +
> + items = sscanf(*line, "%s %lu %ld %lu %lu %ld %ld %ld %ld %lu",
> + ws_info->name, &ws_info->active_count,
> + &ws_info->active_time_ms, &ws_info->event_count,
> + &ws_info->expire_count, &ws_info->last_change_ms,
> + &ws_info->max_time_ms, &ws_info->prevent_sleep_time_ms,
> + &ws_info->total_time_ms, &ws_info->wakeup_count);
> +
> + if (!ASSERT_EQ(items, 10, "read wakeup source info"))
> + return false;
> +
> + if (!ASSERT_LT(strlen(ws_info->name), WAKEUP_SOURCE_NAME_LEN,
> + "name length"))
> + return false;
> +
> + return true;
> +}
> +
> +static int get_ws_iter_stream(struct wakeup_source_iter *skel, int *iter_fd,
> + FILE **iter_file)
> +{
> + *iter_fd = bpf_iter_create(
> + bpf_link__fd(skel->links.wakeup_source_collector));
> + if (!ASSERT_OK_FD(*iter_fd, "iter_create"))
> + return -1;
> +
> + *iter_file = fdopen(*iter_fd, "r");
> + if (!ASSERT_OK_PTR(*iter_file, "fdopen"))
> + return -1;
> +
> + return 0;
> +}
> +
> +static void subtest_ws_iter_check_active_count(struct wakeup_source_iter
> *skel)
> +{
> + static const char subtest_ws_name[] = "bpf_selftest_ws_active_count";
> + const int lock_unlock_cycles = 5;
> + struct WakeupSourceInfo ws_info;
> + char *line = NULL;
> + bool found_ws = false;
> + FILE *iter_file = NULL;
> + int iter_fd = -1;
> + int i;
> +
> + for (i = 0; i < lock_unlock_cycles; i++) {
> + if (!ASSERT_OK(lock_ws(subtest_ws_name), "lock_ws"))
> + goto cleanup;
> + unlock_ws(subtest_ws_name);
> + }
> +
> + if (!get_ws_iter_stream(skel, &iter_fd, &iter_file))
> + goto cleanup;
> +
> + while (read_ws_info(iter_file, &ws_info, &line)) {
> + if (strcmp(ws_info.name, subtest_ws_name) == 0) {
> + found_ws = true;
> + ASSERT_EQ(ws_info.active_count, lock_unlock_cycles,
> + "active_count check");
> + ASSERT_EQ(ws_info.wakeup_count, lock_unlock_cycles,
> + "wakeup_count check");
> + break;
> + }
> + }
> +
> + ASSERT_TRUE(found_ws, "found active_count test ws");
> +
> + free(line);
> +cleanup:
> + if (iter_file)
> + fclose(iter_file);
> + else if (iter_fd >= 0)
> + close(iter_fd);
> +}
> +
> +static void subtest_ws_iter_check_sleep_times(struct wakeup_source_iter
> *skel)
> +{
> + bool found_test_ws = false;
> + struct WakeupSourceInfo ws_info;
> + char *line = NULL;
> + FILE *iter_file;
> + int iter_fd;
> +
> + if (!get_ws_iter_stream(skel, &iter_fd, &iter_file))
> + goto cleanup;
> +
> + while (read_ws_info(iter_file, &ws_info, &line)) {
> + if (strcmp(ws_info.name, test_ws_name) == 0) {
> + found_test_ws = true;
> + ASSERT_GT(ws_info.last_change_ms, 0,
> + "Expected non-zero last change");
> + ASSERT_GE(ws_info.active_time_ms, TEST_SLEEP_MS,
> + "Expected active time >= TEST_SLEEP_MS");
> + ASSERT_GE(ws_info.max_time_ms, TEST_SLEEP_MS,
> + "Expected max time >= TEST_SLEEP_MS");
> + ASSERT_GE(ws_info.total_time_ms, TEST_SLEEP_MS,
> + "Expected total time >= TEST_SLEEP_MS");
> + break;
> + }
> + }
> +
> + ASSERT_TRUE(found_test_ws, "found_test_ws");
> +
> + free(line);
> +cleanup:
> + if (iter_file)
> + fclose(iter_file);
> + else if (iter_fd >= 0)
> + close(iter_fd);
> +}
> +
> +static void subtest_ws_iter_check_no_infinite_reads(
> + struct wakeup_source_iter *skel)
> +{
> + int iter_fd;
> + char buf[256];
> +
> + iter_fd =
> bpf_iter_create(bpf_link__fd(skel->links.wakeup_source_collector));
> + if (!ASSERT_OK_FD(iter_fd, "iter_create"))
> + return;
> +
> + while (read(iter_fd, buf, sizeof(buf)) > 0)
> + ;
> +
> + /* Final read should return 0 */
> + ASSERT_EQ(read(iter_fd, buf, sizeof(buf)), 0, "read");
> +
> + close(iter_fd);
> +}
> +
> +void test_wakeup_source_iter(void)
> +{
> + struct wakeup_source_iter *skel = NULL;
> +
> + if (geteuid() != 0) {
> + fprintf(stderr,
> + "Skipping wakeup_source_iter test, requires root\n");
> + test__skip();
> + return;
> + }
> +
> + skel = wakeup_source_iter__open_and_load();
> + if (!ASSERT_OK_PTR(skel, "wakeup_source_iter__open_and_load"))
> + return;
> +
> + if (!ASSERT_OK(setup_test_ws(), "setup_test_ws"))
> + goto destroy;
> +
> + if (!ASSERT_OK(wakeup_source_iter__attach(skel), "skel_attach"))
> + goto destroy;
> +
> + /*
> + * Sleep on O(ms) to ensure that time stats' resolution isn't lost
> when
> + * converting from ns to ms
> + */
> + usleep(TEST_SLEEP_US);
> +
> + if (test__start_subtest("active_count"))
> + subtest_ws_iter_check_active_count(skel);
> + if (test__start_subtest("sleep_times"))
> + subtest_ws_iter_check_sleep_times(skel);
> + if (test__start_subtest("no_infinite_reads"))
> + subtest_ws_iter_check_no_infinite_reads(skel);
> +
> +destroy:
> + teardown_test_ws();
> + wakeup_source_iter__destroy(skel);
> +}
> diff --git a/tools/testing/selftests/bpf/progs/wakeup_source_iter.c
> b/tools/testing/selftests/bpf/progs/wakeup_source_iter.c
> new file mode 100644
> index 000000000000..9a377fd28f4e
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/wakeup_source_iter.c
> @@ -0,0 +1,70 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright (c) 2026 Google LLC */
> +#include <vmlinux.h>
> +#include <bpf/bpf_core_read.h>
> +#include <bpf/bpf_helpers.h>
> +
> +#define NSEC_PER_MS 1000000UL
> +#define WAKEUP_SOURCE_NAME_LEN 32
> +
> +char _license[] SEC("license") = "GPL";
> +
> +SEC("iter/wakeup_source")
> +int wakeup_source_collector(struct bpf_iter__wakeup_source *ctx)
> +{
> + const struct wakeup_source *ws = ctx->wakeup_source;
> + struct seq_file *seq = ctx->meta->seq;
> + char name[WAKEUP_SOURCE_NAME_LEN] = {'\0'};
> + const char *pname;
> + bool active, autosleep_enable;
> + u64 active_count, event_count, expire_count, wakeup_count;
> + s64 active_time, curr_time, last_change_time, max_time,
> + prevent_sleep_time, start_prevent_time, total_time;
> +
> + if (!ws)
> + return 0;
> +
> + active = BPF_CORE_READ_BITFIELD_PROBED(ws, active);
> + autosleep_enable = BPF_CORE_READ_BITFIELD_PROBED(ws,
> autosleep_enabled);
> + if (bpf_core_read(&pname, sizeof(pname), &ws->name) ||
> + bpf_probe_read_kernel_str(name, sizeof(name), pname) < 0 ||
> + bpf_core_read(&active_count, sizeof(active_count),
> &ws->active_count) ||
> + bpf_core_read(&event_count, sizeof(event_count),
> &ws->event_count) ||
> + bpf_core_read(&expire_count, sizeof(expire_count),
> &ws->expire_count) ||
> + bpf_core_read(&last_change_time, sizeof(last_change_time),
> &ws->last_time) ||
> + bpf_core_read(&max_time, sizeof(max_time), &ws->max_time) ||
> + bpf_core_read(
> + &prevent_sleep_time, sizeof(prevent_sleep_time),
> &ws->prevent_sleep_time) ||
> + bpf_core_read(
> + &start_prevent_time, sizeof(start_prevent_time),
> &ws->start_prevent_time) ||
> + bpf_core_read(&total_time, sizeof(total_time), &ws->total_time) ||
> + bpf_core_read(&wakeup_count, sizeof(wakeup_count),
> &ws->wakeup_count))
> + return 0;
you really don't need to do this for types returned from iterators,
try just accessing ws->start_prevent_time (and any other field)
directly
> +
> +
> + curr_time = bpf_ktime_get_ns();
> + active_time = 0;
> + if (active) {
> + active_time = curr_time - last_change_time;
> + total_time += active_time;
> + if (active_time > max_time)
> + max_time = active_time;
> + if (autosleep_enable)
> + prevent_sleep_time += curr_time - start_prevent_time;
> +
> + }
> +
> + BPF_SEQ_PRINTF(seq,
> + "%s %lu %ld %lu %lu %ld %ld %ld %ld %lu\n",
> + name,
> + active_count,
> + active_time / NSEC_PER_MS,
> + event_count,
> + expire_count,
> + last_change_time / NSEC_PER_MS,
> + max_time / NSEC_PER_MS,
> + prevent_sleep_time / NSEC_PER_MS,
> + total_time / NSEC_PER_MS,
> + wakeup_count);
> + return 0;
> +}
> --
> 2.52.0.457.g6b5491de43-goog
>
