Introduce a set of BPF selftests to verify the safety and functionality of wakeup_source kfuncs.
The suite includes: 1. A functional test (test_wakeup_source.c) that iterates over the global wakeup_sources list. It uses CO-RE to read timing statistics and validates them in user-space via the BPF ring buffer. 2. A negative test suite (wakeup_source_fail.c) ensuring the BPF verifier correctly enforces reference tracking and type safety. 3. Enable CONFIG_PM_WAKELOCKS in the test config, allowing creation of wakeup sources via /sys/power/wake_lock. A shared header (wakeup_source.h) is introduced to ensure consistent memory layout for the Ring Buffer data between BPF and user-space. Signed-off-by: Samuel Wu <[email protected]> --- tools/testing/selftests/bpf/config | 3 +- .../selftests/bpf/prog_tests/wakeup_source.c | 101 +++++++++++++++++ .../selftests/bpf/progs/test_wakeup_source.c | 107 ++++++++++++++++++ .../selftests/bpf/progs/wakeup_source.h | 22 ++++ .../selftests/bpf/progs/wakeup_source_fail.c | 63 +++++++++++ 5 files changed, 295 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/wakeup_source.c create mode 100644 tools/testing/selftests/bpf/progs/test_wakeup_source.c create mode 100644 tools/testing/selftests/bpf/progs/wakeup_source.h create mode 100644 tools/testing/selftests/bpf/progs/wakeup_source_fail.c diff --git a/tools/testing/selftests/bpf/config b/tools/testing/selftests/bpf/config index 24855381290d..bac60b444551 100644 --- a/tools/testing/selftests/bpf/config +++ b/tools/testing/selftests/bpf/config @@ -130,4 +130,5 @@ CONFIG_INFINIBAND=y CONFIG_SMC=y CONFIG_SMC_HS_CTRL_BPF=y CONFIG_DIBS=y -CONFIG_DIBS_LO=y \ No newline at end of file +CONFIG_DIBS_LO=y +CONFIG_PM_WAKELOCKS=y diff --git a/tools/testing/selftests/bpf/prog_tests/wakeup_source.c b/tools/testing/selftests/bpf/prog_tests/wakeup_source.c new file mode 100644 index 000000000000..ff2899cbf3a8 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/wakeup_source.c @@ -0,0 +1,101 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright 2026 Google LLC */ + +#include <test_progs.h> +#include <fcntl.h> +#include "test_wakeup_source.skel.h" +#include "wakeup_source_fail.skel.h" +#include "progs/wakeup_source.h" + +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; +} + +static void unlock_ws(const char *name) +{ + int fd; + + fd = open("/sys/power/wake_unlock", O_WRONLY); + if (fd < 0) + return; + + write(fd, name, strlen(name)); + close(fd); +} + +struct rb_ctx { + const char *name; + bool found; + long long active_time_ns; + long long total_time_ns; +}; + +static int process_sample(void *ctx, void *data, size_t len) +{ + struct rb_ctx *rb_ctx = ctx; + struct wakeup_event_t *e = data; + + if (strcmp(e->name, rb_ctx->name) == 0) { + rb_ctx->found = true; + rb_ctx->active_time_ns = e->active_time_ns; + rb_ctx->total_time_ns = e->total_time_ns; + } + return 0; +} + +void test_wakeup_source(void) +{ + if (test__start_subtest("iterate_and_verify_times")) { + struct test_wakeup_source *skel; + struct ring_buffer *rb = NULL; + struct rb_ctx rb_ctx = { + .name = "bpf_selftest_ws_times", + .found = false, + }; + int err; + + skel = test_wakeup_source__open_and_load(); + if (!ASSERT_OK_PTR(skel, "skel_open_and_load")) + return; + + rb = ring_buffer__new(bpf_map__fd(skel->maps.rb), process_sample, &rb_ctx, NULL); + if (!ASSERT_OK_PTR(rb, "ring_buffer__new")) + goto destroy; + + /* Create a temporary wakeup source */ + if (!ASSERT_OK(lock_ws(rb_ctx.name), "lock_ws")) + goto unlock; + + err = bpf_prog_test_run_opts(bpf_program__fd( + skel->progs.iterate_wakeupsources), NULL); + ASSERT_OK(err, "bpf_prog_test_run"); + + ring_buffer__consume(rb); + + ASSERT_TRUE(rb_ctx.found, "found_test_ws_in_rb"); + ASSERT_GT(rb_ctx.active_time_ns, 0, "active_time_gt_0"); + ASSERT_GT(rb_ctx.total_time_ns, 0, "total_time_gt_0"); + +unlock: + unlock_ws(rb_ctx.name); +destroy: + if (rb) + ring_buffer__free(rb); + test_wakeup_source__destroy(skel); + } + + RUN_TESTS(wakeup_source_fail); +} diff --git a/tools/testing/selftests/bpf/progs/test_wakeup_source.c b/tools/testing/selftests/bpf/progs/test_wakeup_source.c new file mode 100644 index 000000000000..fa35156e31d2 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_wakeup_source.c @@ -0,0 +1,107 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright 2026 Google LLC */ + +#include "vmlinux.h" +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_core_read.h> +#include "bpf_experimental.h" +#include "bpf_misc.h" +#include "wakeup_source.h" + +#define MAX_LOOP_ITER 1000 +#define RB_SIZE (16384 * 4) + +struct wakeup_source___local { + const char *name; + unsigned long active_count; + unsigned long event_count; + unsigned long wakeup_count; + unsigned long expire_count; + ktime_t last_time; + ktime_t max_time; + ktime_t total_time; + ktime_t start_prevent_time; + ktime_t prevent_sleep_time; + struct list_head entry; + bool active:1; + bool autosleep_enabled:1; +} __attribute__((preserve_access_index)); + +struct { + __uint(type, BPF_MAP_TYPE_RINGBUF); + __uint(max_entries, RB_SIZE); +} rb SEC(".maps"); + +struct bpf_ws_lock; +struct bpf_ws_lock *bpf_wakeup_sources_read_lock(void) __ksym; +void bpf_wakeup_sources_read_unlock(struct bpf_ws_lock *lock) __ksym; +struct list_head *bpf_wakeup_sources_get_head(void) __ksym; + +SEC("syscall") +__success __retval(0) +int iterate_wakeupsources(void *ctx) +{ + struct list_head *head = bpf_wakeup_sources_get_head(); + struct list_head *pos = head; + struct bpf_ws_lock *lock; + int i; + + lock = bpf_wakeup_sources_read_lock(); + if (!lock) + return 0; + + bpf_for(i, 0, MAX_LOOP_ITER) { + if (bpf_core_read(&pos, sizeof(pos), &pos->next) || !pos || pos == head) + break; + + struct wakeup_event_t *e = bpf_ringbuf_reserve(&rb, sizeof(*e), 0); + + if (!e) + break; + + struct wakeup_source___local *ws = container_of( + pos, struct wakeup_source___local, entry); + s64 active_time = 0; + bool active = BPF_CORE_READ_BITFIELD_PROBED(ws, active); + bool autosleep_enable = BPF_CORE_READ_BITFIELD_PROBED(ws, autosleep_enabled); + s64 last_time = BPF_CORE_READ(ws, last_time); + s64 max_time = BPF_CORE_READ(ws, max_time); + s64 prevent_sleep_time = BPF_CORE_READ(ws, prevent_sleep_time); + s64 total_time = BPF_CORE_READ(ws, total_time); + + if (active) { + s64 curr_time = bpf_ktime_get_ns(); + s64 prevent_time = BPF_CORE_READ(ws, start_prevent_time); + + if (curr_time > last_time) + active_time = curr_time - last_time; + + total_time += active_time; + if (active_time > max_time) + max_time = active_time; + if (autosleep_enable && curr_time > prevent_time) + prevent_sleep_time += curr_time - prevent_time; + } + + e->active_count = BPF_CORE_READ(ws, active_count); + e->active_time_ns = active_time; + e->event_count = BPF_CORE_READ(ws, event_count); + e->expire_count = BPF_CORE_READ(ws, expire_count); + e->last_time_ns = last_time; + e->max_time_ns = max_time; + e->prevent_sleep_time_ns = prevent_sleep_time; + e->total_time_ns = total_time; + e->wakeup_count = BPF_CORE_READ(ws, wakeup_count); + + if (bpf_probe_read_kernel_str( + e->name, WAKEUP_NAME_LEN, BPF_CORE_READ(ws, name)) < 0) + e->name[0] = '\0'; + + bpf_ringbuf_submit(e, 0); + } + + bpf_wakeup_sources_read_unlock(lock); + return 0; +} + +char _license[] SEC("license") = "GPL"; diff --git a/tools/testing/selftests/bpf/progs/wakeup_source.h b/tools/testing/selftests/bpf/progs/wakeup_source.h new file mode 100644 index 000000000000..cd74de92c82f --- /dev/null +++ b/tools/testing/selftests/bpf/progs/wakeup_source.h @@ -0,0 +1,22 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* Copyright 2026 Google LLC */ + +#ifndef __WAKEUP_SOURCE_H__ +#define __WAKEUP_SOURCE_H__ + +#define WAKEUP_NAME_LEN 128 + +struct wakeup_event_t { + unsigned long active_count; + long long active_time_ns; + unsigned long event_count; + unsigned long expire_count; + long long last_time_ns; + long long max_time_ns; + long long prevent_sleep_time_ns; + long long total_time_ns; + unsigned long wakeup_count; + char name[WAKEUP_NAME_LEN]; +}; + +#endif /* __WAKEUP_SOURCE_H__ */ diff --git a/tools/testing/selftests/bpf/progs/wakeup_source_fail.c b/tools/testing/selftests/bpf/progs/wakeup_source_fail.c new file mode 100644 index 000000000000..a569c9d53d21 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/wakeup_source_fail.c @@ -0,0 +1,63 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright 2026 Google LLC */ + +#include <vmlinux.h> +#include <bpf/bpf_helpers.h> +#include "bpf_misc.h" + +struct bpf_ws_lock; + +struct bpf_ws_lock *bpf_wakeup_sources_read_lock(void) __ksym; +void bpf_wakeup_sources_read_unlock(struct bpf_ws_lock *lock) __ksym; + +SEC("syscall") +__failure __msg("BPF_EXIT instruction in main prog would lead to reference leak") +int wakeup_source_lock_no_unlock(void *ctx) +{ + struct bpf_ws_lock *lock; + + lock = bpf_wakeup_sources_read_lock(); + if (!lock) + return 0; + + return 0; +} + +SEC("syscall") +__failure __msg("access beyond struct") +int wakeup_source_access_lock_fields(void *ctx) +{ + struct bpf_ws_lock *lock; + int val; + + lock = bpf_wakeup_sources_read_lock(); + if (!lock) + return 0; + + val = *(int *)lock; + + bpf_wakeup_sources_read_unlock(lock); + return val; +} + +SEC("syscall") +__failure __msg("type=scalar expected=fp") +int wakeup_source_unlock_no_lock(void *ctx) +{ + struct bpf_ws_lock *lock = (void *)0x1; + + bpf_wakeup_sources_read_unlock(lock); + + return 0; +} + +SEC("syscall") +__failure __msg("Possibly NULL pointer passed to trusted arg0") +int wakeup_source_unlock_null(void *ctx) +{ + bpf_wakeup_sources_read_unlock(NULL); + + return 0; +} + +char _license[] SEC("license") = "GPL"; -- 2.53.0.1018.g2bb0e51243-goog
