From: Mykyta Yatsenko Introducing selftests that check BPF task work scheduling mechanism. Validate that verifier does not accepts incorrect calls to bpf_task_work_schedule kfunc. Signed-off-by: Mykyta Yatsenko --- .../selftests/bpf/prog_tests/test_task_work.c | 149 ++++++++++++++++++ tools/testing/selftests/bpf/progs/task_work.c | 108 +++++++++++++ .../selftests/bpf/progs/task_work_fail.c | 98 ++++++++++++ 3 files changed, 355 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/test_task_work.c create mode 100644 tools/testing/selftests/bpf/progs/task_work.c create mode 100644 tools/testing/selftests/bpf/progs/task_work_fail.c diff --git a/tools/testing/selftests/bpf/prog_tests/test_task_work.c b/tools/testing/selftests/bpf/prog_tests/test_task_work.c new file mode 100644 index 000000000000..9c3c7a46a827 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/test_task_work.c @@ -0,0 +1,149 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */ +#include +#include +#include +#include "task_work.skel.h" +#include "task_work_fail.skel.h" +#include +#include +#include +#include + +static int perf_event_open(__u32 type, __u64 config, int pid) +{ + struct perf_event_attr attr = { + .type = type, + .config = config, + .size = sizeof(struct perf_event_attr), + .sample_period = 100000, + }; + + return syscall(__NR_perf_event_open, &attr, pid, -1, -1, 0); +} + +struct elem { + char data[128]; + struct bpf_task_work tw; +}; + +static int verify_map(struct bpf_map *map, const char *expected_data) +{ + int err; + struct elem value; + int processed_values = 0; + int k, sz; + + sz = bpf_map__max_entries(map); + for (k = 0; k < sz; ++k) { + err = bpf_map__lookup_elem(map, &k, sizeof(int), &value, sizeof(struct elem), 0); + if (err) + continue; + if (!ASSERT_EQ(strcmp(expected_data, value.data), 0, "map data")) { + fprintf(stderr, "expected '%s', found '%s' in %s map", expected_data, + value.data, bpf_map__name(map)); + return 2; + } + processed_values++; + } + + return processed_values == 0; +} + +static void task_work_run(const char *prog_name, const char *map_name) +{ + struct task_work *skel; + struct bpf_program *prog; + struct bpf_map *map; + struct bpf_link *link; + int err, pe_fd = 0, pid, status, pipefd[2]; + char user_string[] = "hello world"; + + if (!ASSERT_NEQ(pipe(pipefd), -1, "pipe")) + return; + + pid = fork(); + if (pid == 0) { + __u64 num = 1; + int i; + char buf; + + close(pipefd[1]); + read(pipefd[0], &buf, sizeof(buf)); + close(pipefd[0]); + + for (i = 0; i < 10000; ++i) + num *= time(0) % 7; + (void)num; + exit(0); + } + skel = task_work__open(); + if (!ASSERT_OK_PTR(skel, "task_work__open")) + return; + + bpf_object__for_each_program(prog, skel->obj) { + bpf_program__set_autoload(prog, false); + } + + prog = bpf_object__find_program_by_name(skel->obj, prog_name); + if (!ASSERT_OK_PTR(prog, "prog_name")) + goto cleanup; + bpf_program__set_autoload(prog, true); + bpf_program__set_type(prog, BPF_PROG_TYPE_PERF_EVENT); + skel->bss->user_ptr = (char *)user_string; + + err = task_work__load(skel); + if (!ASSERT_OK(err, "skel_load")) + goto cleanup; + + pe_fd = perf_event_open(PERF_TYPE_HARDWARE, PERF_COUNT_HW_CPU_CYCLES, pid); + if (pe_fd == -1 && (errno == ENOENT || errno == EOPNOTSUPP)) { + printf("%s:SKIP:no PERF_COUNT_HW_CPU_CYCLES\n", __func__); + test__skip(); + goto cleanup; + } + if (!ASSERT_NEQ(pe_fd, -1, "pe_fd")) { + fprintf(stderr, "perf_event_open errno: %d, pid: %d\n", errno, pid); + goto cleanup; + } + + link = bpf_program__attach_perf_event(prog, pe_fd); + if (!ASSERT_OK_PTR(link, "attach_perf_event")) + goto cleanup; + + close(pipefd[0]); + write(pipefd[1], user_string, 1); + close(pipefd[1]); + /* Wait to collect some samples */ + waitpid(pid, &status, 0); + pid = 0; + map = bpf_object__find_map_by_name(skel->obj, map_name); + if (!ASSERT_OK_PTR(map, "find map_name")) + goto cleanup; + if (!ASSERT_OK(verify_map(map, user_string), "verify map")) + goto cleanup; +cleanup: + if (pe_fd >= 0) + close(pe_fd); + task_work__destroy(skel); + if (pid) { + close(pipefd[0]); + write(pipefd[1], user_string, 1); + close(pipefd[1]); + waitpid(pid, &status, 0); + } +} + +void test_task_work(void) +{ + if (test__start_subtest("test_task_work_hash_map")) + task_work_run("oncpu_hash_map", "hmap"); + + if (test__start_subtest("test_task_work_array_map")) + task_work_run("oncpu_array_map", "arrmap"); + + if (test__start_subtest("test_task_work_lru_map")) + task_work_run("oncpu_lru_map", "lrumap"); + + RUN_TESTS(task_work_fail); +} diff --git a/tools/testing/selftests/bpf/progs/task_work.c b/tools/testing/selftests/bpf/progs/task_work.c new file mode 100644 index 000000000000..5e761b4a5fd1 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/task_work.c @@ -0,0 +1,108 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */ + +#include +#include +#include +#include +#include +#include "bpf_misc.h" +#include "errno.h" + +char _license[] SEC("license") = "GPL"; + +const void *user_ptr = NULL; + +struct elem { + char data[128]; + struct bpf_task_work tw; +}; + +struct { + __uint(type, BPF_MAP_TYPE_HASH); + __uint(map_flags, BPF_F_NO_PREALLOC); + __uint(max_entries, 1); + __type(key, int); + __type(value, struct elem); +} hmap SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __uint(max_entries, 1); + __type(key, int); + __type(value, struct elem); +} arrmap SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_LRU_HASH); + __uint(max_entries, 1); + __type(key, int); + __type(value, struct elem); +} lrumap SEC(".maps"); + +static void process_work(struct bpf_map *map, void *key, void *value) +{ + struct elem *work = value; + + bpf_copy_from_user_str(work->data, sizeof(work->data), (const void *)user_ptr, 0); +} + +int key = 0; + +SEC("perf_event") +int oncpu_hash_map(struct pt_regs *args) +{ + struct elem empty_work = { .data = { 0 } }; + struct elem *work; + struct task_struct *task; + int err; + + task = bpf_get_current_task_btf(); + err = bpf_map_update_elem(&hmap, &key, &empty_work, BPF_NOEXIST); + if (err) + return 0; + work = bpf_map_lookup_elem(&hmap, &key); + if (!work) + return 0; + + bpf_task_work_schedule_resume(task, &work->tw, (struct bpf_map *)&hmap, process_work, NULL); + return 0; +} + +SEC("perf_event") +int oncpu_array_map(struct pt_regs *args) +{ + struct elem *work; + struct task_struct *task; + + task = bpf_get_current_task_btf(); + work = bpf_map_lookup_elem(&arrmap, &key); + if (!work) + return 0; + bpf_task_work_schedule_signal(task, &work->tw, (struct bpf_map *)&arrmap, process_work, + NULL); + return 0; +} + +SEC("perf_event") +int oncpu_lru_map(struct pt_regs *args) +{ + struct elem empty_work = { .data = { 0 } }; + struct elem *work; + struct task_struct *task; + int err; + + task = bpf_get_current_task_btf(); + work = bpf_map_lookup_elem(&lrumap, &key); + if (work) + return 0; + err = bpf_map_update_elem(&lrumap, &key, &empty_work, BPF_NOEXIST); + if (err) + return 0; + work = bpf_map_lookup_elem(&lrumap, &key); + if (!work || work->data[0]) + return 0; + bpf_task_work_schedule_resume(task, &work->tw, (struct bpf_map *)&lrumap, process_work, + NULL); + return 0; +} diff --git a/tools/testing/selftests/bpf/progs/task_work_fail.c b/tools/testing/selftests/bpf/progs/task_work_fail.c new file mode 100644 index 000000000000..fca7052b805e --- /dev/null +++ b/tools/testing/selftests/bpf/progs/task_work_fail.c @@ -0,0 +1,98 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */ + +#include +#include +#include +#include +#include +#include "bpf_misc.h" + +char _license[] SEC("license") = "GPL"; + +const void *user_ptr = NULL; + +struct elem { + char data[128]; + struct bpf_task_work tw; +}; + +struct { + __uint(type, BPF_MAP_TYPE_HASH); + __uint(map_flags, BPF_F_NO_PREALLOC); + __uint(max_entries, 1); + __type(key, int); + __type(value, struct elem); +} hmap SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __uint(max_entries, 1); + __type(key, int); + __type(value, struct elem); +} arrmap SEC(".maps"); + +static void process_work(struct bpf_map *map, void *key, void *value) +{ + struct elem *work = value; + + bpf_copy_from_user_str(work->data, sizeof(work->data), (const void *)user_ptr, 0); +} + +int key = 0; + +SEC("perf_event") +__failure __msg("doesn't match map pointer in R3") +int mismatch_map(struct pt_regs *args) +{ + struct elem *work; + struct task_struct *task; + + task = bpf_get_current_task_btf(); + work = bpf_map_lookup_elem(&arrmap, &key); + if (!work) + return 0; + bpf_task_work_schedule_resume(task, &work->tw, (struct bpf_map *)&hmap, + process_work, NULL); + return 0; +} + +SEC("perf_event") +__failure __msg("arg#1 doesn't point to a map value") +int no_map_task_work(struct pt_regs *args) +{ + struct task_struct *task; + struct bpf_task_work tw; + + task = bpf_get_current_task_btf(); + bpf_task_work_schedule_resume(task, &tw, (struct bpf_map *)&hmap, + process_work, NULL); + return 0; +} + +SEC("perf_event") +__failure __msg("Possibly NULL pointer passed to trusted arg1") +int task_work_null(struct pt_regs *args) +{ + struct task_struct *task; + + task = bpf_get_current_task_btf(); + bpf_task_work_schedule_resume(task, NULL, (struct bpf_map *)&hmap, + process_work, NULL); + return 0; +} + +SEC("perf_event") +__failure __msg("Possibly NULL pointer passed to trusted arg2") +int map_null(struct pt_regs *args) +{ + struct elem *work; + struct task_struct *task; + + task = bpf_get_current_task_btf(); + work = bpf_map_lookup_elem(&arrmap, &key); + if (!work) + return 0; + bpf_task_work_schedule_resume(task, &work->tw, NULL, process_work, NULL); + return 0; +} -- 2.50.1