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Byte-LabAlexei Starovoitov
Byte-Lab
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Alexei Starovoitov
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selftests/bpf: Add selftest suite for cpumask kfuncs
A recent patch added a new set of kfuncs for allocating, freeing, manipulating, and querying cpumasks. This patch adds a new 'cpumask' selftest suite which verifies their behavior. Signed-off-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/r/20230125143816.721952-5-void@manifault.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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‎tools/testing/selftests/bpf/DENYLIST.s390x‎

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@@ -13,6 +13,7 @@ cgroup_hierarchical_stats # JIT does not support calling kernel f
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cgrp_kfunc # JIT does not support calling kernel function
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cgrp_local_storage # prog_attach unexpected error: -524 (trampoline)
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core_read_macros # unknown func bpf_probe_read#4 (overlapping)
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cpumask # JIT does not support calling kernel function
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d_path # failed to auto-attach program 'prog_stat': -524 (trampoline)
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decap_sanity # JIT does not support calling kernel function (kfunc)
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deny_namespace # failed to attach: ERROR: strerror_r(-524)=22 (trampoline)

‎tools/testing/selftests/bpf/prog_tests/cpumask.c‎

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// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
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#include <test_progs.h>
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#include "cpumask_failure.skel.h"
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#include "cpumask_success.skel.h"
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static const char * const cpumask_success_testcases[] = {
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"test_alloc_free_cpumask",
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"test_set_clear_cpu",
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"test_setall_clear_cpu",
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"test_first_firstzero_cpu",
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"test_test_and_set_clear",
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"test_and_or_xor",
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"test_intersects_subset",
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"test_copy_any_anyand",
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"test_insert_leave",
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"test_insert_remove_release",
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"test_insert_kptr_get_release",
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};
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static void verify_success(const char *prog_name)
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{
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struct cpumask_success *skel;
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struct bpf_program *prog;
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struct bpf_link *link = NULL;
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pid_t child_pid;
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int status;
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skel = cpumask_success__open();
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if (!ASSERT_OK_PTR(skel, "cpumask_success__open"))
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return;
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skel->bss->pid = getpid();
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skel->bss->nr_cpus = libbpf_num_possible_cpus();
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cpumask_success__load(skel);
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if (!ASSERT_OK_PTR(skel, "cpumask_success__load"))
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goto cleanup;
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prog = bpf_object__find_program_by_name(skel->obj, prog_name);
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if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name"))
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goto cleanup;
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link = bpf_program__attach(prog);
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if (!ASSERT_OK_PTR(link, "bpf_program__attach"))
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goto cleanup;
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child_pid = fork();
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if (!ASSERT_GT(child_pid, -1, "child_pid"))
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goto cleanup;
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if (child_pid == 0)
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_exit(0);
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waitpid(child_pid, &status, 0);
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ASSERT_OK(skel->bss->err, "post_wait_err");
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cleanup:
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bpf_link__destroy(link);
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cpumask_success__destroy(skel);
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}
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void test_cpumask(void)
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{
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int i;
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for (i = 0; i < ARRAY_SIZE(cpumask_success_testcases); i++) {
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if (!test__start_subtest(cpumask_success_testcases[i]))
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continue;
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verify_success(cpumask_success_testcases[i]);
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}
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RUN_TESTS(cpumask_failure);
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}

‎tools/testing/selftests/bpf/progs/cpumask_common.h‎

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/* SPDX-License-Identifier: GPL-2.0 */
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/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
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#ifndef _CPUMASK_COMMON_H
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#define _CPUMASK_COMMON_H
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#include "errno.h"
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#include <stdbool.h>
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int err;
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struct __cpumask_map_value {
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struct bpf_cpumask __kptr_ref * cpumask;
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};
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struct array_map {
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__uint(type, BPF_MAP_TYPE_ARRAY);
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__type(key, int);
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__type(value, struct __cpumask_map_value);
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__uint(max_entries, 1);
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} __cpumask_map SEC(".maps");
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struct bpf_cpumask *bpf_cpumask_create(void) __ksym;
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void bpf_cpumask_release(struct bpf_cpumask *cpumask) __ksym;
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struct bpf_cpumask *bpf_cpumask_acquire(struct bpf_cpumask *cpumask) __ksym;
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struct bpf_cpumask *bpf_cpumask_kptr_get(struct bpf_cpumask **cpumask) __ksym;
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u32 bpf_cpumask_first(const struct cpumask *cpumask) __ksym;
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u32 bpf_cpumask_first_zero(const struct cpumask *cpumask) __ksym;
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void bpf_cpumask_set_cpu(u32 cpu, struct bpf_cpumask *cpumask) __ksym;
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void bpf_cpumask_clear_cpu(u32 cpu, struct bpf_cpumask *cpumask) __ksym;
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bool bpf_cpumask_test_cpu(u32 cpu, const struct cpumask *cpumask) __ksym;
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bool bpf_cpumask_test_and_set_cpu(u32 cpu, struct bpf_cpumask *cpumask) __ksym;
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bool bpf_cpumask_test_and_clear_cpu(u32 cpu, struct bpf_cpumask *cpumask) __ksym;
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void bpf_cpumask_setall(struct bpf_cpumask *cpumask) __ksym;
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void bpf_cpumask_clear(struct bpf_cpumask *cpumask) __ksym;
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bool bpf_cpumask_and(struct bpf_cpumask *cpumask,
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const struct cpumask *src1,
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const struct cpumask *src2) __ksym;
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void bpf_cpumask_or(struct bpf_cpumask *cpumask,
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const struct cpumask *src1,
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const struct cpumask *src2) __ksym;
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void bpf_cpumask_xor(struct bpf_cpumask *cpumask,
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const struct cpumask *src1,
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const struct cpumask *src2) __ksym;
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bool bpf_cpumask_equal(const struct cpumask *src1, const struct cpumask *src2) __ksym;
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bool bpf_cpumask_intersects(const struct cpumask *src1, const struct cpumask *src2) __ksym;
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bool bpf_cpumask_subset(const struct cpumask *src1, const struct cpumask *src2) __ksym;
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bool bpf_cpumask_empty(const struct cpumask *cpumask) __ksym;
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bool bpf_cpumask_full(const struct cpumask *cpumask) __ksym;
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void bpf_cpumask_copy(struct bpf_cpumask *dst, const struct cpumask *src) __ksym;
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u32 bpf_cpumask_any(const struct cpumask *src) __ksym;
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u32 bpf_cpumask_any_and(const struct cpumask *src1, const struct cpumask *src2) __ksym;
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static inline const struct cpumask *cast(struct bpf_cpumask *cpumask)
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{
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return (const struct cpumask *)cpumask;
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}
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static inline struct bpf_cpumask *create_cpumask(void)
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{
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struct bpf_cpumask *cpumask;
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cpumask = bpf_cpumask_create();
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if (!cpumask) {
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err = 1;
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return NULL;
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}
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if (!bpf_cpumask_empty(cast(cpumask))) {
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err = 2;
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bpf_cpumask_release(cpumask);
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return NULL;
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}
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return cpumask;
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}
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static inline struct __cpumask_map_value *cpumask_map_value_lookup(void)
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{
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u32 key = 0;
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return bpf_map_lookup_elem(&__cpumask_map, &key);
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}
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static inline int cpumask_map_insert(struct bpf_cpumask *mask)
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{
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struct __cpumask_map_value local, *v;
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long status;
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struct bpf_cpumask *old;
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u32 key = 0;
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local.cpumask = NULL;
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status = bpf_map_update_elem(&__cpumask_map, &key, &local, 0);
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if (status) {
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bpf_cpumask_release(mask);
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return status;
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}
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v = bpf_map_lookup_elem(&__cpumask_map, &key);
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if (!v) {
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bpf_cpumask_release(mask);
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return -ENOENT;
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}
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old = bpf_kptr_xchg(&v->cpumask, mask);
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if (old) {
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bpf_cpumask_release(old);
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return -EEXIST;
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}
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return 0;
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}
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#endif /* _CPUMASK_COMMON_H */

‎tools/testing/selftests/bpf/progs/cpumask_failure.c‎

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// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
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#include <vmlinux.h>
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#include <bpf/bpf_tracing.h>
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#include <bpf/bpf_helpers.h>
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#include "bpf_misc.h"
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#include "cpumask_common.h"
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char _license[] SEC("license") = "GPL";
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/* Prototype for all of the program trace events below:
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*
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* TRACE_EVENT(task_newtask,
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* TP_PROTO(struct task_struct *p, u64 clone_flags)
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*/
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SEC("tp_btf/task_newtask")
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__failure __msg("Unreleased reference")
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int BPF_PROG(test_alloc_no_release, struct task_struct *task, u64 clone_flags)
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{
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struct bpf_cpumask *cpumask;
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cpumask = create_cpumask();
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/* cpumask is never released. */
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return 0;
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}
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SEC("tp_btf/task_newtask")
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__failure __msg("NULL pointer passed to trusted arg0")
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int BPF_PROG(test_alloc_double_release, struct task_struct *task, u64 clone_flags)
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{
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struct bpf_cpumask *cpumask;
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cpumask = create_cpumask();
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/* cpumask is released twice. */
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bpf_cpumask_release(cpumask);
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bpf_cpumask_release(cpumask);
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return 0;
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}
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SEC("tp_btf/task_newtask")
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__failure __msg("bpf_cpumask_acquire args#0 expected pointer to STRUCT bpf_cpumask")
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int BPF_PROG(test_acquire_wrong_cpumask, struct task_struct *task, u64 clone_flags)
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{
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struct bpf_cpumask *cpumask;
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/* Can't acquire a non-struct bpf_cpumask. */
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cpumask = bpf_cpumask_acquire((struct bpf_cpumask *)task->cpus_ptr);
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return 0;
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}
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SEC("tp_btf/task_newtask")
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__failure __msg("bpf_cpumask_set_cpu args#1 expected pointer to STRUCT bpf_cpumask")
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int BPF_PROG(test_mutate_cpumask, struct task_struct *task, u64 clone_flags)
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{
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struct bpf_cpumask *cpumask;
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/* Can't set the CPU of a non-struct bpf_cpumask. */
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bpf_cpumask_set_cpu(0, (struct bpf_cpumask *)task->cpus_ptr);
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return 0;
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}
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SEC("tp_btf/task_newtask")
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__failure __msg("Unreleased reference")
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int BPF_PROG(test_insert_remove_no_release, struct task_struct *task, u64 clone_flags)
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{
74+
struct bpf_cpumask *cpumask;
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struct __cpumask_map_value *v;
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cpumask = create_cpumask();
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if (!cpumask)
79+
return 0;
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if (cpumask_map_insert(cpumask))
82+
return 0;
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v = cpumask_map_value_lookup();
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if (!v)
86+
return 0;
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cpumask = bpf_kptr_xchg(&v->cpumask, NULL);
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/* cpumask is never released. */
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return 0;
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}
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SEC("tp_btf/task_newtask")
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__failure __msg("Unreleased reference")
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int BPF_PROG(test_kptr_get_no_release, struct task_struct *task, u64 clone_flags)
97+
{
98+
struct bpf_cpumask *cpumask;
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struct __cpumask_map_value *v;
100+
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cpumask = create_cpumask();
102+
if (!cpumask)
103+
return 0;
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105+
if (cpumask_map_insert(cpumask))
106+
return 0;
107+
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v = cpumask_map_value_lookup();
109+
if (!v)
110+
return 0;
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cpumask = bpf_cpumask_kptr_get(&v->cpumask);
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/* cpumask is never released. */
115+
return 0;
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}
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SEC("tp_btf/task_newtask")
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__failure __msg("NULL pointer passed to trusted arg0")
120+
int BPF_PROG(test_cpumask_null, struct task_struct *task, u64 clone_flags)
121+
{
122+
/* NULL passed to KF_TRUSTED_ARGS kfunc. */
123+
bpf_cpumask_empty(NULL);
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return 0;
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}

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