Add selftests for the newly added bits iter.
- bits_iter_success
- percpu data extracted from the percpu struct should be expected
- RCU lock is not required
- It is fine without calling bpf_iter_cpumask_next()
- It can work as expected when invalid arguments are passed
- bits_iter_failure
- bpf_iter_bits_destroy() is required after calling
bpf_iter_bits_new()
- bpf_iter_bits_destroy() can only destroy an initialized iter
- bpf_iter_bits_next() must use an initialized iter
This test case can't work correctly on s390x for unknonw reason, thus it
is added to DENYLIST.s390x.
Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
---
tools/testing/selftests/bpf/DENYLIST.s390x | 3 +-
.../selftests/bpf/prog_tests/bits_iter.c | 137 ++++++++++++++++++
.../bpf/progs/test_bits_iter_failure.c | 54 +++++++
.../bpf/progs/test_bits_iter_success.c | 122 ++++++++++++++++
4 files changed, 315 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/selftests/bpf/prog_tests/bits_iter.c
create mode 100644 tools/testing/selftests/bpf/progs/test_bits_iter_failure.c
create mode 100644 tools/testing/selftests/bpf/progs/test_bits_iter_success.c
diff --git a/tools/testing/selftests/bpf/DENYLIST.s390x b/tools/testing/selftests/bpf/DENYLIST.s390x
index 1a63996c0304..0cd6d2bf1ff4 100644
--- a/tools/testing/selftests/bpf/DENYLIST.s390x
+++ b/tools/testing/selftests/bpf/DENYLIST.s390x
@@ -1,5 +1,6 @@
# TEMPORARY
# Alphabetical order
-exceptions # JIT does not support calling kfunc bpf_throw (exceptions)
+bits_iter # cpumask iter can't work as expected (?)
+exceptions # JIT does not support calling kfunc bpf_throw (exceptions)
get_stack_raw_tp # user_stack corrupted user stack (no backchain userspace)
stacktrace_build_id # compare_map_keys stackid_hmap vs. stackmap err -2 errno 2 (?)
diff --git a/tools/testing/selftests/bpf/prog_tests/bits_iter.c b/tools/testing/selftests/bpf/prog_tests/bits_iter.c
new file mode 100644
index 000000000000..ff4f921c91c9
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/bits_iter.c
@@ -0,0 +1,137 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2024 Yafang Shao <laoar.shao@xxxxxxxxx> */
+
+#define _GNU_SOURCE
+#include <sched.h>
+
+#include <test_progs.h>
+#include "test_bits_iter_success.skel.h"
+#include "test_bits_iter_failure.skel.h"
+#include "cgroup_helpers.h"
+
+static const char * const positive_testcases[] = {
+ "cpumask_memalloc",
+ "cpumask_copy",
+};
+
+static const char * const negative_testcases[] = {
+ "null_pointer",
+ "zero_bit",
+ "no_mem",
+};
+
+static int read_percpu_data(struct bpf_link *link)
+{
+ int iter_fd, len;
+ char buf[128];
+ size_t left;
+ char *p;
+
+ iter_fd = bpf_iter_create(bpf_link__fd(link));
+ if (!ASSERT_GE(iter_fd, 0, "iter_fd"))
+ return -1;
+
+ memset(buf, 0, sizeof(buf));
+ left = ARRAY_SIZE(buf);
+ p = buf;
+ while ((len = read(iter_fd, p, left)) > 0) {
+ p += len;
+ left -= len;
+ }
+
+ close(iter_fd);
+ return 0;
+}
+
+static void verify_iter_success(const char *prog_name, bool negative)
+{
+ DECLARE_LIBBPF_OPTS(bpf_iter_attach_opts, opts);
+ struct test_bits_iter_success *skel;
+ union bpf_iter_link_info linfo;
+ int cgrp_fd, err, i, nr_cpus;
+ struct bpf_program *prog;
+ struct bpf_link *link;
+ cpu_set_t set;
+
+ if (setup_cgroup_environment())
+ return;
+
+ /* Utilize the cgroup iter */
+ cgrp_fd = get_root_cgroup();
+ if (!ASSERT_GE(cgrp_fd, 0, "create_cgrp"))
+ goto cleanup;
+
+ skel = test_bits_iter_success__open();
+ if (!ASSERT_OK_PTR(skel, "cpumask_iter_success__open"))
+ goto close_fd;
+
+ skel->bss->pid = getpid();
+
+ err = test_bits_iter_success__load(skel);
+ if (!ASSERT_OK(err, "cpumask_iter_success__load"))
+ goto destroy;
+
+ prog = bpf_object__find_program_by_name(skel->obj, prog_name);
+ if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name"))
+ goto destroy;
+
+ memset(&linfo, 0, sizeof(linfo));
+ linfo.cgroup.cgroup_fd = cgrp_fd;
+ linfo.cgroup.order = BPF_CGROUP_ITER_SELF_ONLY;
+ opts.link_info = &linfo;
+ opts.link_info_len = sizeof(linfo);
+ link = bpf_program__attach_iter(prog, &opts);
+ if (!ASSERT_OK_PTR(link, "bpf_program__attach"))
+ goto destroy;
+
+ if (negative)
+ goto negative;
+
+ CPU_ZERO(&set);
+ nr_cpus = libbpf_num_possible_cpus();
+ /* To guarantee the success of "cpumask_copy" at all times */
+ if (nr_cpus > 16)
+ nr_cpus = 16;
+ for (i = 0; i < nr_cpus; i++)
+ CPU_SET(i, &set);
+ err = sched_setaffinity(skel->bss->pid, sizeof(set), &set);
+ if (!ASSERT_OK(err, "setaffinity_all_cpus"))
+ goto free_link;
+ err = read_percpu_data(link);
+ if (!ASSERT_OK(err, "read_percpu_data"))
+ goto free_link;
+
+negative:
+ ASSERT_OK(skel->bss->err, "not_zero");
+
+free_link:
+ bpf_link__destroy(link);
+destroy:
+ test_bits_iter_success__destroy(skel);
+close_fd:
+ close(cgrp_fd);
+cleanup:
+ cleanup_cgroup_environment();
+}
+
+void test_bits_iter(void)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(positive_testcases); i++) {
+ if (!test__start_subtest(positive_testcases[i]))
+ continue;
+
+ verify_iter_success(positive_testcases[i], false);
+ }
+
+ for (i = 0; i < ARRAY_SIZE(negative_testcases); i++) {
+ if (!test__start_subtest(negative_testcases[i]))
+ continue;
+
+ verify_iter_success(negative_testcases[i], true);
+ }
+
+ RUN_TESTS(test_bits_iter_success);
+ RUN_TESTS(test_bits_iter_failure);
+}
diff --git a/tools/testing/selftests/bpf/progs/test_bits_iter_failure.c b/tools/testing/selftests/bpf/progs/test_bits_iter_failure.c
new file mode 100644
index 000000000000..974d0b7a540e
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_bits_iter_failure.c
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2024 Yafang Shao <laoar.shao@xxxxxxxxx> */
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+#include "bpf_misc.h"
+#include "task_kfunc_common.h"
+
+char _license[] SEC("license") = "GPL";
+
+int bpf_iter_bits_new(struct bpf_iter_bits *it, const void *unsafe_ptr__ign,
+ u32 nr_bits) __ksym __weak;
+int *bpf_iter_bits_next(struct bpf_iter_bits *it) __ksym __weak;
+void bpf_iter_bits_destroy(struct bpf_iter_bits *it) __ksym __weak;
+
+SEC("iter.s/cgroup")
+__failure __msg("Unreleased reference id=3 alloc_insn=10")
+int BPF_PROG(no_destroy, struct bpf_iter_meta *meta, struct cgroup *cgrp)
+{
+ struct bpf_iter_bits it;
+ struct task_struct *p;
+
+ p = bpf_task_from_pid(1);
+ if (!p)
+ return 1;
+
+ bpf_iter_bits_new(&it, p->cpus_ptr, 8192);
+
+ bpf_iter_bits_next(&it);
+ bpf_task_release(p);
+ return 0;
+}
+
+SEC("iter/cgroup")
+__failure __msg("expected an initialized iter_bits as arg #1")
+int BPF_PROG(next_uninit, struct bpf_iter_meta *meta, struct cgroup *cgrp)
+{
+ struct bpf_iter_bits *it = NULL;
+
+ bpf_iter_bits_next(it);
+ return 0;
+}
+
+SEC("iter/cgroup")
+__failure __msg("expected an initialized iter_bits as arg #1")
+int BPF_PROG(destroy_uninit, struct bpf_iter_meta *meta, struct cgroup *cgrp)
+{
+ struct bpf_iter_bits it = {};
+
+ bpf_iter_bits_destroy(&it);
+ return 0;
+}
diff --git a/tools/testing/selftests/bpf/progs/test_bits_iter_success.c b/tools/testing/selftests/bpf/progs/test_bits_iter_success.c
new file mode 100644
index 000000000000..77081204dec3
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_bits_iter_success.c
@@ -0,0 +1,122 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2024 Yafang Shao <laoar.shao@xxxxxxxxx> */
+
+#include "vmlinux.h"
+#include <linux/const.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+#include "task_kfunc_common.h"
+
+char _license[] SEC("license") = "GPL";
+
+extern const struct rq runqueues __ksym __weak;
+
+int bpf_iter_bits_new(struct bpf_iter_bits *it, const void *unsafe_ptr__ign,
+ u32 nr_bits) __ksym __weak;
+int *bpf_iter_bits_next(struct bpf_iter_bits *it) __ksym __weak;
+void bpf_iter_bits_destroy(struct bpf_iter_bits *it) __ksym __weak;
+
+int pid, err;
+
+static int cpumask_iter(struct bpf_iter_meta *meta, struct cgroup *cgrp, u32 nr_cpus)
+{
+ struct task_struct *p;
+ u32 nr_running = 0;
+ struct rq *rq;
+ int *cpu;
+
+ /* epilogue */
+ if (!cgrp)
+ return 0;
+
+ p = bpf_task_from_pid(pid);
+ if (!p)
+ return 1;
+
+ bpf_for_each(bits, cpu, p->cpus_ptr, nr_cpus) {
+ rq = (struct rq *)bpf_per_cpu_ptr(&runqueues, *cpu);
+ /* Every valid CPU should possess a runqueue, even in the event of being offline */
+ if (!rq)
+ break;
+ nr_running += rq->nr_running;
+ }
+ if (nr_running == 0)
+ err = 1;
+ bpf_task_release(p);
+ return 0;
+}
+
+SEC("iter.s/cgroup")
+int BPF_PROG(cpumask_memalloc, struct bpf_iter_meta *meta, struct cgroup *cgrp)
+{
+ return cpumask_iter(meta, cgrp, 128);
+}
+
+SEC("iter.s/cgroup")
+int BPF_PROG(cpumask_copy, struct bpf_iter_meta *meta, struct cgroup *cgrp)
+{
+ return cpumask_iter(meta, cgrp, 16);
+}
+
+SEC("iter.s/cgroup")
+int BPF_PROG(null_pointer, struct bpf_iter_meta *meta, struct cgroup *cgrp)
+{
+ int *cpu;
+
+ bpf_for_each(bits, cpu, NULL, 8192)
+ err++;
+ return 0;
+}
+
+SEC("iter.s/cgroup")
+int BPF_PROG(zero_bit, struct bpf_iter_meta *meta, struct cgroup *cgrp)
+{
+ struct task_struct *p;
+ int *cpu;
+
+ p = bpf_task_from_pid(pid);
+ if (!p)
+ return 1;
+
+ bpf_for_each(bits, cpu, p->cpus_ptr, 0)
+ err++;
+ bpf_task_release(p);
+ return 0;
+}
+
+SEC("iter.s/cgroup")
+int BPF_PROG(no_mem, struct bpf_iter_meta *meta, struct cgroup *cgrp)
+{
+ struct task_struct *p;
+ int *cpu;
+
+ p = bpf_task_from_pid(pid);
+ if (!p)
+ return 1;
+
+ /* The max number of memalloc is 4096, thus it will fail to allocate (8192 * 8) */
+ bpf_for_each(bits, cpu, p->cpus_ptr, 8192 * 8)
+ err++;
+ bpf_task_release(p);
+ return 0;
+}
+
+SEC("iter.s/cgroup")
+int BPF_PROG(no_next, struct bpf_iter_meta *meta, struct cgroup *cgrp)
+{
+ struct bpf_iter_bits it;
+ struct task_struct *p;
+
+ p = bpf_task_from_pid(1);
+ if (!p)
+ return 1;
+
+ bpf_iter_bits_new(&it, p->cpus_ptr, 8192);
+
+ /* It functions properly without invoking bpf_iter_bits_next(). */
+
+ bpf_iter_bits_destroy(&it);
+ bpf_task_release(p);
+ return 0;
+}
--
2.39.1
