This patch adds three tests to demonstrate these patterns and validating
correctness.
test1: We use bpf_for_each(process, task) to iterate all processed in the
system and search for the current process with a given pid.
test2: We create a cgroup and add the current process to the cgroup. In the
BPF program, we would use bpf_for_each(css_task, task, css) to iterate all
tasks under the cgroup. As expected, we would find the current process.
test3: We create a cgroup tree. In the BPF program, we use
bpf_for_each(css, pos, root) to iterate all descendant under the root with
post order. As expected, we would find all descendant and the last
iterating cgroup is root cgroup.
Signed-off-by: Chuyi Zhou <zhouchuyi@xxxxxxxxxxxxx>
---
.../testing/selftests/bpf/prog_tests/iters.c | 123 ++++++++++++++++++
.../testing/selftests/bpf/progs/iters_task.c | 83 ++++++++++++
2 files changed, 206 insertions(+)
create mode 100644 tools/testing/selftests/bpf/progs/iters_task.c
diff --git a/tools/testing/selftests/bpf/prog_tests/iters.c b/tools/testing/selftests/bpf/prog_tests/iters.c
index 10804ae5ae97..88fb565a3e97 100644
--- a/tools/testing/selftests/bpf/prog_tests/iters.c
+++ b/tools/testing/selftests/bpf/prog_tests/iters.c
@@ -2,12 +2,14 @@
/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
#include <test_progs.h>
+#include "cgroup_helpers.h"
#include "iters.skel.h"
#include "iters_state_safety.skel.h"
#include "iters_looping.skel.h"
#include "iters_num.skel.h"
#include "iters_testmod_seq.skel.h"
+#include "iters_task.skel.h"
static void subtest_num_iters(void)
{
@@ -90,6 +92,121 @@ static void subtest_testmod_seq_iters(void)
iters_testmod_seq__destroy(skel);
}
+static void subtest_process_iters(void)
+{
+ struct iters_task *skel;
+ int err;
+
+ skel = iters_task__open();
+ if (!ASSERT_OK_PTR(skel, "skel_open"))
+ goto cleanup;
+ bpf_program__set_autoload(skel->progs.iter_task_for_each, true);
+ err = iters_task__load(skel);
+ if (!ASSERT_OK(err, "skel_load"))
+ goto cleanup;
+ skel->bss->target_pid = getpid();
+ err = iters_task__attach(skel);
+ if (!ASSERT_OK(err, "iters_task__attach"))
+ goto cleanup;
+
+ iters_task__detach(skel);
+ ASSERT_EQ(skel->bss->process_cnt, 1, "process_cnt");
+
+cleanup:
+ iters_task__destroy(skel);
+}
+
+static void subtest_css_task_iters(void)
+{
+ struct iters_task *skel;
+ int err, cg_fd, cg_id;
+ const char *cgrp_path = "/cg1";
+
+ err = setup_cgroup_environment();
+ if (!ASSERT_OK(err, "setup_cgroup_environment"))
+ goto cleanup;
+ cg_fd = create_and_get_cgroup(cgrp_path);
+ if (!ASSERT_GE(cg_fd, 0, "cg_create"))
+ goto cleanup;
+ cg_id = get_cgroup_id(cgrp_path);
+ err = join_cgroup(cgrp_path);
+ if (!ASSERT_OK(err, "setup_cgroup_environment"))
+ goto cleanup;
+
+ skel = iters_task__open();
+ if (!ASSERT_OK_PTR(skel, "skel_open"))
+ goto cleanup;
+
+ bpf_program__set_autoload(skel->progs.iter_css_task_for_each, true);
+ err = iters_task__load(skel);
+ if (!ASSERT_OK(err, "skel_load"))
+ goto cleanup;
+
+ skel->bss->target_pid = getpid();
+ skel->bss->cg_id = cg_id;
+ err = iters_task__attach(skel);
+
+ if (!ASSERT_OK(err, "iters_task__attach"))
+ goto cleanup;
+
+ iters_task__detach(skel);
+ ASSERT_EQ(skel->bss->css_task_cnt, 1, "css_task_cnt");
+
+cleanup:
+ cleanup_cgroup_environment();
+ iters_task__destroy(skel);
+}
+
+static void subtest_css_dec_iters(void)
+{
+ struct iters_task *skel;
+ struct {
+ const char *path;
+ int fd;
+ } cgs[] = {
+ { "/cg1" },
+ { "/cg1/cg2" },
+ { "/cg1/cg2/cg3" },
+ { "/cg1/cg2/cg3/cg4" },
+ };
+ int err, cg_nr = ARRAY_SIZE(cgs);
+ int i;
+
+ err = setup_cgroup_environment();
+ if (!ASSERT_OK(err, "setup_cgroup_environment"))
+ goto cleanup;
+ for (i = 0; i < cg_nr; i++) {
+ cgs[i].fd = create_and_get_cgroup(cgs[i].path);
+ if (!ASSERT_GE(cgs[i].fd, 0, "cg_create"))
+ goto cleanup;
+ }
+
+ skel = iters_task__open();
+ if (!ASSERT_OK_PTR(skel, "skel_open"))
+ goto cleanup;
+ bpf_program__set_autoload(skel->progs.iter_css_dec_for_each, true);
+ err = iters_task__load(skel);
+ if (!ASSERT_OK(err, "skel_load"))
+ goto cleanup;
+
+ skel->bss->target_pid = getpid();
+ skel->bss->cg_id = get_cgroup_id(cgs[0].path);
+
+ err = iters_task__attach(skel);
+
+ if (!ASSERT_OK(err, "iters_task__attach"))
+ goto cleanup;
+
+ iters_task__detach(skel);
+ ASSERT_EQ(skel->bss->css_dec_cnt, cg_nr, "post order search dec count");
+ ASSERT_EQ(skel->bss->last_cg_id, get_cgroup_id(cgs[0].path),
+ "post order search last cgroup id");
+
+cleanup:
+ cleanup_cgroup_environment();
+ iters_task__destroy(skel);
+}
+
void test_iters(void)
{
RUN_TESTS(iters_state_safety);
@@ -103,4 +220,10 @@ void test_iters(void)
subtest_num_iters();
if (test__start_subtest("testmod_seq"))
subtest_testmod_seq_iters();
+ if (test__start_subtest("process"))
+ subtest_process_iters();
+ if (test__start_subtest("css_task"))
+ subtest_css_task_iters();
+ if (test__start_subtest("css_dec"))
+ subtest_css_dec_iters();
}
diff --git a/tools/testing/selftests/bpf/progs/iters_task.c b/tools/testing/selftests/bpf/progs/iters_task.c
new file mode 100644
index 000000000000..524926b505b0
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/iters_task.c
@@ -0,0 +1,83 @@
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+char _license[] SEC("license") = "GPL";
+
+pid_t target_pid = 0;
+int process_cnt = 0;
+int css_task_cnt = 0;
+int css_dec_cnt = 0;
+
+u64 cg_id;
+u64 last_cg_id;
+
+struct cgroup *bpf_cgroup_from_id(u64 cgid) __ksym;
+struct cgroup *bpf_cgroup_acquire(struct cgroup *cgrp) __ksym;
+void bpf_cgroup_release(struct cgroup *p) __ksym;
+
+SEC("?tp_btf/sys_enter")
+int BPF_PROG(iter_task_for_each)
+{
+ struct task_struct *task;
+ struct task_struct *cur_task = bpf_get_current_task_btf();
+
+ if (cur_task->pid != target_pid)
+ return 0;
+
+ bpf_for_each(process, task)
+ if (task->pid == target_pid)
+ process_cnt += 1;
+
+ return 0;
+}
+
+SEC("?tp_btf/sys_enter")
+int iter_css_task_for_each(const void *ctx)
+{
+ struct task_struct *task;
+ struct task_struct *cur_task = bpf_get_current_task_btf();
+
+ if (cur_task->pid != target_pid)
+ return 0;
+
+ struct cgroup *cgrp = bpf_cgroup_from_id(cg_id);
+
+ if (cgrp == NULL)
+ return 0;
+ struct cgroup_subsys_state *css = &cgrp->self;
+
+ bpf_for_each(css_task, task, css, 0)
+ if (task->pid == target_pid)
+ css_task_cnt += 1;
+
+ bpf_cgroup_release(cgrp);
+ return 0;
+}
+
+SEC("?tp_btf/sys_enter")
+int iter_css_dec_for_each(const void *ctx)
+{
+ struct task_struct *cur_task = bpf_get_current_task_btf();
+ bool is_post_order = true;
+
+ if (cur_task->pid != target_pid)
+ return 0;
+
+ struct cgroup *cgrp = bpf_cgroup_from_id(cg_id);
+
+ if (cgrp == NULL)
+ return 0;
+ struct cgroup_subsys_state *root = &cgrp->self;
+ struct cgroup_subsys_state *pos = NULL;
+
+ bpf_for_each(css, pos, root, is_post_order) {
+ struct cgroup *cur_cgrp = pos->cgroup;
+
+ css_dec_cnt += 1;
+ if (cur_cgrp)
+ last_cg_id = cur_cgrp->kn->id;
+ }
+ bpf_cgroup_release(cgrp);
+ return 0;
+}
--
2.20.1
