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authorChuyi Zhou2023-10-31 13:04:37 +0800
committerAlexei Starovoitov2023-11-01 22:49:20 -0700
commitf49843afde6771ef6ed5d021eacafacfc98a58bf (patch)
tree0cb994bfda2cbc5b435bff4513c41ae622264af2 /tools
parent3091b667498b0a212e760e1033e5f9b8c33a948f (diff)
selftests/bpf: Add tests for css_task iter combining with cgroup iter
This patch adds a test which demonstrates how css_task iter can be combined with cgroup iter and it won't cause deadlock, though cgroup iter is not sleepable. Signed-off-by: Chuyi Zhou <zhouchuyi@bytedance.com> Acked-by: Yonghong Song <yonghong.song@linux.dev> Link: https://lore.kernel.org/r/20231031050438.93297-3-zhouchuyi@bytedance.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'tools')
-rw-r--r--tools/testing/selftests/bpf/prog_tests/cgroup_iter.c33
-rw-r--r--tools/testing/selftests/bpf/progs/iters_css_task.c44
2 files changed, 77 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/cgroup_iter.c b/tools/testing/selftests/bpf/prog_tests/cgroup_iter.c
index e02feb5fae97..574d9a0cdc8e 100644
--- a/tools/testing/selftests/bpf/prog_tests/cgroup_iter.c
+++ b/tools/testing/selftests/bpf/prog_tests/cgroup_iter.c
@@ -4,6 +4,7 @@
#include <test_progs.h>
#include <bpf/libbpf.h>
#include <bpf/btf.h>
+#include "iters_css_task.skel.h"
#include "cgroup_iter.skel.h"
#include "cgroup_helpers.h"
@@ -263,6 +264,35 @@ close_cgrp:
close(cgrp_fd);
}
+static void test_walk_self_only_css_task(void)
+{
+ struct iters_css_task *skel;
+ int err;
+
+ skel = iters_css_task__open();
+ if (!ASSERT_OK_PTR(skel, "skel_open"))
+ return;
+
+ bpf_program__set_autoload(skel->progs.cgroup_id_printer, true);
+
+ err = iters_css_task__load(skel);
+ if (!ASSERT_OK(err, "skel_load"))
+ goto cleanup;
+
+ err = join_cgroup(cg_path[CHILD2]);
+ if (!ASSERT_OK(err, "join_cgroup"))
+ goto cleanup;
+
+ skel->bss->target_pid = getpid();
+ snprintf(expected_output, sizeof(expected_output),
+ PROLOGUE "%8llu\n" EPILOGUE, cg_id[CHILD2]);
+ read_from_cgroup_iter(skel->progs.cgroup_id_printer, cg_fd[CHILD2],
+ BPF_CGROUP_ITER_SELF_ONLY, "test_walk_self_only_css_task");
+ ASSERT_EQ(skel->bss->css_task_cnt, 1, "css_task_cnt");
+cleanup:
+ iters_css_task__destroy(skel);
+}
+
void test_cgroup_iter(void)
{
struct cgroup_iter *skel = NULL;
@@ -293,6 +323,9 @@ void test_cgroup_iter(void)
test_walk_self_only(skel);
if (test__start_subtest("cgroup_iter__dead_self_only"))
test_walk_dead_self_only(skel);
+ if (test__start_subtest("cgroup_iter__self_only_css_task"))
+ test_walk_self_only_css_task();
+
out:
cgroup_iter__destroy(skel);
cleanup_cgroups();
diff --git a/tools/testing/selftests/bpf/progs/iters_css_task.c b/tools/testing/selftests/bpf/progs/iters_css_task.c
index 5089ce384a1c..384ff806990f 100644
--- a/tools/testing/selftests/bpf/progs/iters_css_task.c
+++ b/tools/testing/selftests/bpf/progs/iters_css_task.c
@@ -10,6 +10,7 @@
char _license[] SEC("license") = "GPL";
+struct cgroup *bpf_cgroup_acquire(struct cgroup *p) __ksym;
struct cgroup *bpf_cgroup_from_id(u64 cgid) __ksym;
void bpf_cgroup_release(struct cgroup *p) __ksym;
@@ -45,3 +46,46 @@ int BPF_PROG(iter_css_task_for_each, struct vm_area_struct *vma,
return -EPERM;
}
+
+static inline u64 cgroup_id(struct cgroup *cgrp)
+{
+ return cgrp->kn->id;
+}
+
+SEC("?iter/cgroup")
+int cgroup_id_printer(struct bpf_iter__cgroup *ctx)
+{
+ struct seq_file *seq = ctx->meta->seq;
+ struct cgroup *cgrp, *acquired;
+ struct cgroup_subsys_state *css;
+ struct task_struct *task;
+ u64 cgrp_id;
+
+ cgrp = ctx->cgroup;
+
+ /* epilogue */
+ if (cgrp == NULL) {
+ BPF_SEQ_PRINTF(seq, "epilogue\n");
+ return 0;
+ }
+
+ /* prologue */
+ if (ctx->meta->seq_num == 0)
+ BPF_SEQ_PRINTF(seq, "prologue\n");
+
+ cgrp_id = cgroup_id(cgrp);
+
+ BPF_SEQ_PRINTF(seq, "%8llu\n", cgrp_id);
+
+ acquired = bpf_cgroup_from_id(cgrp_id);
+ if (!acquired)
+ return 0;
+ css = &acquired->self;
+ css_task_cnt = 0;
+ bpf_for_each(css_task, task, css, CSS_TASK_ITER_PROCS) {
+ if (task->pid == target_pid)
+ css_task_cnt++;
+ }
+ bpf_cgroup_release(acquired);
+ return 0;
+}