[PATCH bpf-next v2 5/6] selftests/bpf: Add selftests for cgroup local storage

[Yonghong Song <yhs@fb.com>]

Add two tests for cgroup local storage, one to test bpf program helpers
and user space map APIs, and the other to test recursive fentry
triggering won't deadlock.

Signed-off-by: Yonghong Song <yhs@fb.com>
---
 .../bpf/prog_tests/cgroup_local_storage.c     | 92 +++++++++++++++++++
 .../bpf/progs/cgroup_local_storage.c          | 88 ++++++++++++++++++
 .../selftests/bpf/progs/cgroup_ls_recursion.c | 70 ++++++++++++++
 3 files changed, 250 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/cgroup_local_storage.c
 create mode 100644 tools/testing/selftests/bpf/progs/cgroup_local_storage.c
 create mode 100644 tools/testing/selftests/bpf/progs/cgroup_ls_recursion.c

diff --git a/tools/testing/selftests/bpf/prog_tests/cgroup_local_storage.c b/tools/testing/selftests/bpf/prog_tests/cgroup_local_storage.c
new file mode 100644
index 000000000000..69b1abda0d42
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/cgroup_local_storage.c
@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates.*/
+
+#define _GNU_SOURCE
+#include <unistd.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <test_progs.h>
+#include "cgroup_local_storage.skel.h"
+#include "cgroup_ls_recursion.skel.h"
+
+static void test_sys_enter_exit(int cgroup_fd)
+{
+	struct cgroup_local_storage *skel;
+	long val1 = 1, val2 = 0;
+	int err;
+
+	skel = cgroup_local_storage__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "skel_open_and_load"))
+		return;
+
+	/* populate a value in cgrp_storage_2 */
+	err = bpf_map_update_elem(bpf_map__fd(skel->maps.cgrp_storage_2), &cgroup_fd, &val1, BPF_ANY);
+	if (!ASSERT_OK(err, "map_update_elem"))
+		goto out;
+
+	/* check value */
+	err = bpf_map_lookup_elem(bpf_map__fd(skel->maps.cgrp_storage_2), &cgroup_fd, &val2);
+	if (!ASSERT_OK(err, "map_lookup_elem"))
+		goto out;
+	if (!ASSERT_EQ(val2, 1, "map_lookup_elem, invalid val"))
+		goto out;
+
+	/* delete value */
+	err = bpf_map_delete_elem(bpf_map__fd(skel->maps.cgrp_storage_2), &cgroup_fd);
+	if (!ASSERT_OK(err, "map_delete_elem"))
+		goto out;
+
+	skel->bss->target_pid = syscall(SYS_gettid);
+
+	err = cgroup_local_storage__attach(skel);
+	if (!ASSERT_OK(err, "skel_attach"))
+		goto out;
+
+	syscall(SYS_gettid);
+	syscall(SYS_gettid);
+
+	skel->bss->target_pid = 0;
+
+	/* 3x syscalls: 1x attach and 2x gettid */
+	ASSERT_EQ(skel->bss->enter_cnt, 3, "enter_cnt");
+	ASSERT_EQ(skel->bss->exit_cnt, 3, "exit_cnt");
+	ASSERT_EQ(skel->bss->mismatch_cnt, 0, "mismatch_cnt");
+out:
+	cgroup_local_storage__destroy(skel);
+}
+
+static void test_recursion(int cgroup_fd)
+{
+	struct cgroup_ls_recursion *skel;
+	int err;
+
+	skel = cgroup_ls_recursion__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "skel_open_and_load"))
+		return;
+
+	err = cgroup_ls_recursion__attach(skel);
+	if (!ASSERT_OK(err, "skel_attach"))
+		goto out;
+
+	/* trigger sys_enter, make sure it does not cause deadlock */
+	syscall(SYS_gettid);
+
+out:
+	cgroup_ls_recursion__destroy(skel);
+}
+
+void test_cgroup_local_storage(void)
+{
+	int cgroup_fd;
+
+	cgroup_fd = test__join_cgroup("/cgroup_local_storage");
+	if (!ASSERT_GE(cgroup_fd, 0, "join_cgroup /cgroup_local_storage"))
+		return;
+
+	if (test__start_subtest("sys_enter_exit"))
+		test_sys_enter_exit(cgroup_fd);
+	if (test__start_subtest("recursion"))
+		test_recursion(cgroup_fd);
+
+	close(cgroup_fd);
+}
diff --git a/tools/testing/selftests/bpf/progs/cgroup_local_storage.c b/tools/testing/selftests/bpf/progs/cgroup_local_storage.c
new file mode 100644
index 000000000000..dee63d4c1512
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/cgroup_local_storage.c
@@ -0,0 +1,88 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+char _license[] SEC("license") = "GPL";
+
+struct {
+	__uint(type, BPF_MAP_TYPE_CGRP_STORAGE);
+	__uint(map_flags, BPF_F_NO_PREALLOC);
+	__type(key, int);
+	__type(value, long);
+} cgrp_storage_1 SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_CGRP_STORAGE);
+	__uint(map_flags, BPF_F_NO_PREALLOC);
+	__type(key, int);
+	__type(value, long);
+} cgrp_storage_2 SEC(".maps");
+
+#define MAGIC_VALUE 0xabcd1234
+
+pid_t target_pid = 0;
+int mismatch_cnt = 0;
+int enter_cnt = 0;
+int exit_cnt = 0;
+
+SEC("tp_btf/sys_enter")
+int BPF_PROG(on_enter, struct pt_regs *regs, long id)
+{
+	struct task_struct *task;
+	long *ptr;
+	int err;
+
+	task = bpf_get_current_task_btf();
+	if (task->pid != target_pid)
+		return 0;
+
+	/* populate value 0 */
+	ptr = bpf_cgrp_storage_get(&cgrp_storage_1, task->cgroups->dfl_cgrp, 0,
+				   BPF_LOCAL_STORAGE_GET_F_CREATE);
+	if (!ptr)
+		return 0;
+
+	/* delete value 0 */
+	err = bpf_cgrp_storage_delete(&cgrp_storage_1, task->cgroups->dfl_cgrp);
+	if (err)
+		return 0;
+
+	/* value is not available */
+	ptr = bpf_cgrp_storage_get(&cgrp_storage_1, task->cgroups->dfl_cgrp, 0, 0);
+	if (ptr)
+		return 0;
+
+	/* re-populate the value */
+	ptr = bpf_cgrp_storage_get(&cgrp_storage_1, task->cgroups->dfl_cgrp, 0,
+				   BPF_LOCAL_STORAGE_GET_F_CREATE);
+	if (!ptr)
+		return 0;
+	__sync_fetch_and_add(&enter_cnt, 1);
+	*ptr = MAGIC_VALUE + enter_cnt;
+
+	return 0;
+}
+
+SEC("tp_btf/sys_exit")
+int BPF_PROG(on_exit, struct pt_regs *regs, long id)
+{
+	struct task_struct *task;
+	long *ptr;
+
+	task = bpf_get_current_task_btf();
+	if (task->pid != target_pid)
+		return 0;
+
+	ptr = bpf_cgrp_storage_get(&cgrp_storage_1, task->cgroups->dfl_cgrp, 0,
+				   BPF_LOCAL_STORAGE_GET_F_CREATE);
+	if (!ptr)
+		return 0;
+
+	__sync_fetch_and_add(&exit_cnt, 1);
+	if (*ptr != MAGIC_VALUE + exit_cnt)
+		__sync_fetch_and_add(&mismatch_cnt, 1);
+	return 0;
+}
diff --git a/tools/testing/selftests/bpf/progs/cgroup_ls_recursion.c b/tools/testing/selftests/bpf/progs/cgroup_ls_recursion.c
new file mode 100644
index 000000000000..a043d8fefdac
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/cgroup_ls_recursion.c
@@ -0,0 +1,70 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+char _license[] SEC("license") = "GPL";
+
+struct {
+	__uint(type, BPF_MAP_TYPE_CGRP_STORAGE);
+	__uint(map_flags, BPF_F_NO_PREALLOC);
+	__type(key, int);
+	__type(value, long);
+} map_a SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_CGRP_STORAGE);
+	__uint(map_flags, BPF_F_NO_PREALLOC);
+	__type(key, int);
+	__type(value, long);
+} map_b SEC(".maps");
+
+SEC("fentry/bpf_local_storage_lookup")
+int BPF_PROG(on_lookup)
+{
+	struct task_struct *task = bpf_get_current_task_btf();
+
+	bpf_cgrp_storage_delete(&map_a, task->cgroups->dfl_cgrp);
+	bpf_cgrp_storage_delete(&map_b, task->cgroups->dfl_cgrp);
+	return 0;
+}
+
+SEC("fentry/bpf_local_storage_update")
+int BPF_PROG(on_update)
+{
+	struct task_struct *task = bpf_get_current_task_btf();
+	long *ptr;
+
+	ptr = bpf_cgrp_storage_get(&map_a, task->cgroups->dfl_cgrp, 0,
+				   BPF_LOCAL_STORAGE_GET_F_CREATE);
+	if (ptr)
+		*ptr += 1;
+
+	ptr = bpf_cgrp_storage_get(&map_b, task->cgroups->dfl_cgrp, 0,
+				   BPF_LOCAL_STORAGE_GET_F_CREATE);
+	if (ptr)
+		*ptr += 1;
+
+	return 0;
+}
+
+SEC("tp_btf/sys_enter")
+int BPF_PROG(on_enter, struct pt_regs *regs, long id)
+{
+	struct task_struct *task;
+	long *ptr;
+
+	task = bpf_get_current_task_btf();
+	ptr = bpf_cgrp_storage_get(&map_a, task->cgroups->dfl_cgrp, 0,
+				   BPF_LOCAL_STORAGE_GET_F_CREATE);
+	if (ptr)
+		*ptr = 200;
+
+	ptr = bpf_cgrp_storage_get(&map_b, task->cgroups->dfl_cgrp, 0,
+				   BPF_LOCAL_STORAGE_GET_F_CREATE);
+	if (ptr)
+		*ptr = 100;
+	return 0;
+}
-- 
2.30.2