On Sat, Apr 22, 2023 at 8:51 PM Feng Zhou zhoufeng.zf@bytedance.com wrote:

在 2023/4/22 02:24, Alexei Starovoitov 写道:

On Fri, Apr 21, 2023 at 05:04:03PM +0800, Feng zhou wrote:

From: Feng Zhou zhoufeng.zf@bytedance.com

test_progs: Tests new kfunc bpf_task_under_cgroup().

The bpf program saves the pid which call the getuid syscall within a given cgroup to the remote_pid, which is convenient for the user-mode program to verify the test correctness.

The user-mode program creates its own mount namespace, and mounts the cgroupsv2 hierarchy in there, call the getuid syscall, then check if remote_pid and local_pid are equal.

Signed-off-by: Feng Zhou zhoufeng.zf@bytedance.com

.../bpf/prog_tests/task_under_cgroup.c | 46 +++++++++++++++++++ .../selftests/bpf/progs/cgrp_kfunc_common.h | 1 + .../bpf/progs/test_task_under_cgroup.c | 40 ++++++++++++++++ 3 files changed, 87 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/task_under_cgroup.c create mode 100644 tools/testing/selftests/bpf/progs/test_task_under_cgroup.c

diff --git a/tools/testing/selftests/bpf/prog_tests/task_under_cgroup.c b/tools/testing/selftests/bpf/prog_tests/task_under_cgroup.c new file mode 100644 index 000000000000..bd3deb469938 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/task_under_cgroup.c @@ -0,0 +1,46 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2023 Bytedance */

+#include <test_progs.h> +#include <cgroup_helpers.h> +#include "test_task_under_cgroup.skel.h"

+#define FOO "/foo"

+void test_task_under_cgroup(void) +{

• struct test_task_under_cgroup *skel;
• int ret, foo = -1;
• foo = test__join_cgroup(FOO);
• if (!ASSERT_OK(foo < 0, "cgroup_join_foo"))
• return;
• skel = test_task_under_cgroup__open();
• if (!ASSERT_OK_PTR(skel, "test_task_under_cgroup__open"))
• goto cleanup;
• skel->rodata->local_pid = getpid();
• skel->rodata->cgid = get_cgroup_id(FOO);
• ret = test_task_under_cgroup__load(skel);
• if (!ASSERT_OK(ret, "test_task_under_cgroup__load"))
• goto cleanup;
• ret = test_task_under_cgroup__attach(skel);
• if (!ASSERT_OK(ret, "test_task_under_cgroup__attach"))
• goto cleanup;
• syscall(__NR_getuid);
• test_task_under_cgroup__detach(skel);
• ASSERT_EQ(skel->bss->remote_pid, skel->rodata->local_pid,
• "test task_under_cgroup");

+cleanup:

• if (foo)
• close(foo);

Looks wrong. should be if (foo >= 0) ?

Yes.

• test_task_under_cgroup__destroy(skel);

+} diff --git a/tools/testing/selftests/bpf/progs/cgrp_kfunc_common.h b/tools/testing/selftests/bpf/progs/cgrp_kfunc_common.h index 22914a70db54..41b3ea231698 100644 --- a/tools/testing/selftests/bpf/progs/cgrp_kfunc_common.h +++ b/tools/testing/selftests/bpf/progs/cgrp_kfunc_common.h @@ -26,6 +26,7 @@ struct cgroup *bpf_cgroup_ancestor(struct cgroup *cgrp, int level) __ksym; struct cgroup *bpf_cgroup_from_id(u64 cgid) __ksym; void bpf_rcu_read_lock(void) __ksym; void bpf_rcu_read_unlock(void) __ksym; +int bpf_task_under_cgroup(struct cgroup *cgrp, struct task_struct *task) __ksym;

static inline struct __cgrps_kfunc_map_value *cgrps_kfunc_map_value_lookup(struct cgroup *cgrp) { diff --git a/tools/testing/selftests/bpf/progs/test_task_under_cgroup.c b/tools/testing/selftests/bpf/progs/test_task_under_cgroup.c new file mode 100644 index 000000000000..e2740f9b029d --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_task_under_cgroup.c @@ -0,0 +1,40 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2023 Bytedance */

+#include <vmlinux.h> +#include <asm/unistd.h> +#include <bpf/bpf_tracing.h> +#include <bpf/bpf_helpers.h>

+#include "cgrp_kfunc_common.h"

+const volatile int local_pid; +const volatile long cgid; +int remote_pid;

+SEC("tp_btf/sys_enter")

pls narrow down to specific syscall. Like you use in user space part: getuid

Also add this test to denylist.s390. See BPF CI failure.

bpf_task_under_cgroup is placed in generic_btf_ids, belongs to BPF_PROG_TYPE_TRACING,

if narrow down to specific syscall and uses SEC ("tp/syscalls/sys_enter_getuid"),

bpf prog type is TRACEPOINT, kfunc cannot be used, and reports

"calls kernel function bpf_cgroup_from_id is not allowed".

sure, pls narrow it down. sys_enter is too broad. In parallel test_progs the bpf prog will be way too many times.