Re: [PATCH bpf-next v5 8/8] selftests/bpf: Add tests for open-coded task and css iter
From: Chuyi Zhou
Date: Wed Oct 11 2023 - 22:39:54 EST
在 2023/10/11 20:08, Chuyi Zhou 写道:
This patch adds three subtests to demonstrate these patterns and validating
correctness.
subtest1:
1) We use task_iter to iterate all process in the system and search for the
current process with a given pid.
2) We create some threads in current process context, and use
BPF_TASK_ITER_PROC_THREADS to iterate all threads of current process. As
expected, we would find all the threads of current process.
3) We create some threads and use BPF_TASK_ITER_ALL_THREADS to iterate all
threads in the system. As expected, we would find all the threads which was
created.
subtest2: We create a cgroup and add the current task 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.
subtest3:
1) We create a cgroup tree. In the BPF program, we use
bpf_for_each(css, pos, root, XXX) to iterate all descendant under the root
with pre and post order. As expected, we would find all descendant and the
last iterating cgroup in post-order is root cgroup, the first iterating
cgroup in pre-order is root cgroup.
2) We wse BPF_CGROUP_ITER_ANCESTORS_UP to traverse the cgroup tree starting
from leaf and root separately, and record the height. The diff of the
hights would be the total tree-high - 1.
Signed-off-by: Chuyi Zhou <zhouchuyi@xxxxxxxxxxxxx>
---
.../testing/selftests/bpf/prog_tests/iters.c | 161 ++++++++++++++++++
tools/testing/selftests/bpf/progs/iters_css.c | 74 ++++++++
.../selftests/bpf/progs/iters_css_task.c | 42 +++++
.../testing/selftests/bpf/progs/iters_task.c | 41 +++++
.../selftests/bpf/progs/iters_task_failure.c | 105 ++++++++++++
5 files changed, 423 insertions(+)
create mode 100644 tools/testing/selftests/bpf/progs/iters_css.c
create mode 100644 tools/testing/selftests/bpf/progs/iters_css_task.c
create mode 100644 tools/testing/selftests/bpf/progs/iters_task.c
create mode 100644 tools/testing/selftests/bpf/progs/iters_task_failure.c
diff --git a/tools/testing/selftests/bpf/prog_tests/iters.c b/tools/testing/selftests/bpf/prog_tests/iters.c
index 10804ae5ae97..8d7a7bef5c73 100644
--- a/tools/testing/selftests/bpf/prog_tests/iters.c
+++ b/tools/testing/selftests/bpf/prog_tests/iters.c
@@ -1,13 +1,24 @@
// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
+#include <sys/syscall.h>
+#include <sys/mman.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include <malloc.h>
+#include <stdlib.h>
#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"
+#include "iters_css_task.skel.h"
+#include "iters_css.skel.h"
+#include "iters_task_failure.skel.h"
static void subtest_num_iters(void)
{
@@ -90,6 +101,149 @@ static void subtest_testmod_seq_iters(void)
iters_testmod_seq__destroy(skel);
}
+static pthread_mutex_t do_nothing_mutex;
+
+static void *do_nothing_wait(void *arg)
+{
+ pthread_mutex_lock(&do_nothing_mutex);
+ pthread_mutex_unlock(&do_nothing_mutex);
+
+ pthread_exit(arg);
+}
+
+#define thread_num 2
+
+static void subtest_task_iters(void)
+{
+ struct iters_task *skel = NULL;
+ pthread_t thread_ids[thread_num];
+ void *ret;
+ int err;
+
+ skel = iters_task__open();
+ if (!ASSERT_OK_PTR(skel, "skel_open"))
+ goto cleanup;
+ 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;
+ pthread_mutex_lock(&do_nothing_mutex);
+ for (int i = 0; i < thread_num; i++)
+ ASSERT_OK(pthread_create(&thread_ids[i], NULL, &do_nothing_wait, NULL),
+ "pthread_create");
+
+ syscall(SYS_getpgid);
+ iters_task__detach(skel);
+ ASSERT_EQ(skel->bss->process_cnt, 1, "process_cnt");
+ ASSERT_EQ(skel->bss->thread_cnt, thread_num + 1, "thread_cnt");
+ ASSERT_EQ(skel->bss->all_thread_cnt, thread_num + 1, "all_thread_cnt");
+ pthread_mutex_unlock(&do_nothing_mutex);
+ for (int i = 0; i < thread_num; i++)
+ pthread_join(thread_ids[i], &ret);
+cleanup:
+ iters_task__destroy(skel);
+}
+
+extern int stack_mprotect(void);
+
+static void subtest_css_task_iters(void)
+{
+ struct iters_css_task *skel = NULL;
+ 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_css_task__open();
+ if (!ASSERT_OK_PTR(skel, "skel_open"))
+ goto cleanup;
+
+ err = iters_css_task__load(skel);
+ if (!ASSERT_OK(err, "skel_load"))
+ goto cleanup;
+
+ skel->bss->target_pid = getpid();
+ skel->bss->cg_id = cg_id;
+ err = iters_css_task__attach(skel);
+
+ err = stack_mprotect();
+ if (!ASSERT_OK(err, "iters_task__attach"))
+ goto cleanup;
The is incorrect and would fail the lsm_test in prog_test.
Here we should check the stack_mprotect return value is -1 or
-EPERM. In BPF Prog iter_css_task_for_each, we need to return -EPERM.
The whole logic should keep same with lsm_test.c/bpf_cookie.c
After the following fix, CI would works well.
(https://github.com/kernel-patches/bpf/actions/runs/6484774470/job/17609349165?pr=5808)
@@ -177,11 +177,12 @@ static void subtest_css_task_iters(void)
skel->bss->target_pid = getpid();
skel->bss->cg_id = cg_id;
err = iters_css_task__attach(skel);
-
- err = stack_mprotect();
if (!ASSERT_OK(err, "iters_task__attach"))
goto cleanup;
-
+ err = stack_mprotect();
+ if (!ASSERT_EQ(err, -1, "stack_mprotect") ||
+ !ASSERT_EQ(errno, EPERM, "stack_mprotect"))
+ goto cleanup;
iters_css_task__detach(skel);
ASSERT_EQ(skel->bss->css_task_cnt, 1, "css_task_cnt");
diff --git a/tools/testing/selftests/bpf/progs/iters_css_task.c
b/tools/testing/selftests/bpf/progs/iters_css_task.c
index 506a2755234e..9f79a57fde8e 100644
--- a/tools/testing/selftests/bpf/progs/iters_css_task.c
+++ b/tools/testing/selftests/bpf/progs/iters_css_task.c
@@ -2,6 +2,7 @@
/* Copyright (C) 2023 Chuyi Zhou <zhouchuyi@xxxxxxxxxxxxx> */
#include "vmlinux.h"
+#include <errno.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
#include "bpf_misc.h"
@@ -17,7 +18,8 @@ int css_task_cnt = 0;
u64 cg_id;
SEC("lsm/file_mprotect")
-int BPF_PROG(iter_css_task_for_each)
+int BPF_PROG(iter_css_task_for_each, struct vm_area_struct *vma,
+ unsigned long reqprot, unsigned long prot, int ret)
{
struct task_struct *cur_task = bpf_get_current_task_btf();
struct cgroup_subsys_state *css;
@@ -25,12 +27,12 @@ int BPF_PROG(iter_css_task_for_each)
struct cgroup *cgrp;
if (cur_task->pid != target_pid)
- return 0;
+ return ret;
cgrp = bpf_cgroup_from_id(cg_id);
- if (cgrp == NULL)
- return 0;
+ if (!cgrp)
+ goto out;
css = &cgrp->self;
bpf_for_each(css_task, task, css, CSS_TASK_ITER_PROCS)
@@ -38,5 +40,6 @@ int BPF_PROG(iter_css_task_for_each)
css_task_cnt += 1;
bpf_cgroup_release(cgrp);
- return 0;
+out:
+ return -EPERM;
}