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selftests/bpf: Add tests for open-coded task and css iter
This patch adds 4 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. subtest4: Add some failure testcase when using css_task, task and css iters, e.g, unlock when using task-iters to iterate tasks. Signed-off-by: Chuyi Zhou <zhouchuyi@bytedance.com> Link: https://lore.kernel.org/r/20231018061746.111364-9-zhouchuyi@bytedance.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
parent
ddab78cbb5
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5 changed files with 415 additions and 0 deletions
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@ -1,7 +1,14 @@
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// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
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#include <sys/syscall.h>
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#include <sys/mman.h>
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#include <sys/wait.h>
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#include <unistd.h>
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#include <malloc.h>
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#include <stdlib.h>
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#include <test_progs.h>
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#include "cgroup_helpers.h"
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#include "iters.skel.h"
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#include "iters_state_safety.skel.h"
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@ -9,6 +16,10 @@
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#include "iters_num.skel.h"
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#include "iters_testmod_seq.skel.h"
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#include "iters_task_vma.skel.h"
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#include "iters_task.skel.h"
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#include "iters_css_task.skel.h"
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#include "iters_css.skel.h"
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#include "iters_task_failure.skel.h"
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static void subtest_num_iters(void)
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{
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@ -146,6 +157,138 @@ static void subtest_task_vma_iters(void)
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iters_task_vma__destroy(skel);
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}
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static pthread_mutex_t do_nothing_mutex;
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static void *do_nothing_wait(void *arg)
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{
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pthread_mutex_lock(&do_nothing_mutex);
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pthread_mutex_unlock(&do_nothing_mutex);
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pthread_exit(arg);
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}
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#define thread_num 2
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static void subtest_task_iters(void)
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{
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struct iters_task *skel = NULL;
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pthread_t thread_ids[thread_num];
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void *ret;
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int err;
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skel = iters_task__open_and_load();
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if (!ASSERT_OK_PTR(skel, "open_and_load"))
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goto cleanup;
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skel->bss->target_pid = getpid();
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err = iters_task__attach(skel);
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if (!ASSERT_OK(err, "iters_task__attach"))
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goto cleanup;
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pthread_mutex_lock(&do_nothing_mutex);
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for (int i = 0; i < thread_num; i++)
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ASSERT_OK(pthread_create(&thread_ids[i], NULL, &do_nothing_wait, NULL),
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"pthread_create");
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syscall(SYS_getpgid);
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iters_task__detach(skel);
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ASSERT_EQ(skel->bss->procs_cnt, 1, "procs_cnt");
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ASSERT_EQ(skel->bss->threads_cnt, thread_num + 1, "threads_cnt");
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ASSERT_EQ(skel->bss->proc_threads_cnt, thread_num + 1, "proc_threads_cnt");
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pthread_mutex_unlock(&do_nothing_mutex);
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for (int i = 0; i < thread_num; i++)
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ASSERT_OK(pthread_join(thread_ids[i], &ret), "pthread_join");
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cleanup:
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iters_task__destroy(skel);
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}
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extern int stack_mprotect(void);
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static void subtest_css_task_iters(void)
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{
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struct iters_css_task *skel = NULL;
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int err, cg_fd, cg_id;
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const char *cgrp_path = "/cg1";
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err = setup_cgroup_environment();
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if (!ASSERT_OK(err, "setup_cgroup_environment"))
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goto cleanup;
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cg_fd = create_and_get_cgroup(cgrp_path);
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if (!ASSERT_GE(cg_fd, 0, "create_and_get_cgroup"))
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goto cleanup;
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cg_id = get_cgroup_id(cgrp_path);
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err = join_cgroup(cgrp_path);
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if (!ASSERT_OK(err, "join_cgroup"))
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goto cleanup;
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skel = iters_css_task__open_and_load();
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if (!ASSERT_OK_PTR(skel, "open_and_load"))
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goto cleanup;
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skel->bss->target_pid = getpid();
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skel->bss->cg_id = cg_id;
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err = iters_css_task__attach(skel);
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if (!ASSERT_OK(err, "iters_task__attach"))
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goto cleanup;
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err = stack_mprotect();
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if (!ASSERT_EQ(err, -1, "stack_mprotect") ||
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!ASSERT_EQ(errno, EPERM, "stack_mprotect"))
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goto cleanup;
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iters_css_task__detach(skel);
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ASSERT_EQ(skel->bss->css_task_cnt, 1, "css_task_cnt");
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cleanup:
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cleanup_cgroup_environment();
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iters_css_task__destroy(skel);
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}
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static void subtest_css_iters(void)
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{
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struct iters_css *skel = NULL;
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struct {
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const char *path;
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int fd;
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} cgs[] = {
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{ "/cg1" },
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{ "/cg1/cg2" },
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{ "/cg1/cg2/cg3" },
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{ "/cg1/cg2/cg3/cg4" },
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};
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int err, cg_nr = ARRAY_SIZE(cgs);
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int i;
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err = setup_cgroup_environment();
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if (!ASSERT_OK(err, "setup_cgroup_environment"))
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goto cleanup;
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for (i = 0; i < cg_nr; i++) {
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cgs[i].fd = create_and_get_cgroup(cgs[i].path);
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if (!ASSERT_GE(cgs[i].fd, 0, "create_and_get_cgroup"))
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goto cleanup;
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}
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skel = iters_css__open_and_load();
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if (!ASSERT_OK_PTR(skel, "open_and_load"))
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goto cleanup;
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skel->bss->target_pid = getpid();
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skel->bss->root_cg_id = get_cgroup_id(cgs[0].path);
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skel->bss->leaf_cg_id = get_cgroup_id(cgs[cg_nr - 1].path);
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err = iters_css__attach(skel);
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if (!ASSERT_OK(err, "iters_task__attach"))
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goto cleanup;
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syscall(SYS_getpgid);
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ASSERT_EQ(skel->bss->pre_order_cnt, cg_nr, "pre_order_cnt");
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ASSERT_EQ(skel->bss->first_cg_id, get_cgroup_id(cgs[0].path), "first_cg_id");
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ASSERT_EQ(skel->bss->post_order_cnt, cg_nr, "post_order_cnt");
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ASSERT_EQ(skel->bss->last_cg_id, get_cgroup_id(cgs[0].path), "last_cg_id");
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ASSERT_EQ(skel->bss->tree_high, cg_nr - 1, "tree_high");
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iters_css__detach(skel);
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cleanup:
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cleanup_cgroup_environment();
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iters_css__destroy(skel);
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}
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void test_iters(void)
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{
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RUN_TESTS(iters_state_safety);
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subtest_testmod_seq_iters();
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if (test__start_subtest("task_vma"))
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subtest_task_vma_iters();
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if (test__start_subtest("task"))
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subtest_task_iters();
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if (test__start_subtest("css_task"))
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subtest_css_task_iters();
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if (test__start_subtest("css"))
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subtest_css_iters();
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RUN_TESTS(iters_task_failure);
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}
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72
tools/testing/selftests/bpf/progs/iters_css.c
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72
tools/testing/selftests/bpf/progs/iters_css.c
Normal file
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// SPDX-License-Identifier: GPL-2.0
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/* Copyright (C) 2023 Chuyi Zhou <zhouchuyi@bytedance.com> */
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#include "vmlinux.h"
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_tracing.h>
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#include "bpf_misc.h"
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#include "bpf_experimental.h"
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char _license[] SEC("license") = "GPL";
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pid_t target_pid;
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u64 root_cg_id, leaf_cg_id;
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u64 first_cg_id, last_cg_id;
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int pre_order_cnt, post_order_cnt, tree_high;
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struct cgroup *bpf_cgroup_from_id(u64 cgid) __ksym;
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void bpf_cgroup_release(struct cgroup *p) __ksym;
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void bpf_rcu_read_lock(void) __ksym;
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void bpf_rcu_read_unlock(void) __ksym;
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SEC("fentry.s/" SYS_PREFIX "sys_getpgid")
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int iter_css_for_each(const void *ctx)
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{
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struct task_struct *cur_task = bpf_get_current_task_btf();
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struct cgroup_subsys_state *root_css, *leaf_css, *pos;
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struct cgroup *root_cgrp, *leaf_cgrp, *cur_cgrp;
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if (cur_task->pid != target_pid)
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return 0;
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root_cgrp = bpf_cgroup_from_id(root_cg_id);
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if (!root_cgrp)
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return 0;
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leaf_cgrp = bpf_cgroup_from_id(leaf_cg_id);
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if (!leaf_cgrp) {
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bpf_cgroup_release(root_cgrp);
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return 0;
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}
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root_css = &root_cgrp->self;
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leaf_css = &leaf_cgrp->self;
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pre_order_cnt = post_order_cnt = tree_high = 0;
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first_cg_id = last_cg_id = 0;
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bpf_rcu_read_lock();
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bpf_for_each(css, pos, root_css, BPF_CGROUP_ITER_DESCENDANTS_POST) {
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cur_cgrp = pos->cgroup;
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post_order_cnt++;
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last_cg_id = cur_cgrp->kn->id;
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}
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bpf_for_each(css, pos, root_css, BPF_CGROUP_ITER_DESCENDANTS_PRE) {
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cur_cgrp = pos->cgroup;
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pre_order_cnt++;
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if (!first_cg_id)
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first_cg_id = cur_cgrp->kn->id;
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}
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bpf_for_each(css, pos, leaf_css, BPF_CGROUP_ITER_ANCESTORS_UP)
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tree_high++;
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bpf_for_each(css, pos, root_css, BPF_CGROUP_ITER_ANCESTORS_UP)
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tree_high--;
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bpf_rcu_read_unlock();
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bpf_cgroup_release(root_cgrp);
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bpf_cgroup_release(leaf_cgrp);
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return 0;
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}
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47
tools/testing/selftests/bpf/progs/iters_css_task.c
Normal file
47
tools/testing/selftests/bpf/progs/iters_css_task.c
Normal file
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// SPDX-License-Identifier: GPL-2.0
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/* Copyright (C) 2023 Chuyi Zhou <zhouchuyi@bytedance.com> */
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#include "vmlinux.h"
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#include <errno.h>
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_tracing.h>
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#include "bpf_misc.h"
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#include "bpf_experimental.h"
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char _license[] SEC("license") = "GPL";
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struct cgroup *bpf_cgroup_from_id(u64 cgid) __ksym;
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void bpf_cgroup_release(struct cgroup *p) __ksym;
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pid_t target_pid;
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int css_task_cnt;
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u64 cg_id;
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SEC("lsm/file_mprotect")
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int BPF_PROG(iter_css_task_for_each, struct vm_area_struct *vma,
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unsigned long reqprot, unsigned long prot, int ret)
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{
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struct task_struct *cur_task = bpf_get_current_task_btf();
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struct cgroup_subsys_state *css;
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struct task_struct *task;
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struct cgroup *cgrp;
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if (cur_task->pid != target_pid)
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return ret;
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cgrp = bpf_cgroup_from_id(cg_id);
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if (!cgrp)
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return -EPERM;
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css = &cgrp->self;
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css_task_cnt = 0;
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bpf_for_each(css_task, task, css, CSS_TASK_ITER_PROCS)
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if (task->pid == target_pid)
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css_task_cnt++;
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bpf_cgroup_release(cgrp);
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return -EPERM;
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}
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41
tools/testing/selftests/bpf/progs/iters_task.c
Normal file
41
tools/testing/selftests/bpf/progs/iters_task.c
Normal file
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// SPDX-License-Identifier: GPL-2.0
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/* Copyright (C) 2023 Chuyi Zhou <zhouchuyi@bytedance.com> */
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#include "vmlinux.h"
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_tracing.h>
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#include "bpf_misc.h"
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#include "bpf_experimental.h"
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char _license[] SEC("license") = "GPL";
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pid_t target_pid;
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int procs_cnt, threads_cnt, proc_threads_cnt;
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void bpf_rcu_read_lock(void) __ksym;
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void bpf_rcu_read_unlock(void) __ksym;
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SEC("fentry.s/" SYS_PREFIX "sys_getpgid")
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int iter_task_for_each_sleep(void *ctx)
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{
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struct task_struct *cur_task = bpf_get_current_task_btf();
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struct task_struct *pos;
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if (cur_task->pid != target_pid)
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return 0;
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procs_cnt = threads_cnt = proc_threads_cnt = 0;
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bpf_rcu_read_lock();
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bpf_for_each(task, pos, NULL, BPF_TASK_ITER_ALL_PROCS)
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if (pos->pid == target_pid)
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procs_cnt++;
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bpf_for_each(task, pos, cur_task, BPF_TASK_ITER_PROC_THREADS)
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proc_threads_cnt++;
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bpf_for_each(task, pos, NULL, BPF_TASK_ITER_ALL_THREADS)
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if (pos->tgid == target_pid)
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threads_cnt++;
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bpf_rcu_read_unlock();
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return 0;
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}
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105
tools/testing/selftests/bpf/progs/iters_task_failure.c
Normal file
105
tools/testing/selftests/bpf/progs/iters_task_failure.c
Normal file
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// SPDX-License-Identifier: GPL-2.0
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/* Copyright (C) 2023 Chuyi Zhou <zhouchuyi@bytedance.com> */
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#include "vmlinux.h"
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_tracing.h>
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#include "bpf_misc.h"
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#include "bpf_experimental.h"
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char _license[] SEC("license") = "GPL";
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struct cgroup *bpf_cgroup_from_id(u64 cgid) __ksym;
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void bpf_cgroup_release(struct cgroup *p) __ksym;
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void bpf_rcu_read_lock(void) __ksym;
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void bpf_rcu_read_unlock(void) __ksym;
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SEC("?fentry.s/" SYS_PREFIX "sys_getpgid")
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__failure __msg("expected an RCU CS when using bpf_iter_task_next")
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int BPF_PROG(iter_tasks_without_lock)
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{
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struct task_struct *pos;
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bpf_for_each(task, pos, NULL, BPF_TASK_ITER_ALL_PROCS) {
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}
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return 0;
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}
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SEC("?fentry.s/" SYS_PREFIX "sys_getpgid")
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__failure __msg("expected an RCU CS when using bpf_iter_css_next")
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int BPF_PROG(iter_css_without_lock)
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{
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u64 cg_id = bpf_get_current_cgroup_id();
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struct cgroup *cgrp = bpf_cgroup_from_id(cg_id);
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struct cgroup_subsys_state *root_css, *pos;
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if (!cgrp)
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return 0;
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root_css = &cgrp->self;
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bpf_for_each(css, pos, root_css, BPF_CGROUP_ITER_DESCENDANTS_POST) {
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}
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bpf_cgroup_release(cgrp);
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return 0;
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}
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SEC("?fentry.s/" SYS_PREFIX "sys_getpgid")
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__failure __msg("expected an RCU CS when using bpf_iter_task_next")
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int BPF_PROG(iter_tasks_lock_and_unlock)
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{
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struct task_struct *pos;
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bpf_rcu_read_lock();
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bpf_for_each(task, pos, NULL, BPF_TASK_ITER_ALL_PROCS) {
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bpf_rcu_read_unlock();
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||||
bpf_rcu_read_lock();
|
||||
}
|
||||
bpf_rcu_read_unlock();
|
||||
return 0;
|
||||
}
|
||||
|
||||
SEC("?fentry.s/" SYS_PREFIX "sys_getpgid")
|
||||
__failure __msg("expected an RCU CS when using bpf_iter_css_next")
|
||||
int BPF_PROG(iter_css_lock_and_unlock)
|
||||
{
|
||||
u64 cg_id = bpf_get_current_cgroup_id();
|
||||
struct cgroup *cgrp = bpf_cgroup_from_id(cg_id);
|
||||
struct cgroup_subsys_state *root_css, *pos;
|
||||
|
||||
if (!cgrp)
|
||||
return 0;
|
||||
root_css = &cgrp->self;
|
||||
|
||||
bpf_rcu_read_lock();
|
||||
bpf_for_each(css, pos, root_css, BPF_CGROUP_ITER_DESCENDANTS_POST) {
|
||||
bpf_rcu_read_unlock();
|
||||
|
||||
bpf_rcu_read_lock();
|
||||
}
|
||||
bpf_rcu_read_unlock();
|
||||
bpf_cgroup_release(cgrp);
|
||||
return 0;
|
||||
}
|
||||
|
||||
SEC("?fentry.s/" SYS_PREFIX "sys_getpgid")
|
||||
__failure __msg("css_task_iter is only allowed in bpf_lsm and bpf iter-s")
|
||||
int BPF_PROG(iter_css_task_for_each)
|
||||
{
|
||||
u64 cg_id = bpf_get_current_cgroup_id();
|
||||
struct cgroup *cgrp = bpf_cgroup_from_id(cg_id);
|
||||
struct cgroup_subsys_state *css;
|
||||
struct task_struct *task;
|
||||
|
||||
if (cgrp == NULL)
|
||||
return 0;
|
||||
css = &cgrp->self;
|
||||
|
||||
bpf_for_each(css_task, task, css, CSS_TASK_ITER_PROCS) {
|
||||
|
||||
}
|
||||
bpf_cgroup_release(cgrp);
|
||||
return 0;
|
||||
}
|
Loading…
Reference in a new issue