From: Chuyi Zhou <zhouchuyi@bytedance.com> mainline inclusion from mainline-v6.7-rc1 commit f49843afde6771ef6ed5d021eacafacfc98a58bf category: feature bugzilla: https://atomgit.com/openeuler/kernel/issues/8335 CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... ---------------------------------------------------------------------- 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> Signed-off-by: Luo Gengkun <luogengkun2@huawei.com> --- .../selftests/bpf/prog_tests/cgroup_iter.c | 33 ++++++++++++++ .../selftests/bpf/progs/iters_css_task.c | 44 +++++++++++++++++++ 2 files changed, 77 insertions(+) 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 @@ static void test_walk_dead_self_only(struct cgroup_iter *skel) 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; +} -- 2.34.1