From 41d76c721c5c743470078d30e9bb8df08c489b1c Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Wed, 30 Nov 2022 21:04:49 -0800 Subject: [PATCH] bpf: Add sleepable prog tests for cgrp local storage Add three tests for cgrp local storage support for sleepable progs. Two tests can load and run properly, one for cgroup_iter, another for passing current->cgroups->dfl_cgrp to bpf_cgrp_storage_get() helper. One test has bpf_rcu_read_lock() and failed to load. Signed-off-by: Yonghong Song Link: https://lore.kernel.org/r/20221201050449.2785613-1-yhs@fb.com Signed-off-by: Alexei Starovoitov --- .../bpf/prog_tests/cgrp_local_storage.c | 94 +++++++++++++++++++ .../selftests/bpf/progs/cgrp_ls_sleepable.c | 80 ++++++++++++++++ 2 files changed, 174 insertions(+) create mode 100644 tools/testing/selftests/bpf/progs/cgrp_ls_sleepable.c diff --git a/tools/testing/selftests/bpf/prog_tests/cgrp_local_storage.c b/tools/testing/selftests/bpf/prog_tests/cgrp_local_storage.c index 1c30412ba132..33a2776737e7 100644 --- a/tools/testing/selftests/bpf/prog_tests/cgrp_local_storage.c +++ b/tools/testing/selftests/bpf/prog_tests/cgrp_local_storage.c @@ -10,7 +10,9 @@ #include "cgrp_ls_recursion.skel.h" #include "cgrp_ls_attach_cgroup.skel.h" #include "cgrp_ls_negative.skel.h" +#include "cgrp_ls_sleepable.skel.h" #include "network_helpers.h" +#include "cgroup_helpers.h" struct socket_cookie { __u64 cookie_key; @@ -150,14 +152,100 @@ static void test_negative(void) } } +static void test_cgroup_iter_sleepable(int cgroup_fd, __u64 cgroup_id) +{ + DECLARE_LIBBPF_OPTS(bpf_iter_attach_opts, opts); + union bpf_iter_link_info linfo; + struct cgrp_ls_sleepable *skel; + struct bpf_link *link; + int err, iter_fd; + char buf[16]; + + skel = cgrp_ls_sleepable__open(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return; + + bpf_program__set_autoload(skel->progs.cgroup_iter, true); + err = cgrp_ls_sleepable__load(skel); + if (!ASSERT_OK(err, "skel_load")) + goto out; + + memset(&linfo, 0, sizeof(linfo)); + linfo.cgroup.cgroup_fd = cgroup_fd; + linfo.cgroup.order = BPF_CGROUP_ITER_SELF_ONLY; + opts.link_info = &linfo; + opts.link_info_len = sizeof(linfo); + link = bpf_program__attach_iter(skel->progs.cgroup_iter, &opts); + if (!ASSERT_OK_PTR(link, "attach_iter")) + goto out; + + iter_fd = bpf_iter_create(bpf_link__fd(link)); + if (!ASSERT_GE(iter_fd, 0, "iter_create")) + goto out; + + /* trigger the program run */ + (void)read(iter_fd, buf, sizeof(buf)); + + ASSERT_EQ(skel->bss->cgroup_id, cgroup_id, "cgroup_id"); + + close(iter_fd); +out: + cgrp_ls_sleepable__destroy(skel); +} + +static void test_no_rcu_lock(__u64 cgroup_id) +{ + struct cgrp_ls_sleepable *skel; + int err; + + skel = cgrp_ls_sleepable__open(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return; + + skel->bss->target_pid = syscall(SYS_gettid); + + bpf_program__set_autoload(skel->progs.no_rcu_lock, true); + err = cgrp_ls_sleepable__load(skel); + if (!ASSERT_OK(err, "skel_load")) + goto out; + + err = cgrp_ls_sleepable__attach(skel); + if (!ASSERT_OK(err, "skel_attach")) + goto out; + + syscall(SYS_getpgid); + + ASSERT_EQ(skel->bss->cgroup_id, cgroup_id, "cgroup_id"); +out: + cgrp_ls_sleepable__destroy(skel); +} + +static void test_rcu_lock(void) +{ + struct cgrp_ls_sleepable *skel; + int err; + + skel = cgrp_ls_sleepable__open(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return; + + bpf_program__set_autoload(skel->progs.yes_rcu_lock, true); + err = cgrp_ls_sleepable__load(skel); + ASSERT_ERR(err, "skel_load"); + + cgrp_ls_sleepable__destroy(skel); +} + void test_cgrp_local_storage(void) { + __u64 cgroup_id; int cgroup_fd; cgroup_fd = test__join_cgroup("/cgrp_local_storage"); if (!ASSERT_GE(cgroup_fd, 0, "join_cgroup /cgrp_local_storage")) return; + cgroup_id = get_cgroup_id("/cgrp_local_storage"); if (test__start_subtest("tp_btf")) test_tp_btf(cgroup_fd); if (test__start_subtest("attach_cgroup")) @@ -166,6 +254,12 @@ void test_cgrp_local_storage(void) test_recursion(cgroup_fd); if (test__start_subtest("negative")) test_negative(); + if (test__start_subtest("cgroup_iter_sleepable")) + test_cgroup_iter_sleepable(cgroup_fd, cgroup_id); + if (test__start_subtest("no_rcu_lock")) + test_no_rcu_lock(cgroup_id); + if (test__start_subtest("rcu_lock")) + test_rcu_lock(); close(cgroup_fd); } diff --git a/tools/testing/selftests/bpf/progs/cgrp_ls_sleepable.c b/tools/testing/selftests/bpf/progs/cgrp_ls_sleepable.c new file mode 100644 index 000000000000..2d11ed528b6f --- /dev/null +++ b/tools/testing/selftests/bpf/progs/cgrp_ls_sleepable.c @@ -0,0 +1,80 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */ + +#include "bpf_iter.h" +#include +#include +#include "bpf_misc.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"); + +__u32 target_pid; +__u64 cgroup_id; + +void bpf_rcu_read_lock(void) __ksym; +void bpf_rcu_read_unlock(void) __ksym; + +SEC("?iter.s/cgroup") +int cgroup_iter(struct bpf_iter__cgroup *ctx) +{ + struct seq_file *seq = ctx->meta->seq; + struct cgroup *cgrp = ctx->cgroup; + long *ptr; + + if (cgrp == NULL) + return 0; + + ptr = bpf_cgrp_storage_get(&map_a, cgrp, 0, + BPF_LOCAL_STORAGE_GET_F_CREATE); + if (ptr) + cgroup_id = cgrp->kn->id; + return 0; +} + +SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") +int no_rcu_lock(void *ctx) +{ + struct task_struct *task; + struct cgroup *cgrp; + long *ptr; + + task = bpf_get_current_task_btf(); + if (task->pid != target_pid) + return 0; + + /* ptr_to_btf_id semantics. should work. */ + cgrp = task->cgroups->dfl_cgrp; + ptr = bpf_cgrp_storage_get(&map_a, cgrp, 0, + BPF_LOCAL_STORAGE_GET_F_CREATE); + if (ptr) + cgroup_id = cgrp->kn->id; + return 0; +} + +SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") +int yes_rcu_lock(void *ctx) +{ + struct task_struct *task; + struct cgroup *cgrp; + long *ptr; + + task = bpf_get_current_task_btf(); + if (task->pid != target_pid) + return 0; + + bpf_rcu_read_lock(); + cgrp = task->cgroups->dfl_cgrp; + /* cgrp is untrusted and cannot pass to bpf_cgrp_storage_get() helper. */ + ptr = bpf_cgrp_storage_get(&map_a, cgrp, 0, BPF_LOCAL_STORAGE_GET_F_CREATE); + if (ptr) + cgroup_id = cgrp->kn->id; + bpf_rcu_read_unlock(); + return 0; +}