From patchwork Tue Sep 12 07:01:45 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chuyi Zhou X-Patchwork-Id: 13380886 X-Patchwork-Delegate: bpf@iogearbox.net Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 914898F44 for ; Tue, 12 Sep 2023 07:02:07 +0000 (UTC) Received: from mail-pf1-x429.google.com (mail-pf1-x429.google.com [IPv6:2607:f8b0:4864:20::429]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DBBECE78 for ; Tue, 12 Sep 2023 00:02:06 -0700 (PDT) Received: by mail-pf1-x429.google.com with SMTP id d2e1a72fcca58-68fba57030fso1746987b3a.3 for ; Tue, 12 Sep 2023 00:02:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1694502126; x=1695106926; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=FNQpGQe4u79p1mkZVJD58U2KIJEFL4MZuGQeXTwOQ8w=; b=Dow5IJyKwkOy28TWDR9DDnjAogp9ctHCGYgTIiopVm61CJBX4KtSrMGSU1tt3U8dZX t8jMpD60rg5/hDwiqUJeq9z4WKLQwBXfV7ALggUQeh7PqPCrti/rKseXZU4/2/ivg1/M t5mdw24PCiXIwotA7LSzjM5CpbpQpODL/Dn/30HR64J/9e4rJhIpvl9l4hPrgOJbqsfJ RkROP7y53WJoqvfKDUMZYjz0QnDf7EWX/eM2mjGuGXMgnfMuOkyDw0Xe/nQTbeKaVznR bLX1GuNfRU/ADul/SXbTD7ZuEl25jbAoJdvDAO7ZRl2/CLRyqKPi+dt4vKy/NLOY/Y8K a6lA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1694502126; x=1695106926; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=FNQpGQe4u79p1mkZVJD58U2KIJEFL4MZuGQeXTwOQ8w=; b=MdJ8P76xkvOQQ6CECkhsihNtgz2m1XIW7DlktwkCEWLDIAEM9GS3yhWZ176iXxuqDP vHDhFP7I7I5xsLsNxgFEwKixJeMKQT3eKMY6vAiIx/eRPblTyNzDo4SrUSLsmabrMknu HQZitGP0uX/cQoS0KNOCAETaRgJDF2ZaLHS/gv5afU4mpUeFq9wDr7WaJIvisTSwXjAZ br6I0aL/+Wk5M9m7zyJBYbbPT3Q3fGYhk1K/UUW2zsX53OnpfxpQUyBDq49OlyTh5dqZ oQAQWg4/D8Dw1ASgla1pOP8V8QuZoxQ0JUetZ7xPb98S0ZjgzWV0MifOtzSQMuII6NHl TJFw== X-Gm-Message-State: AOJu0YyjJ2YVDHzAFpHizjJWn1dxBrxUlu2bhrPHQM8k5eLd4GbLPKOt HrWV68Trp/wylbkrmnxOh6Nc0LrIKMxdOFRElx4CnQ== X-Google-Smtp-Source: AGHT+IFrGkPdm7n165iwKopet18YYKmVo1jjoqtm9QF2jj2jLPZw8NkCsAYe/iI/yLg8hGzAh6dENw== X-Received: by 2002:a05:6a20:ce9f:b0:153:c9fa:4ed6 with SMTP id if31-20020a056a20ce9f00b00153c9fa4ed6mr8870801pzb.10.1694502126142; Tue, 12 Sep 2023 00:02:06 -0700 (PDT) Received: from n37-019-243.byted.org ([180.184.84.173]) by smtp.gmail.com with ESMTPSA id b8-20020a170902d50800b001b8953365aesm7635401plg.22.2023.09.12.00.02.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 12 Sep 2023 00:02:05 -0700 (PDT) From: Chuyi Zhou To: bpf@vger.kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@kernel.org, tj@kernel.org, linux-kernel@vger.kernel.org, Chuyi Zhou Subject: [PATCH bpf-next v2 2/6] bpf: Introduce css_task open-coded iterator kfuncs Date: Tue, 12 Sep 2023 15:01:45 +0800 Message-Id: <20230912070149.969939-3-zhouchuyi@bytedance.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20230912070149.969939-1-zhouchuyi@bytedance.com> References: <20230912070149.969939-1-zhouchuyi@bytedance.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net This patch adds kfuncs bpf_iter_css_task_{new,next,destroy} which allow creation and manipulation of struct bpf_iter_css_task in open-coded iterator style. These kfuncs actually wrapps css_task_iter_{start,next, end}. BPF programs can use these kfuncs through bpf_for_each macro for iteration of all tasks under a css. css_task_iter_*() would try to get the global spin-lock *css_set_lock*, so the bpf side has to be careful in where it allows to use this iter. Currently we only allow it in bpf_lsm and bpf iter-s. Signed-off-by: Chuyi Zhou --- include/uapi/linux/bpf.h | 4 +++ kernel/bpf/helpers.c | 3 +++ kernel/bpf/task_iter.c | 48 ++++++++++++++++++++++++++++++++++ kernel/bpf/verifier.c | 23 ++++++++++++++++ tools/include/uapi/linux/bpf.h | 4 +++ tools/lib/bpf/bpf_helpers.h | 7 +++++ 6 files changed, 89 insertions(+) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 73b155e52204..de02c0971428 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -7318,4 +7318,8 @@ struct bpf_iter_num { __u64 __opaque[1]; } __attribute__((aligned(8))); +struct bpf_iter_css_task { + __u64 __opaque[1]; +} __attribute__((aligned(8))); + #endif /* _UAPI__LINUX_BPF_H__ */ diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index b0a9834f1051..d6a16becfbb9 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -2504,6 +2504,9 @@ BTF_ID_FLAGS(func, bpf_dynptr_slice_rdwr, KF_RET_NULL) BTF_ID_FLAGS(func, bpf_iter_num_new, KF_ITER_NEW) BTF_ID_FLAGS(func, bpf_iter_num_next, KF_ITER_NEXT | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_iter_num_destroy, KF_ITER_DESTROY) +BTF_ID_FLAGS(func, bpf_iter_css_task_new, KF_ITER_NEW) +BTF_ID_FLAGS(func, bpf_iter_css_task_next, KF_ITER_NEXT | KF_RET_NULL) +BTF_ID_FLAGS(func, bpf_iter_css_task_destroy, KF_ITER_DESTROY) BTF_ID_FLAGS(func, bpf_dynptr_adjust) BTF_ID_FLAGS(func, bpf_dynptr_is_null) BTF_ID_FLAGS(func, bpf_dynptr_is_rdonly) diff --git a/kernel/bpf/task_iter.c b/kernel/bpf/task_iter.c index 7473068ed313..d8539cc05ffd 100644 --- a/kernel/bpf/task_iter.c +++ b/kernel/bpf/task_iter.c @@ -803,6 +803,54 @@ const struct bpf_func_proto bpf_find_vma_proto = { .arg5_type = ARG_ANYTHING, }; +struct bpf_iter_css_task_kern { + struct css_task_iter *css_it; +} __attribute__((aligned(8))); + +__bpf_kfunc int bpf_iter_css_task_new(struct bpf_iter_css_task *it, + struct cgroup_subsys_state *css, unsigned int flags) +{ + struct bpf_iter_css_task_kern *kit = (void *)it; + + BUILD_BUG_ON(sizeof(struct bpf_iter_css_task_kern) != sizeof(struct bpf_iter_css_task)); + BUILD_BUG_ON(__alignof__(struct bpf_iter_css_task_kern) != + __alignof__(struct bpf_iter_css_task)); + + switch (flags) { + case CSS_TASK_ITER_PROCS | CSS_TASK_ITER_THREADED: + case CSS_TASK_ITER_PROCS: + case 0: + break; + default: + return -EINVAL; + } + + kit->css_it = kzalloc(sizeof(struct css_task_iter), GFP_KERNEL); + if (!kit->css_it) + return -ENOMEM; + css_task_iter_start(css, flags, kit->css_it); + return 0; +} + +__bpf_kfunc struct task_struct *bpf_iter_css_task_next(struct bpf_iter_css_task *it) +{ + struct bpf_iter_css_task_kern *kit = (void *)it; + + if (!kit->css_it) + return NULL; + return css_task_iter_next(kit->css_it); +} + +__bpf_kfunc void bpf_iter_css_task_destroy(struct bpf_iter_css_task *it) +{ + struct bpf_iter_css_task_kern *kit = (void *)it; + + if (!kit->css_it) + return; + css_task_iter_end(kit->css_it); + kfree(kit->css_it); +} + DEFINE_PER_CPU(struct mmap_unlock_irq_work, mmap_unlock_work); static void do_mmap_read_unlock(struct irq_work *entry) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index dbba2b806017..2367483bf4c2 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -10332,6 +10332,7 @@ enum special_kfunc_type { KF_bpf_dynptr_clone, KF_bpf_percpu_obj_new_impl, KF_bpf_percpu_obj_drop_impl, + KF_bpf_iter_css_task_new, }; BTF_SET_START(special_kfunc_set) @@ -10354,6 +10355,7 @@ BTF_ID(func, bpf_dynptr_slice_rdwr) BTF_ID(func, bpf_dynptr_clone) BTF_ID(func, bpf_percpu_obj_new_impl) BTF_ID(func, bpf_percpu_obj_drop_impl) +BTF_ID(func, bpf_iter_css_task_new) BTF_SET_END(special_kfunc_set) BTF_ID_LIST(special_kfunc_list) @@ -10378,6 +10380,7 @@ BTF_ID(func, bpf_dynptr_slice_rdwr) BTF_ID(func, bpf_dynptr_clone) BTF_ID(func, bpf_percpu_obj_new_impl) BTF_ID(func, bpf_percpu_obj_drop_impl) +BTF_ID(func, bpf_iter_css_task_new) static bool is_kfunc_ret_null(struct bpf_kfunc_call_arg_meta *meta) { @@ -10902,6 +10905,20 @@ static int process_kf_arg_ptr_to_rbtree_node(struct bpf_verifier_env *env, &meta->arg_rbtree_root.field); } +static bool check_css_task_iter_allowlist(struct bpf_verifier_env *env) +{ + enum bpf_prog_type prog_type = resolve_prog_type(env->prog); + + switch (prog_type) { + case BPF_PROG_TYPE_LSM: + return true; + case BPF_TRACE_ITER: + return env->prog->aux->sleepable; + default: + return false; + } +} + static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_arg_meta *meta, int insn_idx) { @@ -11152,6 +11169,12 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ break; } case KF_ARG_PTR_TO_ITER: + if (meta->func_id == special_kfunc_list[KF_bpf_iter_css_task_new]) { + if (!check_css_task_iter_allowlist(env)) { + verbose(env, "css_task_iter is only allowed in bpf_lsm and bpf iter-s\n"); + return -EINVAL; + } + } ret = process_iter_arg(env, regno, insn_idx, meta); if (ret < 0) return ret; diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 73b155e52204..de02c0971428 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -7318,4 +7318,8 @@ struct bpf_iter_num { __u64 __opaque[1]; } __attribute__((aligned(8))); +struct bpf_iter_css_task { + __u64 __opaque[1]; +} __attribute__((aligned(8))); + #endif /* _UAPI__LINUX_BPF_H__ */ diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h index 77ceea575dc7..f48723c6c593 100644 --- a/tools/lib/bpf/bpf_helpers.h +++ b/tools/lib/bpf/bpf_helpers.h @@ -303,6 +303,13 @@ extern int bpf_iter_num_new(struct bpf_iter_num *it, int start, int end) __weak extern int *bpf_iter_num_next(struct bpf_iter_num *it) __weak __ksym; extern void bpf_iter_num_destroy(struct bpf_iter_num *it) __weak __ksym; +struct bpf_iter_css_task; +struct cgroup_subsys_state; +extern int bpf_iter_css_task_new(struct bpf_iter_css_task *it, + struct cgroup_subsys_state *css, unsigned int flags) __weak __ksym; +extern struct task_struct *bpf_iter_css_task_next(struct bpf_iter_css_task *it) __weak __ksym; +extern void bpf_iter_css_task_destroy(struct bpf_iter_css_task *it) __weak __ksym; + #ifndef bpf_for_each /* bpf_for_each(iter_type, cur_elem, args...) provides generic construct for * using BPF open-coded iterators without having to write mundane explicit