From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C1D06C00144 for ; Mon, 1 Aug 2022 17:54:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233827AbiHARyq (ORCPT ); Mon, 1 Aug 2022 13:54:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60634 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233634AbiHARyj (ORCPT ); Mon, 1 Aug 2022 13:54:39 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4147213D5E for ; Mon, 1 Aug 2022 10:54:38 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id t10-20020a5b07ca000000b0066ec1bb6e2cso9081602ybq.14 for ; Mon, 01 Aug 2022 10:54:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=94uBmcLYR44gO9IwX8w38Cl0b3ucjrw05lLRZoANBEo=; b=rsW6JPNEjOByHKoZqtGJI0llTPq60KTitf7bJXV8OIcA7HWQ2jwDpIlYh4NiTbi44U /7SW+a184h2h92ey8CKe9MxNIJ5Ng8ysWl3CfH1bLJrDxBMVr9MFcETQxxfOBYswE6zA pNYteBbHgrN0aaOFqkSLuGdW2mApz5mLUYEEhkWEvi6K5ZHULL3x9tJvZ/1cYdhf7ncy 5vWXyHUIpdbK26RpZDPmzHXVDoq7xbNfAa/vJFw0n8Z0b+Tnwne4PxoLWi2BcO2bNH4A BNxxuzwmXaJjbELOSQTSuxSkFeCfifQL026l2dMv4rwxiS88sswqMQEU6E7IeermXS5K bQzw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=94uBmcLYR44gO9IwX8w38Cl0b3ucjrw05lLRZoANBEo=; b=k/Zmry64GUiCwGnwf5DAFZbb7h7CJuiv+NpYiXPmgTFTSlGr/nLGhBp7khzv3lY16/ Jyjggp3C+3m7Rh3b1svbc1AFn3tWQNHxFs7zIWlzPHxR5gKos0/OqJse7wJskJ/9jb8G 9MoDgJ/rOuvGG+cP9oNUAt+zOWaShmmMPN3wHfr84UiBW7lP8jgRYBMCIYeYYhhlg8NA 9Bav0lA8RE1/x/gtsDoUhHaQuKv1hDXjd2ANUc6H2Y6Bc144BwFmNWOnsSOf1G/ZyVp1 jdic5prBQJkc3xRaBb9vXUSO3QvizXttSZirOUgdo5nOdr3xJr0HV7OsGzIOU7j5sSjN cElA== X-Gm-Message-State: ACgBeo0PtEHIHNPJy5tyXu3ByKtFKK8nhKL1lztIqXCKaFM2nEzw3qgl pzHHvWu2fGzQlqQ2xwGEDsUfcB9a5T6BQeoapqJ6vs1ERK71j+c2HZiMJ/8uGXnz2PufGAPZpID je3lb5rP48VCpJdeaKnc8fdaiullSHAbg+dvhpgcihPpDU1EB6TUWKwTHyhQvxmQqsjQXcA== X-Google-Smtp-Source: AA6agR4qKYgij7ozdxesZZjTYakKZ8S9yFfDp/tVifPcHrXtZha2s3/p6pa83PCSOZoOwZf8F5aWclmhyE0= X-Received: from haoluo.svl.corp.google.com ([2620:15c:2d4:203:7c9:7b32:e73f:6716]) (user=haoluo job=sendgmr) by 2002:a0d:f846:0:b0:324:cb8a:e0ff with SMTP id i67-20020a0df846000000b00324cb8ae0ffmr6685761ywf.478.1659376477250; Mon, 01 Aug 2022 10:54:37 -0700 (PDT) Date: Mon, 1 Aug 2022 10:54:00 -0700 In-Reply-To: <20220801175407.2647869-1-haoluo@google.com> Message-Id: <20220801175407.2647869-2-haoluo@google.com> Mime-Version: 1.0 References: <20220801175407.2647869-1-haoluo@google.com> X-Mailer: git-send-email 2.37.1.455.g008518b4e5-goog Subject: [PATCH bpf-next v6 1/8] btf: Add a new kfunc flag which allows to mark a function to be sleepable From: Hao Luo To: linux-kernel@vger.kernel.org, bpf@vger.kernel.org, cgroups@vger.kernel.org, netdev@vger.kernel.org Cc: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Martin KaFai Lau , Song Liu , Yonghong Song , Tejun Heo , Zefan Li , KP Singh , Johannes Weiner , Michal Hocko , Benjamin Tissoires , John Fastabend , Michal Koutny , Roman Gushchin , David Rientjes , Stanislav Fomichev , Shakeel Butt , Yosry Ahmed , Hao Luo Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Benjamin Tissoires From: Benjamin Tissoires This allows to declare a kfunc as sleepable and prevents its use in a non sleepable program. Signed-off-by: Benjamin Tissoires Co-developed-by: Yosry Ahmed Signed-off-by: Yosry Ahmed Signed-off-by: Hao Luo --- Documentation/bpf/kfuncs.rst | 6 ++++++ include/linux/btf.h | 1 + kernel/bpf/btf.c | 9 +++++++++ 3 files changed, 16 insertions(+) diff --git a/Documentation/bpf/kfuncs.rst b/Documentation/bpf/kfuncs.rst index c0b7dae6dbf5..c8b21de1c772 100644 --- a/Documentation/bpf/kfuncs.rst +++ b/Documentation/bpf/kfuncs.rst @@ -146,6 +146,12 @@ that operate (change some property, perform some operation) on an object that was obtained using an acquire kfunc. Such kfuncs need an unchanged pointer to ensure the integrity of the operation being performed on the expected object. +2.4.6 KF_SLEEPABLE flag +----------------------- + +The KF_SLEEPABLE flag is used for kfuncs that may sleep. Such kfuncs can only +be called by sleepable BPF programs (BPF_F_SLEEPABLE). + 2.5 Registering the kfuncs -------------------------- diff --git a/include/linux/btf.h b/include/linux/btf.h index cdb376d53238..976cbdd2981f 100644 --- a/include/linux/btf.h +++ b/include/linux/btf.h @@ -49,6 +49,7 @@ * for this case. */ #define KF_TRUSTED_ARGS (1 << 4) /* kfunc only takes trusted pointer arguments */ +#define KF_SLEEPABLE (1 << 5) /* kfunc may sleep */ struct btf; struct btf_member; diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 7e64447659f3..d3e4c86b8fcd 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -6175,6 +6175,7 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env, { enum bpf_prog_type prog_type = resolve_prog_type(env->prog); bool rel = false, kptr_get = false, trusted_arg = false; + bool sleepable = false; struct bpf_verifier_log *log = &env->log; u32 i, nargs, ref_id, ref_obj_id = 0; bool is_kfunc = btf_is_kernel(btf); @@ -6212,6 +6213,7 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env, rel = kfunc_flags & KF_RELEASE; kptr_get = kfunc_flags & KF_KPTR_GET; trusted_arg = kfunc_flags & KF_TRUSTED_ARGS; + sleepable = kfunc_flags & KF_SLEEPABLE; } /* check that BTF function arguments match actual types that the @@ -6419,6 +6421,13 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env, func_name); return -EINVAL; } + + if (sleepable && !env->prog->aux->sleepable) { + bpf_log(log, "kernel function %s is sleepable but the program is not\n", + func_name); + return -EINVAL; + } + /* returns argument register number > 0 in case of reference release kfunc */ return rel ? ref_regno : 0; } -- 2.37.1.455.g008518b4e5-goog