From nobody Fri Apr 26 22:59:27 2024 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 890FCC25B0C for ; Fri, 5 Aug 2022 21:49:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240663AbiHEVtQ (ORCPT ); Fri, 5 Aug 2022 17:49:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36862 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241332AbiHEVsz (ORCPT ); Fri, 5 Aug 2022 17:48:55 -0400 Received: from mail-pl1-x649.google.com (mail-pl1-x649.google.com [IPv6:2607:f8b0:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7655576965 for ; Fri, 5 Aug 2022 14:48:54 -0700 (PDT) Received: by mail-pl1-x649.google.com with SMTP id n8-20020a170902d2c800b0016edca79984so2239172plc.8 for ; Fri, 05 Aug 2022 14:48:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:references:mime-version:message-id:in-reply-to :date:from:to:cc; bh=v1NXB6wxRFohvXJoX8NOegBlamHwcU9rtOLwkpAdV8E=; b=Xi5iNcCGRKvjjsmKAwMoxe2RN0Shtls178GUOGYmKJg9FShcL+7UsiocCYRAMR2Pxf urteg3Kcvf2BVtedqJXvbj0xav+qEORWImui5J64jwmgMXMjnNZ3q/vvp+dfLyxeAlh2 otVYBS3oHXzz7vnUNWnVoSfsKL2WZoShCCXuYPDoAyfqU4HEki+CXcqbxH0FEkGUNgmt i6AAIhX4RjnAGDixu5tph7tPiPTc3nMRYBS5HxhuSbhIOjvCZJrecDCD1IEUhFSXuor0 BJ+Y2CaD0/K8kY/OL4DzpwX7tL5baRyraZhqHXhpuueVFepFUYPHJ/g4u5HxhlZcCOUH 5rbA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:references:mime-version:message-id:in-reply-to :date:x-gm-message-state:from:to:cc; bh=v1NXB6wxRFohvXJoX8NOegBlamHwcU9rtOLwkpAdV8E=; b=eq2o415W+QaQADcab3DDqxzrPVOH7xmeeASQKRX7TJaquxBtT+MoAFJsgz6UniR6dA oOfUy2IZMnbORNtqsRMgMjyjAV6Vi0fpK2/Q1MVQ7olhA6sAL49BVV/kaedNc0ggIgQV q9QbJxNSPXSEy8imJ3MU3sSZ0jS/+1J8r8yx8iMbC6g3fPbIRmi0gWxvx5cKq7cUNi23 2dvx6nRile8lJ51JD9o1he4yBNG5VXw+W0rIcGjC7i7EsWr7+QuIejk5A/6FBJLjlndd 6+LCfOlyTrRj1e9pG/G+HQdV8Fhwx3skuePGNyv5aFnkpOfUPg42x1cW4+jSn5j0YCaZ fEsQ== X-Gm-Message-State: ACgBeo2ko9T25X0o2M1vxpFZ9KdnMJfzFNBt92wTVv+J/llMoYMzYj4x va3dWfHxtcQkPjvOL4CTqf4Yfx5toqP7PCPzV6pQwceO/h7wshAeZbnCFtRm4O1ztsHqS8w39NA j6GOmwk+Jhaj6CT+ZNdzm5wicE1ps6YHuMP0W/fsvT6iOq0nXpcUwtqkKZnhxe9QqeGmYzg== X-Google-Smtp-Source: AA6agR4xcun+0LQiqLQQb/H/p8nnMeMQ8d129fBAQksFYt94EVlkuAVY8oY8cNefwuo8279BKU6BAkIKuIo= X-Received: from haoluo.svl.corp.google.com ([2620:15c:2d4:203:4f27:97db:8644:dc82]) (user=haoluo job=sendgmr) by 2002:a17:902:ef47:b0:16c:60df:3a7c with SMTP id e7-20020a170902ef4700b0016c60df3a7cmr8587705plx.9.1659736133709; Fri, 05 Aug 2022 14:48:53 -0700 (PDT) Date: Fri, 5 Aug 2022 14:48:14 -0700 In-Reply-To: <20220805214821.1058337-1-haoluo@google.com> Message-Id: <20220805214821.1058337-2-haoluo@google.com> Mime-Version: 1.0 References: <20220805214821.1058337-1-haoluo@google.com> X-Mailer: git-send-email 2.37.1.559.g78731f0fdb-goog Subject: [PATCH bpf-next v7 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 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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 opera= tion) 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 obje= ct. =20 +2.4.6 KF_SLEEPABLE flag +----------------------- + +The KF_SLEEPABLE flag is used for kfuncs that may sleep. Such kfuncs can o= nly +be called by sleepable BPF programs (BPF_F_SLEEPABLE). + 2.5 Registering the kfuncs -------------------------- =20 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 argum= ents */ +#define KF_SLEEPABLE (1 << 5) /* kfunc may sleep */ =20 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_verifi= er_env *env, { enum bpf_prog_type prog_type =3D resolve_prog_type(env->prog); bool rel =3D false, kptr_get =3D false, trusted_arg =3D false; + bool sleepable =3D false; struct bpf_verifier_log *log =3D &env->log; u32 i, nargs, ref_id, ref_obj_id =3D 0; bool is_kfunc =3D btf_is_kernel(btf); @@ -6212,6 +6213,7 @@ static int btf_check_func_arg_match(struct bpf_verifi= er_env *env, rel =3D kfunc_flags & KF_RELEASE; kptr_get =3D kfunc_flags & KF_KPTR_GET; trusted_arg =3D kfunc_flags & KF_TRUSTED_ARGS; + sleepable =3D kfunc_flags & KF_SLEEPABLE; } =20 /* check that BTF function arguments match actual types that the @@ -6419,6 +6421,13 @@ static int btf_check_func_arg_match(struct bpf_verif= ier_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 kfun= c */ return rel ? ref_regno : 0; } --=20 2.37.1.559.g78731f0fdb-goog