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 6F687C433F5 for ; Mon, 24 Jan 2022 18:57:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344475AbiAXS5g (ORCPT ); Mon, 24 Jan 2022 13:57:36 -0500 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:32404 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344558AbiAXSys (ORCPT ); Mon, 24 Jan 2022 13:54:48 -0500 Received: from pps.filterd (m0109332.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.1.2/8.16.1.2) with ESMTP id 20OHViTx019368 for ; Mon, 24 Jan 2022 10:54:47 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : content-type; s=facebook; bh=TDgsCBwNGZUO87e8EAoWyKnNI15J9DuFZCAQMRJPj1M=; b=WkG8/UALNMbjocKNYx6RvW3AO3nO1DNUhrrY966NjQzSLNgdf2bi/zPSPxSCROdUsHQW 2n2anf6a1YCFNzJrWRAuhA+W5KDkb2wNTxT0sjZPqfJdtGv0cY3hHtbtC8edc+UgYx1q xszT7pxNgmW/9iOJtTgMCR0EpZoZz6I9fRk= Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 3dswd8j5cj-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Mon, 24 Jan 2022 10:54:47 -0800 Received: from twshared14140.35.frc1.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:83::4) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.21; Mon, 24 Jan 2022 10:54:47 -0800 Received: by devbig014.vll3.facebook.com (Postfix, from userid 7377) id B0F879816156; Mon, 24 Jan 2022 10:54:40 -0800 (PST) From: Kenny Yu To: CC: , , , , , , , Subject: [PATCH v7 bpf-next 1/4] bpf: Add support for bpf iterator programs to use sleepable helpers Date: Mon, 24 Jan 2022 10:54:00 -0800 Message-ID: <20220124185403.468466-2-kennyyu@fb.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220124185403.468466-1-kennyyu@fb.com> References: <20220113233158.1582743-1-kennyyu@fb.com> <20220124185403.468466-1-kennyyu@fb.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-FB-Internal: Safe Content-Type: text/plain X-Proofpoint-GUID: m2BvRcZp_W5NUsUb_iI2JkCUWGPtf8Z5 X-Proofpoint-ORIG-GUID: m2BvRcZp_W5NUsUb_iI2JkCUWGPtf8Z5 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.816,Hydra:6.0.425,FMLib:17.11.62.513 definitions=2022-01-24_09,2022-01-24_02,2021-12-02_01 X-Proofpoint-Spam-Details: rule=fb_outbound_notspam policy=fb_outbound score=0 priorityscore=1501 lowpriorityscore=0 spamscore=0 adultscore=0 phishscore=0 mlxscore=0 impostorscore=0 bulkscore=0 mlxlogscore=896 malwarescore=0 clxscore=1015 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2201110000 definitions=main-2201240124 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org This patch allows bpf iterator programs to use sleepable helpers by changing `bpf_iter_run_prog` to use the appropriate synchronization. With sleepable bpf iterator programs, we can no longer use `rcu_read_lock()` and must use `rcu_read_lock_trace()` instead to protect the bpf program. Signed-off-by: Kenny Yu --- kernel/bpf/bpf_iter.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c index b7aef5b3416d..110029ede71e 100644 --- a/kernel/bpf/bpf_iter.c +++ b/kernel/bpf/bpf_iter.c @@ -5,6 +5,7 @@ #include #include #include +#include =20 struct bpf_iter_target_info { struct list_head list; @@ -684,11 +685,20 @@ int bpf_iter_run_prog(struct bpf_prog *prog, void *= ctx) { int ret; =20 - rcu_read_lock(); - migrate_disable(); - ret =3D bpf_prog_run(prog, ctx); - migrate_enable(); - rcu_read_unlock(); + if (prog->aux->sleepable) { + rcu_read_lock_trace(); + migrate_disable(); + might_fault(); + ret =3D bpf_prog_run(prog, ctx); + migrate_enable(); + rcu_read_unlock_trace(); + } else { + rcu_read_lock(); + migrate_disable(); + ret =3D bpf_prog_run(prog, ctx); + migrate_enable(); + rcu_read_unlock(); + } =20 /* bpf program can only return 0 or 1: * 0 : okay --=20 2.30.2