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 X-Spam-Level: X-Spam-Status: No, score=-13.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4877CC47420 for ; Wed, 30 Sep 2020 00:20:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C3225207C4 for ; Wed, 30 Sep 2020 00:20:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="RUjrkByY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728192AbgI3AUW (ORCPT ); Tue, 29 Sep 2020 20:20:22 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:49258 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728684AbgI3AUV (ORCPT ); Tue, 29 Sep 2020 20:20:21 -0400 Received: from pps.filterd (m0044010.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 08U0C7WN026510 for ; Tue, 29 Sep 2020 17:20:21 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : mime-version : content-transfer-encoding : content-type; s=facebook; bh=h3BnLxZrQ4XlvvyA1YZ1bz1YPKF17/KsDORShehfmng=; b=RUjrkByYoOI/Ktis+Vrr3pZ0Sxh9GTrGDyuJHWmQ+MKFROC2bgd9ieer/aVO2ArNz8pe O1mNXAk9PJEOZU8ybnv7StXcn+eoqcnye41u7Otz8A2wr2lWINiZMe4xESfGuqRFqxri Ad8K8eeE4M2+0hd+Yl3//aab7HzAG5ik00k= Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 33v6v42ung-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Tue, 29 Sep 2020 17:20:21 -0700 Received: from intmgw002.08.frc2.facebook.com (2620:10d:c085:208::f) by mail.thefacebook.com (2620:10d:c085:21d::4) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1979.3; Tue, 29 Sep 2020 17:20:20 -0700 Received: by devbig006.ftw2.facebook.com (Postfix, from userid 4523) id 0E51162E56EB; Tue, 29 Sep 2020 17:20:13 -0700 (PDT) From: Song Liu To: , CC: , , , , , Song Liu Subject: [PATCH v2 bpf-next] bpf: fix raw_tp test run in preempt kernel Date: Tue, 29 Sep 2020 17:20:10 -0700 Message-ID: <20200930002011.521337-1-songliubraving@fb.com> X-Mailer: git-send-email 2.24.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-FB-Internal: Safe Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-09-29_14:2020-09-29,2020-09-29 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 adultscore=0 malwarescore=0 mlxscore=0 impostorscore=0 spamscore=0 bulkscore=0 clxscore=1015 lowpriorityscore=0 mlxlogscore=739 phishscore=0 suspectscore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2009290205 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org In preempt kernel, BPF_PROG_TEST_RUN on raw_tp triggers: [ 35.874974] BUG: using smp_processor_id() in preemptible [00000000] code: new_name/87 [ 35.893983] caller is bpf_prog_test_run_raw_tp+0xd4/0x1b0 [ 35.900124] CPU: 1 PID: 87 Comm: new_name Not tainted 5.9.0-rc6-g615bd= 02bf #1 [ 35.907358] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014 [ 35.916941] Call Trace: [ 35.919660] dump_stack+0x77/0x9b [ 35.923273] check_preemption_disabled+0xb4/0xc0 [ 35.928376] bpf_prog_test_run_raw_tp+0xd4/0x1b0 [ 35.933872] ? selinux_bpf+0xd/0x70 [ 35.937532] __do_sys_bpf+0x6bb/0x21e0 [ 35.941570] ? find_held_lock+0x2d/0x90 [ 35.945687] ? vfs_write+0x150/0x220 [ 35.949586] do_syscall_64+0x2d/0x40 [ 35.953443] entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fix this by calling migrate_disable() before smp_processor_id(). Fixes: 1b4d60ec162f ("bpf: Enable BPF_PROG_TEST_RUN for raw_tracepoint") Reported-by: Alexei Starovoitov Signed-off-by: Song Liu --- Changes v1 =3D> v2: 1. Keep rcu_read_lock/unlock() in original places. (Alexei) 2. Use get_cpu() instead of smp_processor_id(). (Alexei) --- net/bpf/test_run.c | 19 ++++++++----------- 1 file changed, 8 insertions(+), 11 deletions(-) diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c index fde5db93507c4..c1c30a9f76f34 100644 --- a/net/bpf/test_run.c +++ b/net/bpf/test_run.c @@ -252,9 +252,7 @@ __bpf_prog_test_run_raw_tp(void *data) struct bpf_raw_tp_test_run_info *info =3D data; =20 rcu_read_lock(); - migrate_disable(); info->retval =3D BPF_PROG_RUN(info->prog, info->ctx); - migrate_enable(); rcu_read_unlock(); } =20 @@ -266,6 +264,7 @@ int bpf_prog_test_run_raw_tp(struct bpf_prog *prog, __u32 ctx_size_in =3D kattr->test.ctx_size_in; struct bpf_raw_tp_test_run_info info; int cpu =3D kattr->test.cpu, err =3D 0; + int current_cpu; =20 /* doesn't support data_in/out, ctx_out, duration, or repeat */ if (kattr->test.data_in || kattr->test.data_out || @@ -293,27 +292,25 @@ int bpf_prog_test_run_raw_tp(struct bpf_prog *prog, =20 info.prog =3D prog; =20 + current_cpu =3D get_cpu(); if ((kattr->test.flags & BPF_F_TEST_RUN_ON_CPU) =3D=3D 0 || - cpu =3D=3D smp_processor_id()) { + cpu =3D=3D current_cpu) { __bpf_prog_test_run_raw_tp(&info); - } else { + } else if (cpu >=3D nr_cpu_ids || !cpu_online(cpu)) { /* smp_call_function_single() also checks cpu_online() * after csd_lock(). However, since cpu is from user * space, let's do an extra quick check to filter out * invalid value before smp_call_function_single(). */ - if (cpu >=3D nr_cpu_ids || !cpu_online(cpu)) { err =3D -ENXIO; - goto out; - } - + } else { err =3D smp_call_function_single(cpu, __bpf_prog_test_run_raw_tp, &info, 1); - if (err) - goto out; } + put_cpu(); =20 - if (copy_to_user(&uattr->test.retval, &info.retval, sizeof(u32))) + if (!err && + copy_to_user(&uattr->test.retval, &info.retval, sizeof(u32))) err =3D -EFAULT; =20 out: --=20 2.24.1