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=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 073BDC282E1 for ; Fri, 24 May 2019 21:41:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C817F217D7 for ; Fri, 24 May 2019 21:41:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="AK5XWV5G"; dkim=pass (1024-bit key) header.d=fb.onmicrosoft.com header.i=@fb.onmicrosoft.com header.b="qSIuk9ZG" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404328AbfEXVlF (ORCPT ); Fri, 24 May 2019 17:41:05 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:48918 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404277AbfEXVlD (ORCPT ); Fri, 24 May 2019 17:41:03 -0400 Received: from pps.filterd (m0109331.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x4OLbehw010636; Fri, 24 May 2019 14:40:43 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : references : in-reply-to : content-type : content-id : content-transfer-encoding : mime-version; s=facebook; bh=833M6gQ2Lc6X7v1EvYyqYf2ze/A0atFyhkbjTieKZoY=; b=AK5XWV5G4EOoxW13QnMyCxFvplkw89yIBF8aaWwGNHUkB/h/YN/r3hqiU5seg7efJCvJ eNNLoxohr6OGJDwjdpsziYsBkDKIwuKsGXEek9C14sq9b48iEUQjCTo+mpgbQHjVrFBO 3tKMVGTPPlchFfdrifvYlY1iY/8vqqCZWs8= Received: from mail.thefacebook.com (mailout.thefacebook.com [199.201.64.23]) by mx0a-00082601.pphosted.com with ESMTP id 2spk3u9841-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT); Fri, 24 May 2019 14:40:43 -0700 Received: from prn-hub01.TheFacebook.com (2620:10d:c081:35::125) by prn-hub04.TheFacebook.com (2620:10d:c081:35::128) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.1.1713.5; Fri, 24 May 2019 14:40:41 -0700 Received: from NAM02-SN1-obe.outbound.protection.outlook.com (192.168.54.28) by o365-in.thefacebook.com (192.168.16.25) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.1.1713.5 via Frontend Transport; Fri, 24 May 2019 14:40:41 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.onmicrosoft.com; s=selector1-fb-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=833M6gQ2Lc6X7v1EvYyqYf2ze/A0atFyhkbjTieKZoY=; b=qSIuk9ZG7+33t1+eALaCAnwb3/BeLYrYju9ZRKg6Ep9PrY+XHSI3gYgPgWyK9xhWZ9qv399AUOiopPgPr7C56vlb2LFzOr5uzWvbREfEpOFvC0aFmygiHf5Jhuewcbz2b9wOW4sfJh4kTPYElFoQNN4j4igSAXM4hNEGF9PzS8U= Received: from BYAPR15MB2631.namprd15.prod.outlook.com (20.179.156.24) by BYAPR15MB2839.namprd15.prod.outlook.com (20.178.206.24) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.1922.15; Fri, 24 May 2019 21:40:39 +0000 Received: from BYAPR15MB2631.namprd15.prod.outlook.com ([fe80::d4f6:b485:69ee:fd9a]) by BYAPR15MB2631.namprd15.prod.outlook.com ([fe80::d4f6:b485:69ee:fd9a%7]) with mapi id 15.20.1922.018; Fri, 24 May 2019 21:40:39 +0000 From: Roman Gushchin To: Alexei Starovoitov CC: Alexei Starovoitov , "bpf@vger.kernel.org" , Daniel Borkmann , "netdev@vger.kernel.org" , Tejun Heo , Kernel Team , "cgroups@vger.kernel.org" , Stanislav Fomichev , "Yonghong Song" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH v3 bpf-next 0/4] cgroup bpf auto-detachment Thread-Topic: [PATCH v3 bpf-next 0/4] cgroup bpf auto-detachment Thread-Index: AQHVEaBBRG5VueSSb0OqGPP4SAddC6Z6xP6AgAAKYwA= Date: Fri, 24 May 2019 21:40:39 +0000 Message-ID: <20190524214032.GA15067@castle> References: <20190523194532.2376233-1-guro@fb.com> <20190524210321.tzpt7ilaasaagtou@ast-mbp.dhcp.thefacebook.com> In-Reply-To: <20190524210321.tzpt7ilaasaagtou@ast-mbp.dhcp.thefacebook.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-clientproxiedby: MWHPR22CA0026.namprd22.prod.outlook.com (2603:10b6:300:69::12) To BYAPR15MB2631.namprd15.prod.outlook.com (2603:10b6:a03:152::24) x-ms-exchange-messagesentrepresentingtype: 1 x-originating-ip: [2620:10d:c090:180::b702] x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: 550932dd-bd39-4835-1407-08d6e09076be x-microsoft-antispam: BCL:0;PCL:0;RULEID:(2390118)(7020095)(4652040)(8989299)(4534185)(4627221)(201703031133081)(201702281549075)(8990200)(5600141)(711020)(4605104)(2017052603328)(7193020);SRVR:BYAPR15MB2839; x-ms-traffictypediagnostic: BYAPR15MB2839: x-microsoft-antispam-prvs: x-ms-oob-tlc-oobclassifiers: OLM:8273; x-forefront-prvs: 0047BC5ADE x-forefront-antispam-report: SFV:NSPM;SFS:(10019020)(7916004)(396003)(346002)(136003)(376002)(39860400002)(366004)(199004)(189003)(46003)(6916009)(11346002)(14454004)(5660300002)(76176011)(446003)(102836004)(33656002)(486006)(478600001)(386003)(68736007)(33716001)(25786009)(6506007)(66556008)(66476007)(66446008)(66946007)(64756008)(305945005)(9686003)(6512007)(1076003)(73956011)(6486002)(229853002)(256004)(14444005)(5024004)(186003)(71200400001)(316002)(71190400001)(8676002)(7736002)(53936002)(6246003)(476003)(2906002)(6436002)(4326008)(81156014)(81166006)(99286004)(8936002)(52116002)(86362001)(6116002)(54906003);DIR:OUT;SFP:1102;SCL:1;SRVR:BYAPR15MB2839;H:BYAPR15MB2631.namprd15.prod.outlook.com;FPR:;SPF:None;LANG:en;PTR:InfoNoRecords;A:1;MX:1; received-spf: None (protection.outlook.com: fb.com does not designate permitted sender hosts) x-ms-exchange-senderadcheck: 1 x-microsoft-antispam-message-info: RGlk/k4wjY1EuEZijMOvBg4nfI9BvBJ2rhQO0ySL7lxqMRIwRKmJZudDQQ4HaQXSm5dUKYKQH2sDGnDdltyysb4Hs6fAC+PctQQlNhyvfdfqaSyfbIi/GngKRBQJnEqiIbBirVfvNEPsAMWoDlNu3dwiRsvAGCfZVOnAawyidP4pA/OSDYwbBmS/AQPcdFaPBa2uYNYWCSjorwLxLvte5FVD6XIVtPtmC13NKy+E0tU885ibgUpuMmD9VvApKn6m3VKT3oRf+X/Q9XNJ9P1LZ+MKOVUWOyaato+vL+qEN1yGZE+pPkyN1P4uX7Z/NqRg1cMQeuRUESOc20j8F8J+Qu2VpFgxwT9t9x3m5W5KjIl0k06ntUMLIeR+WTl6mo7USJn69dsOaXnFYi3QbHLVwPSkFGXQCm1A18Pn5EiDodU= Content-Type: text/plain; charset="us-ascii" Content-ID: <4B9034D8D4595A4EAB3AEF55618767B8@namprd15.prod.outlook.com> Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-MS-Exchange-CrossTenant-Network-Message-Id: 550932dd-bd39-4835-1407-08d6e09076be X-MS-Exchange-CrossTenant-originalarrivaltime: 24 May 2019 21:40:39.4543 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 8ae927fe-1255-47a7-a2af-5f3a069daaa2 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: guro@fb.com X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR15MB2839 X-OriginatorOrg: fb.com X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-05-24_08:,, signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1905240141 X-FB-Internal: deliver Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 24, 2019 at 02:03:23PM -0700, Alexei Starovoitov wrote: > On Thu, May 23, 2019 at 12:45:28PM -0700, Roman Gushchin wrote: > > This patchset implements a cgroup bpf auto-detachment functionality: > > bpf programs are detached as soon as possible after removal of the > > cgroup, without waiting for the release of all associated resources. >=20 > The idea looks great, but doesn't quite work: >=20 > $ ./test_cgroup_attach > #override:PASS > [ 66.475219] BUG: sleeping function called from invalid context at ../i= nclude/linux/percpu-rwsem.h:34 > [ 66.476095] in_atomic(): 1, irqs_disabled(): 0, pid: 21, name: ksoftir= qd/2 > [ 66.476706] CPU: 2 PID: 21 Comm: ksoftirqd/2 Not tainted 5.2.0-rc1-002= 11-g1861420d0162 #1564 > [ 66.477595] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIO= S 1.11.0-2.el7 04/01/2014 > [ 66.478360] Call Trace: > [ 66.478591] dump_stack+0x5b/0x8b > [ 66.478892] ___might_sleep+0x22f/0x290 > [ 66.479230] cpus_read_lock+0x18/0x50 > [ 66.479550] static_key_slow_dec+0x41/0x70 > [ 66.479914] cgroup_bpf_release+0x1a6/0x400 > [ 66.480285] percpu_ref_switch_to_atomic_rcu+0x203/0x330 > [ 66.480754] rcu_core+0x475/0xcc0 > [ 66.481047] ? switch_mm_irqs_off+0x684/0xa40 > [ 66.481422] ? rcu_note_context_switch+0x260/0x260 > [ 66.481842] __do_softirq+0x1cf/0x5ff > [ 66.482174] ? takeover_tasklets+0x5f0/0x5f0 > [ 66.482542] ? smpboot_thread_fn+0xab/0x780 > [ 66.482911] run_ksoftirqd+0x1a/0x40 > [ 66.483225] smpboot_thread_fn+0x3ad/0x780 > [ 66.483583] ? sort_range+0x20/0x20 > [ 66.483894] ? __kthread_parkme+0xb0/0x190 > [ 66.484253] ? sort_range+0x20/0x20 > [ 66.484562] ? sort_range+0x20/0x20 > [ 66.484878] kthread+0x2e2/0x3e0 > [ 66.485166] ? kthread_create_worker_on_cpu+0xb0/0xb0 > [ 66.485620] ret_from_fork+0x1f/0x30 >=20 > Same test runs fine before the patches. >=20 Ouch, static_branch_dec() might block, so it's not possible to call it from percpu ref counter release callback. It's not what I expected, tbh. Good catch, thanks!