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=-6.8 required=3.0 tests=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 autolearn=ham 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 93369CA9EA9 for ; Fri, 18 Oct 2019 16:51:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5EC7D20854 for ; Fri, 18 Oct 2019 16:51:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="mKJbX7cJ"; dkim=pass (1024-bit key) header.d=fb.onmicrosoft.com header.i=@fb.onmicrosoft.com header.b="A8pVG7d7" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392848AbfJRQv2 (ORCPT ); Fri, 18 Oct 2019 12:51:28 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:24802 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391295AbfJRQv1 (ORCPT ); Fri, 18 Oct 2019 12:51:27 -0400 Received: from pps.filterd (m0109331.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id x9IGmV8q024456; Fri, 18 Oct 2019 09:51:10 -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=VQMzERJIgKDvJJ8XljvowSvQSkNk92XbhSPLa6Adcjo=; b=mKJbX7cJiEtclEHq2tMFo/0nHqCXYVzkJIDgrFQMORMojTRrvEntR9ypGRTSFusistmJ AQCBYmZP7D4Ynm3RHy5gPMKzPtmci2iJ0rJ5Up+CrBeFLjuxC3dsKRb/ZNvFWxboGmX5 DFAZUsPf2LJj9As50S2Zq1Haq2Wwj0zBeA8= Received: from mail.thefacebook.com (mailout.thefacebook.com [199.201.64.23]) by mx0a-00082601.pphosted.com with ESMTP id 2vpw9rcp72-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT); Fri, 18 Oct 2019 09:51:10 -0700 Received: from prn-hub01.TheFacebook.com (2620:10d:c081:35::125) by prn-hub05.TheFacebook.com (2620:10d:c081:35::129) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.1.1713.5; Fri, 18 Oct 2019 09:51:08 -0700 Received: from NAM03-CO1-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, 18 Oct 2019 09:51:08 -0700 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=DHbeRblmVArlHI/H/crk9LddmZWFCEBX3L3MsEp0vEH7u660Ep+jBtwnFAOFrJc82vg8RpI+DY/XSecjI3n6j+e4TgoAhlyR1kJ3jha91PNDX/UaUaJHrOJZ0elYox7MOsIpWe6SjMcE5uDaPePHgqDbOTxnZCqbYg9zTXtkgpTvOVTGk5787CdqPHRhd+C/+c/oa3oR4HZndE5lzACaJOaLjFKpNlekUyjWSlxNADaVXQQBqSbDpcEJHcgQNWBKj/5ZufWZEbFEzarUcXj0Ur3Gzgidiees4zSQhta8Vh964zpMGKUL2FHRdUT9IXvM4lukFky1DIz9+CE1XxKIWw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=VQMzERJIgKDvJJ8XljvowSvQSkNk92XbhSPLa6Adcjo=; b=AApMsir/kaC46jc+JNQiyTF7SYDIJDhY1xQk5HgCZl1f0IUEOQ3i+Pp52dfx8CKKla+XWPUDmJnsa9TLvzTzzCZaPU2mdsJ8QOOY7+THZUeJL0QUv39IhdcZWUVSNz+GdG81kQCAJkYDwze4N0FMrpIo04irbnXBSyPM+gqeCHjX4K7RpB+tokOjz/YMSOKzsI/Fimr6aI4NO7xjtPVCBBcTKATx3iV0CcKu67VcxdakjUXgkev0milu+ZDrKS1jTp0w4a4D9LvUgEG0TBlzK6lHr7rSAz+FK9i17SzjHyHEU1UnyivyevIAYXIdMlQ6xn1Y15yUGg7nLND6EzeC6w== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=fb.com; dmarc=pass action=none header.from=fb.com; dkim=pass header.d=fb.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.onmicrosoft.com; s=selector2-fb-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=VQMzERJIgKDvJJ8XljvowSvQSkNk92XbhSPLa6Adcjo=; b=A8pVG7d7Swy5MvWh8fE7Oi/j46uJNv3HQimASVbahnOnSyCi/KYieaD+iBtMiLZ5OcR6v8jzcp93RNAGp/P3/28u9OwPofhPFyA89A1sTYRmmh3Xdho1ItrazxLN5+QJUGOlSKoaIyFEvl/YkyTFS+cW8xFQ/yI8ttJmMBV39k0= Received: from MN2PR15MB3213.namprd15.prod.outlook.com (20.179.21.76) by MN2PR15MB3037.namprd15.prod.outlook.com (20.178.254.81) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2347.22; Fri, 18 Oct 2019 16:50:57 +0000 Received: from MN2PR15MB3213.namprd15.prod.outlook.com ([fe80::d5a4:a2a6:a805:6647]) by MN2PR15MB3213.namprd15.prod.outlook.com ([fe80::d5a4:a2a6:a805:6647%7]) with mapi id 15.20.2347.024; Fri, 18 Oct 2019 16:50:57 +0000 From: Martin Lau To: =?iso-8859-1?Q?Toke_H=F8iland-J=F8rgensen?= CC: "daniel@iogearbox.net" , Alexei Starovoitov , "bpf@vger.kernel.org" , "netdev@vger.kernel.org" , Tetsuo Handa Subject: Re: [PATCH bpf v2] xdp: Handle device unregister for devmap_hash map type Thread-Topic: [PATCH bpf v2] xdp: Handle device unregister for devmap_hash map type Thread-Index: AQHVhNkLfZlWSO7mI0yzFNGdtyQQtadfMRqAgAECVICAAGtDgA== Date: Fri, 18 Oct 2019 16:50:57 +0000 Message-ID: <20191018165049.rm6du3yq2e4vg45h@kafai-mbp> References: <20191017105232.2806390-1-toke@redhat.com> <20191017190219.hpphf7jnyn6xapb6@kafai-mbp.dhcp.thefacebook.com> <87pniue4cw.fsf@toke.dk> In-Reply-To: <87pniue4cw.fsf@toke.dk> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-clientproxiedby: CO2PR05CA0092.namprd05.prod.outlook.com (2603:10b6:104:1::18) To MN2PR15MB3213.namprd15.prod.outlook.com (2603:10b6:208:3d::12) x-ms-exchange-messagesentrepresentingtype: 1 x-originating-ip: [2620:10d:c090:200::2:a4bc] x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: 5101464d-b973-43db-a4e7-08d753eb58f7 x-ms-traffictypediagnostic: MN2PR15MB3037: x-ms-exchange-transport-forked: True x-microsoft-antispam-prvs: x-ms-oob-tlc-oobclassifiers: OLM:5516; x-forefront-prvs: 01949FE337 x-forefront-antispam-report: SFV:NSPM;SFS:(10019020)(7916004)(396003)(366004)(346002)(376002)(136003)(39860400002)(199004)(189003)(66476007)(66946007)(6486002)(2906002)(4326008)(9686003)(5660300002)(1076003)(64756008)(66556008)(66574012)(66446008)(6246003)(6512007)(6436002)(33716001)(14454004)(8936002)(86362001)(478600001)(8676002)(7736002)(54906003)(11346002)(6916009)(316002)(81156014)(305945005)(446003)(476003)(71200400001)(81166006)(6506007)(25786009)(99286004)(46003)(71190400001)(6116002)(486006)(102836004)(229853002)(52116002)(186003)(76176011)(256004)(386003)(14444005);DIR:OUT;SFP:1102;SCL:1;SRVR:MN2PR15MB3037;H:MN2PR15MB3213.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: BCL:0; x-microsoft-antispam-message-info: GUVWvdPyE79UBoF9V6+oe1aA4siVZlvi2RxwqhqjcXrW0TmjUTS1SGcdQPUNAWG8u5eeXoM16M4KrpnoVJxEnsFppVD5Nj/9H2y2iOxd2ak75uskgfXdWmrlfpzMQoXiq1HeE4Z1jbfzwT71LR8/LHtxLm9ydVHK1RB8yAbJZbZkP54ZF957ZZCWzPTDg7JDlUIdafX5crJEqRoTs7HoOluFc7P5ZDtPErOZ0/ocFPu67qKEPnbr2hHoGPO1hhUaHOyWL3EWJj/SLKnSCe9FAjnajkaDFRoMYfr5UN4/IvKkVx9YCjC8Ep/bRWpr83YqG/5Hf0oUeGopcKgTBTm7IrL5JDKFNUvIjaeYr9K51vLynU+7+AdkU1C2xSyyeCoSG8ab+7NttiCjq+xKR6ZRjNcai6yE2/LuJVxVrVbC1BM= Content-Type: text/plain; charset="iso-8859-1" Content-ID: <160DED47FB3C1E429E98868CFB1A58F8@namprd15.prod.outlook.com> Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-MS-Exchange-CrossTenant-Network-Message-Id: 5101464d-b973-43db-a4e7-08d753eb58f7 X-MS-Exchange-CrossTenant-originalarrivaltime: 18 Oct 2019 16:50:57.3917 (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: K39vKxAAdLVU6qiUHHefDhgDvRm0yDyLhCSQXPybtaeMwIbtOOqaJ1Fe+Uvw++Yo X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN2PR15MB3037 X-OriginatorOrg: fb.com X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.95,1.0.8 definitions=2019-10-18_04:2019-10-18,2019-10-18 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 mlxlogscore=554 lowpriorityscore=0 mlxscore=0 suspectscore=0 phishscore=0 clxscore=1015 adultscore=0 spamscore=0 bulkscore=0 priorityscore=1501 malwarescore=0 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1908290000 definitions=main-1910180153 X-FB-Internal: deliver Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Fri, Oct 18, 2019 at 12:26:55PM +0200, Toke H=F8iland-J=F8rgensen wrote: > Martin Lau writes: >=20 > > On Thu, Oct 17, 2019 at 12:52:32PM +0200, Toke H=F8iland-J=F8rgensen wr= ote: > >> It seems I forgot to add handling of devmap_hash type maps to the devi= ce > >> unregister hook for devmaps. This omission causes devices to not be > >> properly released, which causes hangs. > >>=20 > >> Fix this by adding the missing handler. > >>=20 > >> Fixes: 6f9d451ab1a3 ("xdp: Add devmap_hash map type for looking up dev= ices by hashed index") > >> Reported-by: Tetsuo Handa > >> Signed-off-by: Toke H=F8iland-J=F8rgensen > >> --- > >> v2: > >> - Grab the update lock while walking the map and removing entries. > >>=20 > >> kernel/bpf/devmap.c | 37 +++++++++++++++++++++++++++++++++++++ > >> 1 file changed, 37 insertions(+) > >>=20 > >> diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c > >> index d27f3b60ff6d..a0a1153da5ae 100644 > >> --- a/kernel/bpf/devmap.c > >> +++ b/kernel/bpf/devmap.c > >> @@ -719,6 +719,38 @@ const struct bpf_map_ops dev_map_hash_ops =3D { > >> .map_check_btf =3D map_check_no_btf, > >> }; > >> =20 > >> +static void dev_map_hash_remove_netdev(struct bpf_dtab *dtab, > >> + struct net_device *netdev) > >> +{ > >> + unsigned long flags; > >> + int i; > > dtab->n_buckets is u32. >=20 > Oh, right, will fix. >=20 > >> + > >> + spin_lock_irqsave(&dtab->index_lock, flags); > >> + for (i =3D 0; i < dtab->n_buckets; i++) { > >> + struct bpf_dtab_netdev *dev, *odev; > >> + struct hlist_head *head; > >> + > >> + head =3D dev_map_index_hash(dtab, i); > >> + dev =3D hlist_entry_safe(rcu_dereference_raw(hlist_first_rcu(head))= , > > The spinlock has already been held. Is rcu_deref still needed? >=20 > I guess it's not strictly needed, but since it's an rcu-protected list, > and hlist_first_rcu() returns an __rcu-annotated type, I think we will > get a 'sparse' warning if it's omitted, no? >=20 > And since it's just a READ_ONCE, it doesn't actually hurt since this is > not the fast path, so I'd lean towards just keeping it? WDYT? > Can hlist_for_each_safe() be used instead then? A bonus is the following long line will go away. I think the change will be simpler also. > + struct bpf_dtab_netdev, > + index_hlist); > + > + while (dev) { > + odev =3D (netdev =3D=3D dev->dev) ? dev : NULL; > + dev =3D hlist_entry_safe(rcu_dereference_raw(hlist_= next_rcu(&dev->index_hlist)), > + struct bpf_dtab_netdev, > + index_hlist); > + > + if (odev) { > + hlist_del_rcu(&odev->index_hlist); > + call_rcu(&odev->rcu, > + __dev_map_entry_free); > + } > + } > + } > + spin_unlock_irqrestore(&dtab->index_lock, flags); > +} > +