Received: by 2002:a5b:505:0:0:0:0:0 with SMTP id o5csp2646085ybp; Thu, 10 Oct 2019 10:22:05 -0700 (PDT) X-Google-Smtp-Source: APXvYqwvEkmropDKMDpG7wxtdOALbkkBk+7tyWN7j3WNbggh2pS9+eUtqsIVUA4dGxtdFVS+kXQM X-Received: by 2002:a50:ec96:: with SMTP id e22mr9348719edr.109.1570728125510; Thu, 10 Oct 2019 10:22:05 -0700 (PDT) ARC-Seal: i=2; a=rsa-sha256; t=1570728125; cv=pass; d=google.com; s=arc-20160816; b=axPfw46mt3gC9cf1eTlANYLih4MQOBdJKfhJ9npjtP+t6R1sZAmHFyniHoelRq1OwB MODtFwk+6AxmsLrQhAOfSwwOVU5LQAxp+YwT3VJjJOIwdz/0mqIcqva1P+r/TsHn8Fio lYN2fcuNaVLG2nR0NJ9HbI0SiVgo2ApJthOb/mS0LBrYfe5Ktx7DYShVvDS0px+jdpl1 3MeVca2wcw7j2m91c1wspaqbGQWe9jBH5CwHz7OGD60tIYMwL+0T75ez5GKmXo5bSzBL MeYBgyHovbejavtXGtLqQN6CugxkGz4ibIR+4+BmDSTsXqgk1FzZtobZcTDI19ieRIz+ Mjeg== ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:mime-version:content-transfer-encoding :content-id:content-language:accept-language:in-reply-to:references :message-id:date:thread-index:thread-topic:subject:cc:to:from :dkim-signature:dkim-signature; bh=B+5Ns28EhcwoidKDx8A4nZ9NVX+e4p+KSTMlnfKiBOU=; b=L+ZICj4dtDYkAkZJYike84zg7s/IDDs+vEo7XqJchKyj7jtucMIPmIeLlDWmhNrkb3 GTNMYhTZZTujfoRC00viOXn6IutUx+ZzvCLtpnTCMt25kqOT+fbR7nKH0xmtMTkLXHve iHW+HpOljfVUdzWOi1V1df89PPqwST6dHpJAK7GEF5SxCrBDJNXgA1jr0ZGUC/bIlSor sXhyY0equsG5uuJvR1Tc1bzGBtfGVYS7jE6qWfH8eOWQr6v51R6SBZ3xRS7KACZoAfAy baY9caLNl01p3KlkfB7n/ey3wtjOzf3WZytprS0ZuD3pwylZbLFDGkrebVU8kgHUl/8w g0mQ== ARC-Authentication-Results: i=2; mx.google.com; dkim=pass header.i=@fb.com header.s=facebook header.b=QbFLF53m; dkim=pass header.i=@fb.onmicrosoft.com header.s=selector2-fb-onmicrosoft-com header.b=XjBdI1HL; arc=pass (i=1 spf=pass spfdomain=fb.com dkim=pass dkdomain=fb.com dmarc=pass fromdomain=fb.com); spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=fb.com Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id b47si3901114edc.45.2019.10.10.10.21.42; Thu, 10 Oct 2019 10:22:05 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@fb.com header.s=facebook header.b=QbFLF53m; dkim=pass header.i=@fb.onmicrosoft.com header.s=selector2-fb-onmicrosoft-com header.b=XjBdI1HL; arc=pass (i=1 spf=pass spfdomain=fb.com dkim=pass dkdomain=fb.com dmarc=pass fromdomain=fb.com); spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=fb.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726718AbfJJRTa (ORCPT + 99 others); Thu, 10 Oct 2019 13:19:30 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:19168 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726131AbfJJRTa (ORCPT ); Thu, 10 Oct 2019 13:19:30 -0400 Received: from pps.filterd (m0001303.ppops.net [127.0.0.1]) by m0001303.ppops.net (8.16.0.42/8.16.0.42) with SMTP id x9AH7A3k018682; Thu, 10 Oct 2019 10:19:04 -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=B+5Ns28EhcwoidKDx8A4nZ9NVX+e4p+KSTMlnfKiBOU=; b=QbFLF53mDP+2IGIqH/od/bqE3rl0tl2yA8VWDwZghOiecbnxM34tgS0W6J4aouxhEhov pIJnrQ3caY0oWV1RsbsZwP/1ZG54w5X28+d097rYG9VRdvVzduFqu3UoRqcvSRBV3cj/ uIr4aK+0qwHYhzHLtCaDKOh6wp9hECBjGYA= Received: from mail.thefacebook.com (mailout.thefacebook.com [199.201.64.23]) by m0001303.ppops.net with ESMTP id 2vhyc0u2js-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT); Thu, 10 Oct 2019 10:19:04 -0700 Received: from prn-hub06.TheFacebook.com (2620:10d:c081:35::130) by prn-hub02.TheFacebook.com (2620:10d:c081:35::126) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.1.1713.5; Thu, 10 Oct 2019 10:19:03 -0700 Received: from NAM04-BN3-obe.outbound.protection.outlook.com (192.168.54.28) by o365-in.thefacebook.com (192.168.16.30) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.1.1713.5 via Frontend Transport; Thu, 10 Oct 2019 10:19:03 -0700 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=cqxpdmjr7tNbUouGHuyz558CKLKVkAIP9nnYQdgni+ff+ilBaDLL+MLEHQnHn2F7rruvVGbDweX4EM7GKhz/ySIeK4UB1R7OmSvKln4vPpocQygUawkvvwj3d0UtrCespl6c9NszvV/rgewqBDxMx9vCQVpgYQDpbVGOdVtfa0Lgx5NfWs6SVzMxh2O4NezjkZXusJ6scmB5h1g9r30CG3FVcHggJ71njzlpuu4Af4zRptKAcM9x7rV9fvdRk7afskLSMiiLzbg+V53SUe41r/5wT5+MfAvrZxUhuxjx4PSqWZmHFwTG7muMlsCxyE+KQVbjO746BQMnCU0qpwI1Ug== 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=B+5Ns28EhcwoidKDx8A4nZ9NVX+e4p+KSTMlnfKiBOU=; b=T8zcRkslhLShvtlvkZoTkndhhMCJeGKUFrYeqY6tXFo/FiLB8LXy9Umt+qUR/LKy098prk4L0K5ZLEgrIORAeBgY5Yekct5rnOMFOxMjMFq6mfXW5NEAIj8cppLuw0GLiZ1e20Gu/KSjDHSiu8Z8F5djjBPAZvBftU1XUXmTpIFJNWwFXpuliFuyo6vUcgSUZN5HHdnC7q637CLEIrGxNufTlfjFU7jgSxgCTfCOHR8IDmOrsLIqkE7QbK35qETQI6Ekiea/AWhEKA+EtwVUsZlNV3HI3GsZaYHGQC1ev+iteOJtJ7/PxjMb3ISbbRUMkdgweAgUBRdhF8KBafSyJQ== 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=B+5Ns28EhcwoidKDx8A4nZ9NVX+e4p+KSTMlnfKiBOU=; b=XjBdI1HLsHJWZv2MeRPTb3+YihL6BghT0CxLY4vgso7f1ScpHcjDab7jfX4zPl+NDM1+P3YIxewuFpuV1vPlIyieFuE4ITxVVM1OEtHYcB4IjpdCVGLCzs0wBXFVIt/Zf8/PZ6J21Xeau2m+hzmqhEK/NYwrpfUzVwFb1rCsezc= Received: from BYAPR15MB2501.namprd15.prod.outlook.com (52.135.196.11) by BYAPR15MB2663.namprd15.prod.outlook.com (20.179.156.144) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2347.16; Thu, 10 Oct 2019 17:19:01 +0000 Received: from BYAPR15MB2501.namprd15.prod.outlook.com ([fe80::c13d:be57:b216:bfa0]) by BYAPR15MB2501.namprd15.prod.outlook.com ([fe80::c13d:be57:b216:bfa0%5]) with mapi id 15.20.2327.026; Thu, 10 Oct 2019 17:19:01 +0000 From: Alexei Starovoitov To: Peter Zijlstra , Song Liu CC: "linux-kernel@vger.kernel.org" , "bpf@vger.kernel.org" , "netdev@vger.kernel.org" , Kernel Team , "stable@vger.kernel.org" , Alexei Starovoitov , Daniel Borkmann Subject: Re: [PATCH bpf-next 2/2] bpf/stackmap: fix A-A deadlock in bpf_get_stack() Thread-Topic: [PATCH bpf-next 2/2] bpf/stackmap: fix A-A deadlock in bpf_get_stack() Thread-Index: AQHVfzKswn/pkqmThEy7QwA/cvFN/adTfF0AgACi1oA= Date: Thu, 10 Oct 2019 17:19:01 +0000 Message-ID: References: <20191010061916.198761-1-songliubraving@fb.com> <20191010061916.198761-3-songliubraving@fb.com> <20191010073608.GO2311@hirez.programming.kicks-ass.net> In-Reply-To: <20191010073608.GO2311@hirez.programming.kicks-ass.net> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-clientproxiedby: MWHPR19CA0001.namprd19.prod.outlook.com (2603:10b6:300:d4::11) To BYAPR15MB2501.namprd15.prod.outlook.com (2603:10b6:a02:88::11) x-ms-exchange-messagesentrepresentingtype: 1 x-originating-ip: [2620:10d:c090:180::f66f] x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: 99400205-3077-480d-10db-08d74da5f101 x-ms-traffictypediagnostic: BYAPR15MB2663: x-ms-exchange-transport-forked: True x-microsoft-antispam-prvs: x-ms-oob-tlc-oobclassifiers: OLM:175; x-forefront-prvs: 018632C080 x-forefront-antispam-report: SFV:NSPM;SFS:(10019020)(979002)(376002)(366004)(396003)(39860400002)(136003)(346002)(199004)(189003)(256004)(66556008)(66446008)(64756008)(478600001)(6512007)(8676002)(102836004)(446003)(54906003)(81156014)(11346002)(66476007)(66946007)(6486002)(486006)(81166006)(52116002)(305945005)(14444005)(2616005)(76176011)(46003)(7736002)(25786009)(476003)(6436002)(229853002)(31686004)(14454004)(186003)(6246003)(4326008)(99286004)(36756003)(2906002)(316002)(71200400001)(71190400001)(8936002)(86362001)(110136005)(5660300002)(6116002)(53546011)(31696002)(6506007)(386003)(6636002)(969003)(989001)(999001)(1009001)(1019001);DIR:OUT;SFP:1102;SCL:1;SRVR:BYAPR15MB2663;H:BYAPR15MB2501.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: JlOUHvbFeeg2+KRy49JZw8XQa/AWVhuCfJKMTIj6QfhcxnWnnD+kgjM0alnSJl4MZQdskhH9ke1muTcJi2uY+SIDuptoNzBRiiRLunhordFCcPrdUieQS7zpxV2AYVfQcC5mejVBuLMqJoEooUVv9sCIpZNH3cgPleF2e2DEcBhRSFfYbpruzZU/Kuy3X1YcVS96KGRCnn//GWQNnxWBz1th3Viy6IT2JKIVLBckmuuU83aHycGVKkE3rIMt+gRzVZ1MBiQYG3tb3aceAtS7IMwTAoJ4rpWyljyMJEmYBA4sXyrbpu4FzsGqvh5UBsJrdYhcucMpTrGzuZQVAEujDB9JGFsy4QF53K6csYv2Q4SkUrV/PtB0K/2fsAvH9Y/l1jiGQP8VsorOBQy/LVMKDPp61g7KT9xe4PsIjFew+Zg= Content-Type: text/plain; charset="utf-8" Content-ID: <886DEB1D6DD67342989EFADF24526243@namprd15.prod.outlook.com> Content-Transfer-Encoding: base64 MIME-Version: 1.0 X-MS-Exchange-CrossTenant-Network-Message-Id: 99400205-3077-480d-10db-08d74da5f101 X-MS-Exchange-CrossTenant-originalarrivaltime: 10 Oct 2019 17:19:01.6349 (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: qdu9LS4OBj4OODOhtT/UZd8oFp5Z1dOGidoEFv/jOnWqagubIfg7bH6jhl6scPX3 X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR15MB2663 X-OriginatorOrg: fb.com X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.95,1.0.8 definitions=2019-10-10_06:2019-10-10,2019-10-10 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 lowpriorityscore=0 mlxlogscore=999 clxscore=1011 spamscore=0 suspectscore=0 impostorscore=0 phishscore=0 bulkscore=0 priorityscore=1501 mlxscore=0 adultscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1908290000 definitions=main-1910100152 X-FB-Internal: deliver Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org T24gMTAvMTAvMTkgMTI6MzYgQU0sIFBldGVyIFppamxzdHJhIHdyb3RlOg0KPiBPbiBXZWQsIE9j dCAwOSwgMjAxOSBhdCAxMToxOToxNlBNIC0wNzAwLCBTb25nIExpdSB3cm90ZToNCj4+IGJwZiBz dGFja21hcCB3aXRoIGJ1aWxkLWlkIGxvb2t1cCAoQlBGX0ZfU1RBQ0tfQlVJTERfSUQpIGNhbiB0 cmlnZ2VyIEEtQQ0KPj4gZGVhZGxvY2sgb24gcnFfbG9jaygpOg0KPj4NCj4+IHJjdTogSU5GTzog cmN1X3NjaGVkIGRldGVjdGVkIHN0YWxscyBvbiBDUFVzL3Rhc2tzOg0KPj4gWy4uLl0NCj4+IENh bGwgVHJhY2U6DQo+PiAgIHRyeV90b193YWtlX3VwKzB4MWFkLzB4NTkwDQo+PiAgIHdha2VfdXBf cSsweDU0LzB4ODANCj4+ICAgcndzZW1fd2FrZSsweDhhLzB4YjANCj4+ICAgYnBmX2dldF9zdGFj aysweDEzYy8weDE1MA0KPj4gICBicGZfcHJvZ19mYmRhZjQyZWRlZDlmZTQ2X29uX2V2ZW50KzB4 NWUzLzB4MTAwMA0KPj4gICBicGZfb3ZlcmZsb3dfaGFuZGxlcisweDYwLzB4MTAwDQo+PiAgIF9f cGVyZl9ldmVudF9vdmVyZmxvdysweDRmLzB4ZjANCj4+ICAgcGVyZl9zd2V2ZW50X292ZXJmbG93 KzB4OTkvMHhjMA0KPj4gICBfX19wZXJmX3N3X2V2ZW50KzB4ZTcvMHgxMjANCj4+ICAgX19zY2hl ZHVsZSsweDQ3ZC8weDYyMA0KPj4gICBzY2hlZHVsZSsweDI5LzB4OTANCj4+ICAgZnV0ZXhfd2Fp dF9xdWV1ZV9tZSsweGI5LzB4MTEwDQo+PiAgIGZ1dGV4X3dhaXQrMHgxMzkvMHgyMzANCj4+ICAg ZG9fZnV0ZXgrMHgyYWMvMHhhNTANCj4+ICAgX194NjRfc3lzX2Z1dGV4KzB4MTNjLzB4MTgwDQo+ PiAgIGRvX3N5c2NhbGxfNjQrMHg0Mi8weDEwMA0KPj4gICBlbnRyeV9TWVNDQUxMXzY0X2FmdGVy X2h3ZnJhbWUrMHg0NC8weGE5DQo+Pg0KPiANCj4+IGRpZmYgLS1naXQgYS9rZXJuZWwvYnBmL3N0 YWNrbWFwLmMgYi9rZXJuZWwvYnBmL3N0YWNrbWFwLmMNCj4+IGluZGV4IDA1MjU4MGMzM2QyNi4u M2IyNzhmNmIwYzNlIDEwMDY0NA0KPj4gLS0tIGEva2VybmVsL2JwZi9zdGFja21hcC5jDQo+PiAr KysgYi9rZXJuZWwvYnBmL3N0YWNrbWFwLmMNCj4+IEBAIC0yODcsNyArMjg3LDcgQEAgc3RhdGlj IHZvaWQgc3RhY2tfbWFwX2dldF9idWlsZF9pZF9vZmZzZXQoc3RydWN0IGJwZl9zdGFja19idWls ZF9pZCAqaWRfb2ZmcywNCj4+ICAgCWJvb2wgaXJxX3dvcmtfYnVzeSA9IGZhbHNlOw0KPj4gICAJ c3RydWN0IHN0YWNrX21hcF9pcnFfd29yayAqd29yayA9IE5VTEw7DQo+Pg0KPj4gLQlpZiAoaW5f bm1pKCkpIHsNCj4+ICsJaWYgKGluX25taSgpIHx8IHRoaXNfcnFfaXNfbG9ja2VkKCkpIHsNCj4+ ICAgCQl3b3JrID0gdGhpc19jcHVfcHRyKCZ1cF9yZWFkX3dvcmspOw0KPj4gICAJCWlmICh3b3Jr LT5pcnFfd29yay5mbGFncyAmIElSUV9XT1JLX0JVU1kpDQo+PiAgIAkJCS8qIGNhbm5vdCBxdWV1 ZSBtb3JlIHVwX3JlYWQsIGZhbGxiYWNrICovDQo+IA0KPiBUaGlzIGlzIGhvcnJpZmljIGNyYXAu IEp1c3Qgc2F5IG5vIHRvIHRoYXQgZ2V0X2J1aWxkX2lkX29mZnNldCgpDQo+IHRyYWlud3JlY2su DQoNCnRoaXMgaXMgbm90IGEgaGVscGZ1bCBjb21tZW50Lg0KV2hhdCBpc3N1ZXMgZG8geW91IHNl ZSB3aXRoIHRoaXMgYXBwcm9hY2g/DQoNCg0KDQo=