From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from EUR03-DB5-obe.outbound.protection.outlook.com (mail-eopbgr40088.outbound.protection.outlook.com [40.107.4.88]) by sourceware.org (Postfix) with ESMTPS id E88EC383E803 for ; Fri, 15 May 2020 14:33:35 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org E88EC383E803 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=Wilco.Dijkstra@arm.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=armh.onmicrosoft.com; s=selector2-armh-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=3tQTDfqjEv4J36ongsPZmflXn6K5X+R0sCFu7GlCxv4=; b=8psN8hW1oXHyRNdolgt9A6B34Uk6KZ5Eru/HnXE5qeD7uNiRbmSApdqVpGzEpaEoq7+2jTFGzRZ8a6sSEfOIgdZMbI8isffHJirx78AT7OoQGGy0Xdjc8SF8w3J9ML2w4IFvkE/DBirWT5H4vjIC19/oZOxgCkPrptHPpt08N9g= Received: from AM6P194CA0009.EURP194.PROD.OUTLOOK.COM (2603:10a6:209:90::22) by VI1PR08MB3742.eurprd08.prod.outlook.com (2603:10a6:803:c3::16) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2979.30; Fri, 15 May 2020 14:33:34 +0000 Received: from AM5EUR03FT012.eop-EUR03.prod.protection.outlook.com (2603:10a6:209:90:cafe::c8) by AM6P194CA0009.outlook.office365.com (2603:10a6:209:90::22) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3000.20 via Frontend Transport; Fri, 15 May 2020 14:33:34 +0000 Authentication-Results: spf=pass (sender IP is 63.35.35.123) smtp.mailfrom=arm.com; sourceware.org; dkim=pass (signature was verified) header.d=armh.onmicrosoft.com; sourceware.org; dmarc=bestguesspass action=none header.from=arm.com; Received-SPF: Pass (protection.outlook.com: domain of arm.com designates 63.35.35.123 as permitted sender) receiver=protection.outlook.com; client-ip=63.35.35.123; helo=64aa7808-outbound-1.mta.getcheckrecipient.com; Received: from 64aa7808-outbound-1.mta.getcheckrecipient.com (63.35.35.123) by AM5EUR03FT012.mail.protection.outlook.com (10.152.16.161) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3000.19 via Frontend Transport; Fri, 15 May 2020 14:33:33 +0000 Received: ("Tessian outbound b3a67fbfbb1f:v54"); Fri, 15 May 2020 14:33:33 +0000 X-CheckRecipientChecked: true X-CR-MTA-CID: fbaaab5d8ac0e6ce X-CR-MTA-TID: 64aa7808 Received: from 99c7ff0e48fe.1 by 64aa7808-outbound-1.mta.getcheckrecipient.com id 2B6BE981-A3D4-4830-B3C3-77B500A41221.1; Fri, 15 May 2020 14:33:28 +0000 Received: from EUR04-HE1-obe.outbound.protection.outlook.com by 64aa7808-outbound-1.mta.getcheckrecipient.com with ESMTPS id 99c7ff0e48fe.1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384); Fri, 15 May 2020 14:33:28 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=bz5395Ps5gpN9BB4R4uk8CSYBuhYq3siRoJzUA2S2sWqZWrk4cfFyN7T8rHRzzrAIaOVt9QqZ4biMemlCQyMcPQN7U0vTgr5BRHtZw4AGUNquJapl0mpXOJ/Fbo6kXp7t3p2SXnnf9bIrHQN40La02fq2HeNV2gFzpmKgolJQjUwR7/AalkSTYRX+JGyh6IRupzT1DxPC4RPzx2KP1ZdE8CHDSsRY2OA4tY578+slfPvYwRKM5/mbx12eVCCWNeeV35ioH3Mhm0O2lU584lhMwab8oShMLy5iAjN6iSw6ryzKHqefeLa3s87pkV57JQOTPll5xf3YFlGkvM3koRGtQ== 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=3tQTDfqjEv4J36ongsPZmflXn6K5X+R0sCFu7GlCxv4=; b=ifgnbok7ug26Ype/IFL6MDpq/xbJz5qI8Drb10BrqDIn4Oc5zZ8IiJ/tkotRGbz8c5quSe+Z5EcSdbqoJoM5Icn4KrSbIWNPtQMfbJBCVoBDQ83FzJUXRBolan6tTUW081PSFN2kATX5Lsvo4DOWlQRG0DDK7vM+2hP66IvLTS4OC7zn85sMUCbQuJsgEtE7jN9htEKgKtALnDZV4tEwNPPfTsnHNIQkRS7vUdzYlDTPt/8lGLgzZc60vvN/f0croQNPNCCi8fKQOXiBxq689qaSjhGpqlCKup/kQZ/i7nHcsxkSriz1ErVAQIB30hrX9kjG/BvrDuiOoUxsuqFIfg== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=arm.com; dmarc=pass action=none header.from=arm.com; dkim=pass header.d=arm.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=armh.onmicrosoft.com; s=selector2-armh-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=3tQTDfqjEv4J36ongsPZmflXn6K5X+R0sCFu7GlCxv4=; b=8psN8hW1oXHyRNdolgt9A6B34Uk6KZ5Eru/HnXE5qeD7uNiRbmSApdqVpGzEpaEoq7+2jTFGzRZ8a6sSEfOIgdZMbI8isffHJirx78AT7OoQGGy0Xdjc8SF8w3J9ML2w4IFvkE/DBirWT5H4vjIC19/oZOxgCkPrptHPpt08N9g= Received: from DB8PR08MB5036.eurprd08.prod.outlook.com (2603:10a6:10:ed::20) by DB8PR08MB5452.eurprd08.prod.outlook.com (2603:10a6:10:111::10) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3000.20; Fri, 15 May 2020 14:33:26 +0000 Received: from DB8PR08MB5036.eurprd08.prod.outlook.com ([fe80::8dce:6db4:5358:200e]) by DB8PR08MB5036.eurprd08.prod.outlook.com ([fe80::8dce:6db4:5358:200e%3]) with mapi id 15.20.3000.022; Fri, 15 May 2020 14:33:26 +0000 From: Wilco Dijkstra To: "libc-alpha@sourceware.org" , "wangxu72@huawei.com" Subject: [PATCH] malloc: perturb mchunk returned from tcache like fast, small, large bin Thread-Topic: [PATCH] malloc: perturb mchunk returned from tcache like fast, small, large bin Thread-Index: AQHWKsNb6d2YjMzyyUSFQmVfZEYkqA== Date: Fri, 15 May 2020 14:33:26 +0000 Message-ID: Accept-Language: en-GB, en-US Content-Language: en-GB X-MS-Has-Attach: X-MS-TNEF-Correlator: Authentication-Results-Original: sourceware.org; dkim=none (message not signed) header.d=none;sourceware.org; dmarc=none action=none header.from=arm.com; x-originating-ip: [82.24.199.97] x-ms-publictraffictype: Email X-MS-Office365-Filtering-HT: Tenant X-MS-Office365-Filtering-Correlation-Id: babd3760-07e5-4a52-0726-08d7f8dcf260 x-ms-traffictypediagnostic: DB8PR08MB5452:|VI1PR08MB3742: X-Microsoft-Antispam-PRVS: x-checkrecipientrouted: true nodisclaimer: true x-ms-oob-tlc-oobclassifiers: OLM:9508;OLM:9508; x-forefront-prvs: 04041A2886 X-MS-Exchange-SenderADCheck: 1 X-Microsoft-Antispam-Untrusted: BCL:0; X-Microsoft-Antispam-Message-Info-Original: uo6BruvPlP4jr/OXD+T5ZQbBxUjsOKuP3ep7PprOs+c6wIy/RtOL4pArU+unIMZLF4zC/kkSCDEp+0ASBrHshz/xC+Cems18ZD+/GZUATI9N0i0NFNcH9pzk+XORTKW3/1JT4r7mGmbzv2/s+/skK2N+ryVcevqXxo49P6zGQntrV/Zt9mXQ5XnTUGmF3cmxz6Zq2pFcji0oO4ivb4hSDPcxxTzov4QAurGw+P4upHdDo4+5Pc5w5xg+QOJzoqcC3eQ1QK2SVquikrh6+IauQWF/rfONr2myMXcX2ef5oj8PQiqj5+0HQ+ptB4Fn8AKwvyHlf3tD/NzSYhHm4y6IobN4cEUiY3fecx5ArHAUMUd7wQM9npn9FB/nOt3ifzfPEOXwFkP+kq8+sIctqecxk9eMlvbTAnGJqAWkGsnwcR/mAAJRMLkJTNyn1Ls1Lna6 X-Forefront-Antispam-Report-Untrusted: CIP:255.255.255.255; CTRY:; LANG:en; SCL:1; SRV:; IPV:NLI; SFV:NSPM; H:DB8PR08MB5036.eurprd08.prod.outlook.com; PTR:; CAT:NONE; SFTY:; SFS:(4636009)(396003)(366004)(39860400002)(136003)(346002)(376002)(26005)(8676002)(66946007)(316002)(5660300002)(76116006)(4744005)(33656002)(64756008)(55016002)(478600001)(66476007)(66446008)(9686003)(66556008)(52536014)(2906002)(110136005)(7696005)(186003)(6506007)(71200400001)(86362001)(8936002); DIR:OUT; SFP:1101; x-ms-exchange-antispam-messagedata: UbQgUXwMYLvl7l9taajD6QxW4DIxuVO8pF1DDV6QCAeYPmEo0BJ/aJqv2xE+6avpQk/uF8bncO9auXKzm1a5BZEU4EOrb4cxSklTvKgGym+er25FAgKbrNqpaB4VHdhpE344V7R5oQLXfHlm62VpsiX4wcI1I5DddLdDUZDX0fqwUwAsIDMDWFwFvJgnCcAego87E5gZwUNE6hn4qK45YQXm7hOXIYTxqAFOW2DO7zgIu8JVLK5LFmjyVgdhwHhUVlEee62Jc2wmB3c/tyfvTnHoo/0J4X0nn7GwodcmkrkquXwFB4aFn+0ZwmLdQdvVTOEiN7JPoHHSihJsh4C/ApSiblcic9YAypaHWgpXr70TTeVeNK3fFjKF90kPS/mxAgQKAA8F8upyEFR1OydlBrZA+5btRGehwKdC4y2Dc9OcUYt0MiIvkeoR8iYB0p5BxzL6XNFa8m2R7G821KBsS+LlXJq37ikgZoIcv5I5kcM= x-ms-exchange-transport-forked: True Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-MS-Exchange-Transport-CrossTenantHeadersStamped: DB8PR08MB5452 Original-Authentication-Results: sourceware.org; dkim=none (message not signed) header.d=none; sourceware.org; dmarc=none action=none header.from=arm.com; X-EOPAttributedMessage: 0 X-MS-Exchange-Transport-CrossTenantHeadersStripped: AM5EUR03FT012.eop-EUR03.prod.protection.outlook.com X-Forefront-Antispam-Report: CIP:63.35.35.123; CTRY:IE; LANG:en; SCL:1; SRV:; IPV:CAL; SFV:NSPM; H:64aa7808-outbound-1.mta.getcheckrecipient.com; PTR:ec2-63-35-35-123.eu-west-1.compute.amazonaws.com; CAT:NONE; SFTY:; SFS:(4636009)(136003)(396003)(376002)(39860400002)(346002)(46966005)(55016002)(82310400002)(6506007)(36906005)(33656002)(81166007)(47076004)(110136005)(8676002)(86362001)(316002)(82740400003)(9686003)(70586007)(70206006)(8936002)(7696005)(336012)(4744005)(52536014)(356005)(186003)(26005)(5660300002)(2906002)(478600001); DIR:OUT; SFP:1101; X-MS-Office365-Filtering-Correlation-Id-Prvs: c9973c85-eded-4dcc-6f89-08d7f8dcedf1 X-Forefront-PRVS: 04041A2886 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-OriginatorOrg: arm.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 15 May 2020 14:33:33.8268 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: babd3760-07e5-4a52-0726-08d7f8dcf260 X-MS-Exchange-CrossTenant-Id: f34e5979-57d9-4aaa-ad4d-b122a662184d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=f34e5979-57d9-4aaa-ad4d-b122a662184d; Ip=[63.35.35.123]; Helo=[64aa7808-outbound-1.mta.getcheckrecipient.com] X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: VI1PR08MB3742 X-Spam-Status: No, score=-2.8 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, RCVD_IN_BARRACUDACENTRAL, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H2, SPF_HELO_PASS, SPF_PASS, TXREP, UNPARSEABLE_RELAY autolearn=no autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 15 May 2020 14:33:46 -0000 Hi Wang,=0A= =0A= I don't think tcache uses the odd perturb thingy at all, likely on purpose = since the goal=0A= of tcache is better performance. If you wanted additional safety, you would= disable=0A= tcache and switch on the additional malloc checks - maybe switching on such= checks=0A= should disable tcache automatically?=0A= =0A= Note overwriting blocks as soon as they are freed (rather than allocated) m= akes more=0A= sense since it catches many use-after-free errors. Overwriting allocated bl= ocks is not=0A= nearly as useful, especially if any internal pointers are cleared.=0A= =0A= Additionally any patch like this should have benchmark results so we know w= hat the=0A= impact will be on malloc performance. There are several benchmarks in bench= tests=0A= which might be good enough for this purpose.=0A= =0A= Cheers,=0A= Wilco=