From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from CAN01-YT3-obe.outbound.protection.outlook.com (mail-yt3can01on2117.outbound.protection.outlook.com [40.107.115.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1D08D2D879B for ; Mon, 21 Jul 2025 13:25:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.107.115.117 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753104326; cv=fail; b=CK6UGrAVIayTcjoBoGvH6IGI9y/FhpG26VSoucC+ukCYuyYZ6yAX4hgBS1oQhL7GNhvDFL2ghPs09ckrNbgSUAqIsbys+rLq3GzqLzDl4DBI82cKOEYE6GxMW7u8fraKN+8qFIjswMKG2B3nsr4zzx402jhQpMVcY3mwbyD3Hyo= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753104326; c=relaxed/simple; bh=qIpvh6ymfeueM77Pm5pOrDX4SjmJ3QP3vdsYgEJZsvY=; h=Message-ID:Date:Subject:To:Cc:References:From:In-Reply-To: Content-Type:MIME-Version; b=HdRYzVb9zCUPMfAvAyA84Tg3LPnb7gOZ6vMCRNBALH6v0IWpNK5eQxvAPmuot4refEajhXNKsi0qrz3Yk2HJEnnXK1XE0hXlyYuQNcyYDqW13bJD3j9UFppmFLhTpEp1SnUUue5eXkmLjNHH4TaaW8WB9y7X2AkAMJa+uJHS4ss= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=efficios.com; spf=pass smtp.mailfrom=efficios.com; dkim=pass (2048-bit key) header.d=efficios.com header.i=@efficios.com header.b=ibj58/KW; arc=fail smtp.client-ip=40.107.115.117 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=efficios.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=efficios.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=efficios.com header.i=@efficios.com header.b="ibj58/KW" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=yf/UDg4pbhLDIV3Dg9CB499+ZBtuSI+KDJBOijJZ4cFXw3cXPbYMd7e//IYq++wM3YxzB8R0TEF3BGoFb8AxIroJ6g5fj1FWmQxwX+/hU0DiryhphRGvNXd0amNNyumoj2oUaKXGUz+g/lJUo560bSMLwip0gJ3F8dgep81cwi99jLeqlHrRixK1lRB118i7I3euI81dKZ4ESEbD+4fJCTaJX6Tf3xyaPdUY/ly/BLdKHmJJiFpeMpKPYKcmmPq1K4etcfk6SAjhYJQ9lZzhvi16n5cDdJgflNYA+vuH1PZyFnPY4vAqz0+P/XO2U5JDCowxNIwNEtRSPXjz4tbS7g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=2zT2ia124LtF4SXT/nwyh2OFu01AsCgs53vbarTUffQ=; b=thjdCAwUDjxAz5vY4q/WJcfiYhh8TBU2yv+3kcMWImrSkGZNwtMIXemxwyMVypovBlo7XzJxuN7qAJgpR5P534LaxxFsKkbZskBq32cN3/6JO2ov5k1i/DrGstPTGXwD0YQuuRS224WTGVMA75KWpU8a6OWnBBmxhu7XbXuVFsY48ODJJ7mC7oON3Jhp9EOL9mvswsC78BzcilMQx8TJ3Zuvj1+XN81Qsv293WJf3aBQdcL3eeqQVqhkVOmhx9NHi9QxZZG1Fn/vZZNXJFadvIDFE+fbOXKbmd5WbJl2UOQzNWuId5LM1XseGcXP7TfIe1j9myK8EjhREvw6qR+qZQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=efficios.com; dmarc=pass action=none header.from=efficios.com; dkim=pass header.d=efficios.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=efficios.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=2zT2ia124LtF4SXT/nwyh2OFu01AsCgs53vbarTUffQ=; b=ibj58/KWe9w4KJJePQopMJMSXwCf3uzoPe8MsqsTV2FRO0BQhYi9698Jwqm/IiVHwKA64WcvLtqPauUe4Ogekh+2e/lwHFw2yM0xiML2YX+KoEeR+SD7S16Yi7rb1n6aC1Qxf91nkVsGBw4Gf/Hwx208Vy+pPfPjM8LNDYqTPaK445T8TFz+bDU1gVx24g1trEXuQvPSlCIHt5rlYplil7j2WE+93kRS+d5dlJnb9AfX7o3HukP8hJpnQqT0i9jYidtu5AsCTYBRUnDwpnBJcmF9k2Z/IstP4lv86l7KA06zGl0dpNs2DqAu4GSRDELKeV4Pl1ZBs3HDyE1Y/5ncMg== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=efficios.com; Received: from YT2PR01MB9175.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:b01:be::5) by QB1PPF9A4BD32AB.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:c08::26a) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8943.30; Mon, 21 Jul 2025 13:25:18 +0000 Received: from YT2PR01MB9175.CANPRD01.PROD.OUTLOOK.COM ([fe80::50f1:2e3f:a5dd:5b4]) by YT2PR01MB9175.CANPRD01.PROD.OUTLOOK.COM ([fe80::50f1:2e3f:a5dd:5b4%3]) with mapi id 15.20.8943.029; Mon, 21 Jul 2025 13:25:18 +0000 Message-ID: <6e737bd5-1167-4cc8-96c3-abc3d3598d2d@efficios.com> Date: Mon, 21 Jul 2025 09:25:15 -0400 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v7 3/4] rseq: Make rseq work with protection keys To: Dmitry Vyukov , dave.hansen@linux.intel.com Cc: "Paul E. McKenney" , x86@kernel.org, linux-kernel@vger.kernel.org, Ingo Molnar , =?UTF-8?Q?Stephen_R=C3=B6ttger?= , peterz@infradead.org, boqun.feng@gmail.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, aruna.ramakrishna@oracle.com, elver@google.com References: <138c29bd5f5a0a22270c9384ecc721c40b7d8fbd.1747817128.git.dvyukov@google.com> From: Mathieu Desnoyers Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: YQBPR0101CA0104.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:c01:5::7) To YT2PR01MB9175.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:b01:be::5) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: YT2PR01MB9175:EE_|QB1PPF9A4BD32AB:EE_ X-MS-Office365-Filtering-Correlation-Id: 0a872e2c-e764-45cc-3d18-08ddc85a0923 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|366016|7416014|376014|7053199007; X-Microsoft-Antispam-Message-Info: =?utf-8?B?TWlnMzVMZnFoOHNjR3JtL1RRNjBiYVM3Q0RyYU0rNlZtVktEZVo1WlRMczlJ?= =?utf-8?B?TloyRGJkL1hpUVpNekZNbmVvZGNQdkVPZTBMWXFZa1QwekFidFBzYUFzRDBK?= =?utf-8?B?Znh2QXhIUHcvbXViQkc3RDdaZTZzM0hjL3dXN3hZaGduREgyMW1xU21JSG9l?= =?utf-8?B?SkFEbzFNWHAwcHRSdFNDSXV6QTl4VWpMUldtU003NzN3cGlIUGJhQVZJSlUw?= =?utf-8?B?UVFRd3RGSG5tWjZLbmxhOFNieTA3a3R1ZWFTN1JvQWx6dG9yN2Yra2htRHpF?= =?utf-8?B?OEpQRk1sSzdDakFna1FESGxCRi9DOE1ZVDN6R0ZPY08yVDhzaCtOalV5aHJn?= =?utf-8?B?TjBMTThWL09qbkFnR095djY0WHZ0N00zT2lJaDdta1p2MVVGSUxSZEYybU5W?= =?utf-8?B?VzhvQTBVUTlURk4yQjB3NGFlMWx2OUNPbFdSanpKVHFsUHNUL3Q5VnJPV1J2?= =?utf-8?B?T24rbHFITllyTk9BNEZXem4yaGxvemdrdW5vZmU3Q1BiRmlIei9vKzNVd1dr?= =?utf-8?B?QjRldTV6NzZaR0szMTBPVXdIZHZ1K25nOUtiR2Y4UkV3M2RLb2h6MDAvdlg0?= =?utf-8?B?NksxSkNzLzNhOElQdUZLazB6ODREdUpFQmh5M1hNc1l4REFNdExFZ3d3NHFB?= =?utf-8?B?b214WXNDeXZPTWR1VWMvV3lhUURqQ1BjRi9UK21HakhGd0JBUWdhQWdWUFUv?= =?utf-8?B?cHZudUJGQzBkcERhNzZZejh5bG8xck51K05BMVk5dEZDWGFvbmRnbkVtT3A1?= =?utf-8?B?Q05RZUZnNHZhQ3NpY2V0WkpNNFhRcDdiK1htRExFbmNPdUhoV1NGK1dOZlN2?= =?utf-8?B?TEx3aVhIekZQQVpHcWZPbDdDUVl3YmpIQW8rMC95ZW5iUUh4OU8yUjhQcWhL?= =?utf-8?B?SXF6SDk0b3pXdnFwYkJwUXZOSXdqQzY3bEhROUVmZTdWVnBWcWFUMnhmWU8v?= =?utf-8?B?d2daZjg1QUpaN0NvY2tvUE50eGdBNk1ZdDl3WlpidDFVSDFkcWdneW5uZU16?= =?utf-8?B?T2wxbDlTZW13NFBITCtxdDdIcDNwbnpaZ25mbHl3alhBYmVqd2NWa2RWdnVH?= =?utf-8?B?NHZuZ0dMcFRVVWxlRlJZT1BKaDhjK3ZpWjRFSC9kcGQvMTJ4b1Uva09JMExJ?= =?utf-8?B?MFBkY2hzU1pjQ3R1czJJRE82RG5jL2ZlQUh5YWozU2xFUUJ5ZWh2Qk8rUkVT?= =?utf-8?B?OGZhdmJTbk50WndpUjcrcnI1THRNTk5KeWg3ek1XblFvaG5qRDFrcDF1dElu?= =?utf-8?B?QmhSQU9pNEQxS1hHZ1lMcXFtV01ubk1XcjhPL3VVaVpVQUdOU2QvQmx1eHFO?= =?utf-8?B?enQ2WllUVGZGNjRUL2dsMUkxZDFiQmhZK0NOYmdaRFVudE5RNk5LVHZHTnNh?= =?utf-8?B?aVpCbUpqa083dmhXM0ZocWdMaEM3dUQxRTJhNVk0aDhWaDd5ZEpiYTN4Vlhr?= =?utf-8?B?RXgrbnpZd29wVjNYMkwyOWluQytaR3dGd0ZMTHg2Y0prTXdkcXBQWjBPemth?= =?utf-8?B?bTI3OEF1WERmUGlTVUJxbzNJRnAvUndTRGkzS0p2V3pkbEJLdmVPRCt0ejZM?= =?utf-8?B?ZThPWXYwcDJpOVFWWEtkcVBZaExtckZ2L29ZUXVTYkxUZ3VLYVdrUlhaSDVH?= =?utf-8?B?clIzN241VHh6M0xWR3phTCtmc2taR1pBeFZkTUlURmVEcE8vNi9GWmNvK0VT?= =?utf-8?B?NUhTUFFBSkFrUitRcFI3eWIxNkduTG5WUnU1eGNHam52MGIzVmRIdm10eEZU?= =?utf-8?B?WUs4UGExVXZFa3VTMTh1cHY4VC9PUHpqcnE4cXRtZTRxRXFnaFh6dGJMV213?= =?utf-8?Q?AajVh8POGl+KGdDMZErE3Hj4z6vAiYiZGW87g=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:YT2PR01MB9175.CANPRD01.PROD.OUTLOOK.COM;PTR:;CAT:NONE;SFS:(13230040)(1800799024)(366016)(7416014)(376014)(7053199007);DIR:OUT;SFP:1102; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?TkdNVmVGVjhGdXR4d0QxbkpQbkxMYmpUc3hNTWtLVHpIRCt2VVd1cTNuYlZU?= =?utf-8?B?c1FKVUlLaHZQMTd6aE5rNzFPdjM1ZldBeEtDMXBpckpjNW02QzZZUTJubVha?= =?utf-8?B?aDZYQzEvaEUrV3owa3lXTGR0b1l3Q2ZLRjVaZDRHMXp4NDVtNS9zbXNqZi9W?= =?utf-8?B?RG8wL05RdlFEQ0w4enBRaG1MZ29wUkZnU3lOTmM4OEowU1FZNUM1blB3dDZh?= =?utf-8?B?UWhaVlRoWk1FSTdKc080NVVIcnJwa3g3RVZUNXMvQ09zenQ3aTBENllEUDY2?= =?utf-8?B?YUR3WVp5OXcxcHhPL0x0UHRmYjFPdHlNRHAwYVBwK2JRT3ArLzFkUnJOSWMz?= =?utf-8?B?T2E3NnVsSXVzclhiVUZNWE1vN1BwaEg4VklacFpBV0hUaFFRakpwVTZVL0tr?= =?utf-8?B?MGlIQ2hjL0pqREQrVzNMMFdndHkreGtDK09rRlYwdTJkSmFESHZqSm1vMGF1?= =?utf-8?B?bmZFQ1ZwWFhlOGY1WVZnWVlBaVpZYWlxUC9OT09SdGNTL1o2U2hLNVpacXRM?= =?utf-8?B?dkJsbWhianpjZ0I3Y1o2UUxyRzNaOWZwM2dQUnB2NFlzUmRmT0wrbjhhbEFi?= =?utf-8?B?ZHhmMkNwSGpzMDk5VHlLSnpyREtoT1BPek9hVHEvSkJoRFk4NjNpR1Z3Vkk0?= =?utf-8?B?REFzbmFjZksra0wwbmkzYlIxem5DR0g4UnZBQ1g2bHBkeE1SMnlMWTFsejQy?= =?utf-8?B?RXQrVFpxMnFodXdCZk9DWFJtQVoxZlZ0YTN6RmJHOTZ1NncrODI1c2p2eWlh?= =?utf-8?B?VmFmNWdvWENjMzJhd3dIUWk2SVJVOWx4YmpaV1dpSERlczlkZGRRL3VOR3JQ?= =?utf-8?B?SkFzTzZNbk0rWHN0YlVLWHZrSGQ5S0Z6ejgyM094VnRvSVBRdTRzNGtvUTRu?= =?utf-8?B?WCtNRmRtY2lmajZWcFhFeWs2SDFJYUVxaXhVWGFpeWdrdHVYcFlRMHo1SWhj?= =?utf-8?B?N1cvZUg0V3hVcnErS2lEOSs0K2QweXRWd21aV3IzSlJkUU4yVnc0K1lESE9C?= =?utf-8?B?QW1XQ1R5bmlHUVRxWHZYd1ZOUkt2eVNldUpITHNMN3NEdHlld0lNWUhBVy85?= =?utf-8?B?UVdrbGR1bktSemRXRVV0U0I3c243V01OWmZKN0k4SXZ3bUN6QWxhdzJzbmpJ?= =?utf-8?B?MVEwRzM4NUxwWnpVYUdIUENZYU1BUHhGTUxsNHFkMU1GWjVwQWdRUm1ZbHkz?= =?utf-8?B?T21wMjFTUzdhTmxiSmw4NGYzVzR6RGErRnpEZk5LZUUyNkVBV3pqUk95TXdt?= =?utf-8?B?NTlmWnhCSG9XRnBlRXlUb09RTmVTM1FHcFFKU0hwMERDd2tMUmU4dFRSNWxW?= =?utf-8?B?a3lKT21BbmY0NVRnNWxxTUV3WTJXcE5yY2NpZlBKc1BXRGR1U003cllhV3gr?= =?utf-8?B?MjhTeWdvU3Y2RnhXd3VQUGlKemFWQjRPZXNQWVpMWWtaaWc4YjlBbXp1bng4?= =?utf-8?B?Z1RySm1jREd2SGdjLzZUWG5qK3RyWWg5VHZxSG9SdmI4a0tRR1VyWm1kYzl6?= =?utf-8?B?RFQ1OXNleWh2d0F4UzB3SVpEQmt3SktGL0drWnJUK0RWeTlNV3FUcHByejBi?= =?utf-8?B?MnV5UVcxZlZjOWE2WHAySktNWW5CVk9HbzE3RG5NcG5YbVlmdmw0N3VvWTg4?= =?utf-8?B?OW04QW1wbGhibjJwcXJhUFRVUm9YNmZ5Mk80bERMRWEvTmRjTWdhZ2JoZ0ph?= =?utf-8?B?S01XRDZ2c2dXYXpwKzIwcVZEUTMvRmJsQnJGNUlDY1hIODVUU0haVGdmNnBw?= =?utf-8?B?a0YrZUNPZDA1S3hNeld5QzNBQ0IvdE8ySVVHTjhCQjhiNElTdHZwN1lZOTFU?= =?utf-8?B?MXVlaXY0b3dZbk50ckk4NFFyclAyeXJwK3dKeDFScU1XSGtFbUZveldRUE0v?= =?utf-8?B?L2VkRWI2cCtYU05lNmtYSEdJcFJ5T21ZUlZzUVFiVG5HeHJvY2xUN3lvS3M0?= =?utf-8?B?YnFmU1BuclZ1a1JGcm1JOTdSSFkwd05DaWRISGd5alEwS3l1dDdyMlNnSXo2?= =?utf-8?B?emVjVWdvaERiSVl5b0tsT2tMdFppQTFiSWg5ZG5mbzB4cXVuTGpYVkFGN3RB?= =?utf-8?B?K3RYdUdDU3JUbDBDcWJBdEJXU28vV1l5QXJ0cG5XV3BRZEtEVHJsQTkrbFR6?= =?utf-8?B?U2VrY1phVnY3RHgvcWE4dFpwUWlWQWpYaFFEN2VlUzBWMS9oYjlHa29jWFBJ?= =?utf-8?Q?aiCWZYAjV+x4g5+ZDpyJKXs=3D?= X-OriginatorOrg: efficios.com X-MS-Exchange-CrossTenant-Network-Message-Id: 0a872e2c-e764-45cc-3d18-08ddc85a0923 X-MS-Exchange-CrossTenant-AuthSource: YT2PR01MB9175.CANPRD01.PROD.OUTLOOK.COM X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 21 Jul 2025 13:25:18.4601 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 4f278736-4ab6-415c-957e-1f55336bd31e X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: eXRz16jZr1FldxbqQDg6A5RkVD5aM+sUE930zxaSUF4ucHkrigdxxtecSunZTa0PZ9e8HwxO4XNVSqkGF3VT4a8ophz8S8Tyssd6J5q0tmo= X-MS-Exchange-Transport-CrossTenantHeadersStamped: QB1PPF9A4BD32AB On 2025-07-18 05:01, Dmitry Vyukov wrote: > On Tue, 24 Jun 2025 at 11:17, Dmitry Vyukov wrote: >>>> If an application registers rseq, and ever switches to another pkey >>>> protection (such that the rseq becomes inaccessible), then any >>>> context switch will cause failure in __rseq_handle_notify_resume() >>>> attempting to read/write struct rseq and/or rseq_cs. Since context >>>> switches are asynchronous and are outside of the application control >>>> (not part of the restricted code scope), temporarily switch to >>>> pkey value that allows access to the 0 (default) PKEY. >>>> >>>> Signed-off-by: Dmitry Vyukov >>>> Reviewed-by: Mathieu Desnoyers >>>> Cc: Peter Zijlstra >>>> Cc: "Paul E. McKenney" >>>> Cc: Boqun Feng >>>> Cc: Thomas Gleixner >>>> Cc: Ingo Molnar >>>> Cc: Borislav Petkov >>>> Cc: Dave Hansen >>>> Cc: "H. Peter Anvin" >>>> Cc: Aruna Ramakrishna >>>> Cc: x86@kernel.org >>>> Cc: linux-kernel@vger.kernel.org >>>> Fixes: d7822b1e24f2 ("rseq: Introduce restartable sequences system call") >>> >>> Dave, can you please ack this patch? Ingo said he was waiting for your >>> review before taking this to -tip. >> >> Are there any remaining concerns with this series? If not, Thomas, >> Ingo, can you please take this to -tip tree? > > Gentle ping. What needs to happen for this series to be merged? This series looks OK from my perspective. I think the last piece that was missing was to get a review from Dave Hansen. Dave ? Thanks, Mathieu > > >>>> --- >>>> Changes in v7: >>>> - Added Mathieu's Reviewed-by >>>> >>>> Changes in v6: >>>> - Added a comment to struct rseq with MPK rules >>>> >>>> Changes in v4: >>>> - Added Fixes tag >>>> >>>> Changes in v3: >>>> - simplify control flow to always enable access to 0 pkey >>>> >>>> Changes in v2: >>>> - fixed typos and reworded the comment >>>> --- >>>> include/uapi/linux/rseq.h | 4 ++++ >>>> kernel/rseq.c | 11 +++++++++++ >>>> 2 files changed, 15 insertions(+) >>>> >>>> diff --git a/include/uapi/linux/rseq.h b/include/uapi/linux/rseq.h >>>> index c233aae5eac90..019fd248cf749 100644 >>>> --- a/include/uapi/linux/rseq.h >>>> +++ b/include/uapi/linux/rseq.h >>>> @@ -58,6 +58,10 @@ struct rseq_cs { >>>> * contained within a single cache-line. >>>> * >>>> * A single struct rseq per thread is allowed. >>>> + * >>>> + * If struct rseq or struct rseq_cs is used with Memory Protection Keys, >>>> + * then the assigned pkey should either be accessible whenever these structs >>>> + * are registered/installed, or they should be protected with pkey 0. >>>> */ >>>> struct rseq { >>>> /* >>>> diff --git a/kernel/rseq.c b/kernel/rseq.c >>>> index b7a1ec327e811..88fc8cb789b3b 100644 >>>> --- a/kernel/rseq.c >>>> +++ b/kernel/rseq.c >>>> @@ -10,6 +10,7 @@ >>>> >>>> #include >>>> #include >>>> +#include >>>> #include >>>> #include >>>> #include >>>> @@ -424,11 +425,19 @@ static int rseq_ip_fixup(struct pt_regs *regs) >>>> void __rseq_handle_notify_resume(struct ksignal *ksig, struct pt_regs *regs) >>>> { >>>> struct task_struct *t = current; >>>> + pkey_reg_t saved_pkey; >>>> int ret, sig; >>>> >>>> if (unlikely(t->flags & PF_EXITING)) >>>> return; >>>> >>>> + /* >>>> + * Enable access to the default (0) pkey in case the thread has >>>> + * currently disabled access to it and struct rseq/rseq_cs has >>>> + * 0 pkey assigned (the only supported value for now). >>>> + */ >>>> + saved_pkey = enable_zero_pkey_val(); >>>> + >>>> /* >>>> * regs is NULL if and only if the caller is in a syscall path. Skip >>>> * fixup and leave rseq_cs as is so that rseq_sycall() will detect and >>>> @@ -441,9 +450,11 @@ void __rseq_handle_notify_resume(struct ksignal *ksig, struct pt_regs *regs) >>>> } >>>> if (unlikely(rseq_update_cpu_node_id(t))) >>>> goto error; >>>> + write_pkey_val(saved_pkey); >>>> return; >>>> >>>> error: >>>> + write_pkey_val(saved_pkey); >>>> sig = ksig ? ksig->sig : 0; >>>> force_sigsegv(sig); >>>> } >>>> -- >>>> 2.49.0.1143.g0be31eac6b-goog >>>> -- Mathieu Desnoyers EfficiOS Inc. https://www.efficios.com