From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=pass header.oldest-pass=0 smtp.remote-ip=205.220.165.32 ARC-Seal: i=2; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=pass; t=1793357642; b=29MJ0WHT7c3iv5N2GCQMPEpfyfj3K1O+WDBVzAu8zDROXGHc4NUUmLwauggjk+oJj64Q 7plpQ9oID1LS3k+ITWg9Z8gj6wrtojtrcoyZZiqBSh0z03jKgu6sG+k5J/u/jYlGPVW0i jrQen7/O13z8TiDmdEM6XY+BtnSg0Xwx3F9ljTGKVHQRI0TZYtEPugs8P5aqq3Rpsnzr7 Xk30JbVFves2uVHCUCKwd4utVzxu+7xHVl4FdfhqZuVyETsIww35FDGeXETL2eOpUoNiW 24xfkQ7P4kCgVo5E2cBLeaR71M4HLFDJ8NXYGLD0E5eAF94X8WyXhVLMitCdn0hPSDw== ARC-Message-Signature: i=2; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793357642; h=DMARC-Filter:Received:DKIM-Signature:Received:Received:Received: DKIM-Signature:Received:Received:Message-ID:Date:Subject:To:Cc: References:Content-Language:From:In-Reply-To:Content-Type: Content-Transfer-Encoding:X-ClientProxiedBy:MIME-Version: X-MS-TrafficTypeDiagnostic:X-MS-PublicTrafficType:client-request-id: request-id:X-MS-Office365-Filtering-Correlation-Id: X-MS-Exchange-SenderADCheck:X-MS-Exchange-AntiSpam-Relay: X-Microsoft-Antispam:X-Microsoft-Antispam-Message-Info: X-Forefront-Antispam-Report: X-MS-Exchange-AntiSpam-MessageData-ChunkCount: X-MS-Exchange-AntiSpam-MessageData-0:X-Exchange-RoutingPolicyChecked: X-MS-Exchange-AntiSpam-ExternalHop-MessageData-ChunkCount: X-MS-Exchange-AntiSpam-ExternalHop-MessageData-0:X-OriginatorOrg: X-MS-Exchange-CrossTenant-Network-Message-Id: X-MS-Exchange-CrossTenant-AuthSource:X-MS-Exchange-CrossTenant-AuthAs: X-MS-Exchange-CrossTenant-OriginalArrivalTime: X-MS-Exchange-CrossTenant-FromEntityHeader: X-MS-Exchange-CrossTenant-Id:X-MS-Exchange-CrossTenant-MailboxType: X-MS-Exchange-CrossTenant-UserPrincipalName: X-MS-Exchange-Transport-CrossTenantHeadersStamped: X-Proofpoint-Virus-Version:X-Proofpoint-Spam-Details: X-Proofpoint-Spam-Details-Enc:X-Authority-Analysis:X-Proofpoint-GUID: X-Proofpoint-Spam-Info:X-Proofpoint-ORIG-GUID; bh=0m1KRfxR8XKHPUhFuiozlOI1J4rQWDyWGyGE65GD+cA=; b=H30DbBbQ+gvR9z/V5O2MBsPallSYmDuNKwBP066aKoxlT6057ru/Zlf2wpQNnDzAlRFY Ing91oKo7gq2PmZLtRzUWuma7rv+RYCB9P0MLVBCBQXmmMgPmDq4tpVRNLN6B28ZHe9D6 XF5E46CCPWJ0j+2+ID4mn3uXdoELokg4G/39uMH0oEsfdCe3Gm09lz10pF3jwqupE0zKR 43lrcMXqelNV7Y5feMb1ggTLdJz5YozHS8uiRGOTwK//cmyqBaGuAjbs3Cq2442N5hulE eYO33zQOUAn1azwebe0NCCEKmZADwRpEc8sPSPGtHqR2vodn8x3kB6TBfOqoKANVMHQ== ARC-Authentication-Results: i=2; smtp.subspace.kernel.org; dmarc=pass header.from=oracle.com; spf=pass smtp.mailfrom=oracle.com; dkim=pass header.d=oracle.com header.i=@oracle.com header.a=rsa-sha256 header.s=corp-2025-04-25 header.b=WT9rbvon; dkim=pass header.d=oracle.onmicrosoft.com header.i=@oracle.onmicrosoft.com header.a=rsa-sha256 header.s=selector2-oracle-onmicrosoft-com header.b=m9EFnzpY; arc=pass header.oldest-pass=0 smtp.remote-ip=205.220.165.32 Received: from mx0a-00069f02.pphosted.com (mx0a-00069f02.pphosted.com [205.220.165.32]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E1E77606C6DC; Fri, 30 Oct 2026 10:54:01 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org E1E77606C6DC Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=oracle.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=oracle.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=oracle.com header.i=@oracle.com header.a=rsa-sha256 header.s=corp-2025-04-25 header.b=WT9rbvon; dkim=pass (1024-bit key, unprotected) header.d=oracle.onmicrosoft.com header.i=@oracle.onmicrosoft.com header.a=rsa-sha256 header.s=selector2-oracle-onmicrosoft-com header.b=m9EFnzpY Received: from pps.filterd (m0246627.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 69U2tV8R679165; Fri, 30 Oct 2026 10:53:43 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=cc :content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s= corp-2025-04-25; bh=0m1KRfxR8XKHPUhFuiozlOI1J4rQWDyWGyGE65GD+cA=; b= WT9rbvonA1zlSX6M5urVtmuwbYzk9Wsf3n4fGeYy/Thw1i3Qt4nEuGNKoh5RUqJd RDc/t6aRZsBkhyxhCVI7heC9d3XuMutCwaGrO87soIeatArNMsNnJL8YnCmXF7Kl EUVveQTXxU+rU2mWbFtQ2ot2jXUv88e9GkxUGHoDCHsKdyR3J3biQl6XGFK2h8Gt eMMrmLH2Yf9ND9UlY5cQ3qvtFI37tBr3/s9zHeEXTNhUuDITOmgVjKfge8a3an0p jkME7j4PVQhuG8doLYNMz/TPJ254pc2EmWX5bkyER7Rrn6mTBp+Lx7wAKcbmczZ6 aXhGVoiyPA1PlHh/33ofwA== Received: from phxpaimrmta02.imrmtpd1.prodappphxaev1.oraclevcn.com (phxpaimrmta02.appoci.oracle.com [147.154.114.232]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 4hme5prmdr-1 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=OK); Fri, 30 Oct 2026 10:53:43 +0000 (GMT) Received: from pps.filterd (phxpaimrmta02.imrmtpd1.prodappphxaev1.oraclevcn.com [127.0.0.1]) by phxpaimrmta02.imrmtpd1.prodappphxaev1.oraclevcn.com (8.18.1.11/8.18.1.11) with ESMTP id 69UAnu3G3525438; Fri, 30 Oct 2026 10:53:43 GMT Received: from ph0pr06cu001.outbound.protection.outlook.com (mail-westus3azon11011029.outbound.protection.outlook.com [40.107.208.29]) by phxpaimrmta02.imrmtpd1.prodappphxaev1.oraclevcn.com (PPS) with ESMTPS id 4hmsu4r3b8-1 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=FAIL); Fri, 30 Oct 2026 10:53:43 +0000 (GMT) ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=gf7V0KFO2AF54dchA0qZsNyhg2bTit27k2srrDp7Vh4fJalvrde0Jo6605YpXlJ6hp4pavqXqIyewQy0Nr8bYqmJ7uMsAQdtfKXnr6eTdPS08n+/xrEOFWq/wNoNC125ZWzDgsQKx9SqRIBSj9a1t3fJfdDivHo8ERVu3eNyc0V/XVD3nW3uX+IPQ+BmJzOxbCiGYJlINL/5tkNnu9x5Mh3DMh2qPwkOqZjGLryBkbNitJ4/MEm/7uDe4zssxbnVSR2uQTTHKb8dS66D0ZCJFkLOwDgtrwl7PatYOHyp5LlSFcKqphwwAWxTNcS6Yi5n5q5p1rGbswz1vRNtApqZsw== 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=0m1KRfxR8XKHPUhFuiozlOI1J4rQWDyWGyGE65GD+cA=; b=F9M4CKDYD5ns69+76f4DW5Wb7ws0BWAcQcpv2zckfCUGUblTHIh15c1yiPR5HK/Aq0/RxQxUhlfxcG8RNDdCUHf1qZAy5kbeE1IW1sn79+hK9NuutCeZXw+UhnqVejtb+Lfq7M/tmEKfKgT4d8DJoMIPvKTKOsfxcTuv2wOufODB+bi1zTbu6NaK6oQLjCUoXd/QaO1BeMsovmjgMHYRCZjugpIorARrlT2vHCOiooQh+Fd5o6FSVpAVGExOGUBFJLZ0m3lPRFJy7ERMd958uT+9nQVK6j8Zm2LmR+hBwXvPH6v6KqTkVsNg2OxEON8aSazEMCJN/hu1clphSD0ZVA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=oracle.com; dmarc=pass action=none header.from=oracle.com; dkim=pass header.d=oracle.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.onmicrosoft.com; s=selector2-oracle-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=0m1KRfxR8XKHPUhFuiozlOI1J4rQWDyWGyGE65GD+cA=; b=m9EFnzpY0wSf/EpZxuxaTNBSDKnhuPYo/o5c1rUq0ndbiWgGgCwaY15Sp2TuJeFpC4aXp9rhqirN/cKRr7+zqElUNIYD8L0F2Ga8JSl3f/YCRlr660acXmpkHyAbwhFztb+gVYjQYw9YDuW4pHIxlAqO8uZOVixzDvPiC/ExsOY= Authentication-Results: mx.microsoft.com 1; dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=oracle.com; Received: from CHAPR10MB997722.namprd10.prod.outlook.com (2603:10b6:610:2f3::10) by MW4PR10MB6464.namprd10.prod.outlook.com with HTTP via P2P; Fri, 30 Oct 2026 10:53:40 +0000 Received: from CHAPR10MB997722.namprd10.prod.outlook.com ([fe80::d6fa:c744:373e:9f4f]) by CHAPR10MB997722.namprd10.prod.outlook.com ([fe80::d6fa:c744:373e:9f4f%4]) with mapi id 15.21.0569.009; Fri, 30 Oct 2026 10:53:40 +0000 Message-ID: <7de3d0dd-f504-4c8f-8358-80634a2edd6b@oracle.com> Date: Fri, 30 Oct 2026 10:53:33 +0000 Subject: Re: [PATCH] dax/pmem: fix unaligned compound devmap initialization To: Muchun Song Cc: Muchun Song , Andrew Morton , Ritesh Harjani , stable@vger.kernel.org, nvdimm@lists.linux.dev, Dan Williams , linux-cxl@vger.kernel.org, linux-kernel@vger.kernel.org, Vishal Verma , Dave Jiang , Alison Schofield References: <20261016054914.2601510-1-songmuchun@bytedance.com> <31c89da1-6d3f-4a42-b6bb-2b8f8170eed6@oracle.com> Content-Language: en-US From: Joao Martins In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-ClientProxiedBy: LO4P123CA0435.GBRP123.PROD.OUTLOOK.COM (2603:10a6:600:1a9::8) To CHAPR10MB997722.namprd10.prod.outlook.com (2603:10b6:610:2f3::10) X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 X-MS-TrafficTypeDiagnostic: CHAPR10MB997722:EE_|MW4PR10MB6464:EE_ X-MS-PublicTrafficType: Email client-request-id: 2820c82c-ff24-4467-9fb2-ceea1e9746f6 request-id: 481f4185-3dab-4abc-4f53-08df36740e83 X-MS-Office365-Filtering-Correlation-Id: 481f4185-3dab-4abc-4f53-08df36740e83 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|7416014|366016|1800799024|23010399003|6133799003|18002099003|22082099003|56012099006|4143699003|261022105027099003|261026140227099003|10067099003|261022075727099003|261021121427099003|261021135927099003|261028144727099003|261026121527099003; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:;PTR:;CAT:NONE;SFS:(13230040)(376014)(7416014)(366016)(1800799024)(23010399003)(6133799003)(18002099003)(22082099003)(56012099006)(4143699003)(261022105027099003)(261026140227099003)(10067099003)(261022075727099003)(261021121427099003)(261021135927099003)(261028144727099003)(261026121527099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?SkVTdjNkK1g1YW5vb0Z1NXBldi9DeXJOMTgyNkZGTlBJek9DODYwd3V6bG1w?= =?utf-8?B?aWwyTXdYRmNiWWJoLzcyMk1FU1krWjljcFI2cEVlWXlRZ1huK1NPMEpnSzE5?= =?utf-8?B?cDY0UjJHbXlSWFZZQzVUcnlsNzVCUWdOajljUWRRc0VnN3JIcFhFTytseitD?= =?utf-8?B?cnBWQTNwZE5CQlZ2czNTVXhQVTFFR1VmaE9xTzFaZTRrZnZua004ZnRPcXRB?= =?utf-8?B?cHpWVCsvSUpVRGZmS29Ka1RDS1VZZkJDd21QY1YwQytDMVZlRWsrYjJxdGFQ?= =?utf-8?B?V1l4L21lVWgzOGZvVnl1c2VsdUlTVGgyUzJDeWFHcWdpSWlGSm9oWE12QW92?= =?utf-8?B?bkN6SjBhMzJMSGJ4aVQ1KzVwSGxsYVJRL2JQdnFYcHNkOGFDNlZzVkh5R2V4?= =?utf-8?B?MEh5Y0JSNGtwd2FHTmRZZTlQNjdwazJBOTc4RUtNc0hIK2ordjdLVlR6M2di?= =?utf-8?B?My9wTURUZ04rV0h5WXVJaUovaU90WUF5SWYxMmZudlFTdUJyTGdvREg0N0kv?= =?utf-8?B?dklRU0tNbno3THk5YUswSlJHcVpPQjNvU1ZGTUYrRjNDWXNDYkVjRUtCNC85?= =?utf-8?B?N3hSSDZGdFhaaVlRYXZKZEhSamZTM3FlSWZTM0FhVTR0RzZqOUozU0tvRkRr?= =?utf-8?B?bFhtUUMwSDh1d3QyUHlkMlA2eEhqN2tpSC94N0FlMnNjQWRwMmp3dElRbUk4?= =?utf-8?B?UFIzRUk2TUF5bHlQY3JHOG0yNnlSZlBIMnRCa1U5YWl1VURieTFRZ0pjVWly?= =?utf-8?B?S2djVXMwYXF4U0NsazBFYkNWSkFUR1dMMjc4MVFERHlqZmZ4UldPM2dxVndU?= =?utf-8?B?bG9hczZVaStlSGxZVkxSOXRWa1lXd2d2YllGcVhqTWdtTVRHWFpPZytSQ2JZ?= =?utf-8?B?WmJLMUYxaStSSjFlOWNVTjgrZzZ5ZmdMNXRwL0FEOElhc3FUR2c1dlpMNnlz?= =?utf-8?B?QlloZG16TUY0a0s1TW01V0JLY1JXNmt3cnljc1pERHZSRW42WFEra2N6bDVs?= =?utf-8?B?UHF3ZWxOejN1L1NhbkN4TmovK2FwU0Znb0tiZkZqSmU1WlV3NUV4L0JUL3ky?= =?utf-8?B?eGNMUnNvVENnaXQxcndaTThzcEhkSy9VU1U0UjV5a3RycHRqaHpmTEVjUkI0?= =?utf-8?B?U0JMQUZoNU5vL0VBOEY3TDd6d0VubVhoN0JmWHcydWZSRkJxWFY2K1JMOG9L?= =?utf-8?B?ck5vVElYK3hkaVArZHNJN09MZXBIbkZLQ2ozZzNHQ082MkNOY1NxbGhIRkRi?= =?utf-8?B?anF0VUpUUG5CWko4RytRMUlZbTVtc29MRFhVOGgrdzhXSERMaXcxdTd4amJG?= =?utf-8?B?R20zVFE1SE1XU1BRL3lTYkZybTRtUWNtSFlJY3loQ0FNUDRzT25wNDZ1V1Ns?= =?utf-8?B?OXprOWMrTi9sQzFkakUvVFNqcm5PRHo5WEhDb1dkcWdPWnlpMWdtNVlwS0x1?= =?utf-8?B?WDlzOU0vUjlGU2pHdzRpWjFjL0Eyb0dGd2ZJSFpHU2xTYnRNQ2xVejNKdDQ4?= =?utf-8?B?MEVGd00yUnR0SlJuODlaSXE4QlNNRDVpQkJNUUlmODNWRFZkVklJZlowUGxY?= =?utf-8?B?c2tYN2RFdUdsMU9yMitOdHlRL0lmaDd3a1BWV3BXTGY1dFNQQ2FITC9PTTlE?= =?utf-8?B?bFdVN0JxKzNROXlrSjllUFowRXU1emprNlRMREZkYnp3Yy8xSXIzM0xwWnda?= =?utf-8?B?YmlJOGlQQWlkNFpYRUhSM2dDZW9GM3Vpd3JON1Eyb1RLRk1kSWxnM1ByYlJI?= =?utf-8?B?SEQwQmgvbjRqeStNaFJLd0psR1VpaVZCSnJyYnhHNzZuUlBVUXpmOW44Q205?= =?utf-8?B?RU9RMCt0SVJnOHVvdEcyT2FQNHZ0WlRMVUd3VXRySGQ3Y25FSTE1azVLd05U?= =?utf-8?B?NWhpSGRLYkJhMzBHQlYxSFVYYmRvQWo4WitGVXdwM2x4WkdIblFDLzRpY1lF?= =?utf-8?B?d1V3UXZvS1FrdGlYVjM4VXBPek9JTFRzVVZYazNRTE9MWkdrQ3h3d3dWSGtl?= =?utf-8?B?K0U0UUtzSzFsbTBsTkhlWlpKWkJOci9XK0QwbDJEVkszSG15REFJbzBDOVF3?= =?utf-8?B?NzJiMnY0N09BTFE5b1ZMcFM5SW9qRFZ2bGNjakZDWkxacjJSOWFxRjVZakhj?= =?utf-8?B?RThqd0RpM0oyOGpYU2RndUF0aFlvdFZORS9BMnRuOGU3anl6eGhYdUZKUk45?= =?utf-8?B?S05xanZ4bHhobjliMm9QS1hYUVBiOTJIMTVPL2pCeXhzM29GRCs4b2lGbndV?= =?utf-8?B?Z3BkTWpRUDNvSlFyMmUvUDlTa3JFTDhSRk9jUUtrY3RMeGt6Q3ZKSTZ1Tlht?= =?utf-8?B?ZG8rOWNzbXVlNUlSYm9KTStLR0lHamdYVCtmV3I0c2tCVURpY2pnTUIvbVha?= =?utf-8?Q?kSRS5PuHmpN1or9k=3D?= X-Exchange-RoutingPolicyChecked: FWzDc3LIGJSCx6UdDGOxwo85bO89orLLT0Ye7oGxpvRH8HIg8M2qhhwZt5kFy3TNwF8lZqs6rL4GpFVQbYud6Ybr1IkM5vzV2BWuvEIFl1WZckxmcrHzYsjeKOvLqezMmdHFZRFWyDvlszHBnuAu6Q+eF6eNCJWxC3vryVnuYVf8ZlAqVAuxgrPiRq0evPaMY9K4copoE8aaDYUb8WoXM+mIRUhvRb5XQLEZmJoPd+punXwx7BNRQMoKbTP701H1BwLfS+Rxv1NjkZwBjz8q8u1Knw3NRot4t8zXXAjbvUuNCNBfPPPIetzX9NrAmvtgW7UF0AC0STbmWEV159jEQw== X-MS-Exchange-AntiSpam-ExternalHop-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-ExternalHop-MessageData-0: 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 X-OriginatorOrg: oracle.com X-MS-Exchange-CrossTenant-Network-Message-Id: 481f4185-3dab-4abc-4f53-08df36740e83 X-MS-Exchange-CrossTenant-AuthSource: CHAPR10MB997722.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 30 Oct 2026 10:53:40.3542 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 4e2c6054-71cb-48f1-bd6c-3a9705aca71b X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: OtVMedO8KxHP+ETdSHnywK5kh9Qx40gP1zlCL0p+iAEdZyngLh0VCyQWuY+nhWRpasEhwgmJ6LxxfOEA++7kTjH6WwDC9nlmNF4arpA7RsA= X-MS-Exchange-Transport-CrossTenantHeadersStamped: MW4PR10MB6464 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.138,FMLib:17.12.100.49 definitions=2026-10-30_03,2026-10-21_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 phishscore=0 spamscore=0 lowpriorityscore=0 mlxscore=0 suspectscore=0 mlxlogscore=999 bulkscore=0 adultscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.22.0-2610190000 definitions=main-2610300042 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYxMDMwMDA0MyBTYWx0ZWRfX9KeWMypexTWl BLtsoYTRLKPD7ow/3FcjBVjZITsYLSjAPGwSRhHDREel35ObkSYzX8eK2DN8b0y20c5Ebv4T7Ew 7Y0M/R9CBTyz5gvwViwknYpUBC+E8m4+b/qscGmDJu4q1c+Nw/Rtwq+9zlMLKWBK5WAEXtWewEZ Ub4zU001hNsodla+bjPwOqq4SFKPIMoz8/IjKxQ5BQfeqXlnFTKrQ/7IUu7hAMlWd2S97A63CMO pVHQrXpUR6MxBYai4SQLCnPrjjNBn3pDzEmslPA8CknJkEvUGL7ZINlTc1le3zirkeHVluw/ZEQ sXWmfmDTPB5idhy7l0y7fMnndalVzX7c59pcsfEpaffA7/IHj8gjkNQ3y5e21teuODkEQtOIFoY 9875orE1suPKdox0G/01j6cSW8872AAseCzejfySR/PlBb4Me8pc6/irp31eGV6rf+pnxa0ulYT 6jtv9sEwOZMf0pyJ9rQ== X-Authority-Analysis: v=2.4 cv=SI/Xx+vH c=1 sm=1 tr=0 ts=6ae47737 cx=c_pps a=OOZaFjgC48PWsiFpTAqLcw==:117 a=OOZaFjgC48PWsiFpTAqLcw==:17 a=6eWqkTHjU83fiwn7nKZWdM+Sl24=:19 a=z/mQ4Ysz8XfWz/Q5cLBRGdckG28=:19 a=lCpzRmAYbLLaTzLvsPZ7Mbvzbb8=:19 a=xqWC_Br6kY4A:10 a=IkcTkHD0fZMA:10 a=660iZSQnnn4A:10 a=GoEa3M9JfhUA:10 a=VkNPw1HP01LnGYTKEx00:22 a=jiCTI4zE5U7BLdzWsZGv:22 a=RD47p0oAkeU5bO7t-o6f:22 a=VwQbUJbxAAAA:8 a=pGLkceISAAAA:8 a=yPCof4ZbAAAA:8 a=968KyxNXAAAA:8 a=fybzUvBd16Gubq0c39sA:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 X-Proofpoint-GUID: kUwGkh62DTHmDxieY_dYcBwu4sTmy93t X-Proofpoint-Spam-Info: AW1haW4tMjYxMDMwMDA0MyBTYWx0ZWRfX3jDsExY0nJfN VJ6zcCqZHCi2UJGU/spKc7SVmr6Vi4fOYlNyGGWhqKuoTbZnyR2zaDO991TmECuhbJx2gr5qxKl NXseYtOcVCkIJX4rlBxrsQI4YryK7NZUtx6X5SU+WO2yKjbUosY4 X-Proofpoint-ORIG-GUID: kUwGkh62DTHmDxieY_dYcBwu4sTmy93t On 16/10/2026 15:06, Muchun Song wrote: >> On Oct 16, 2026, at 18: 00, Joao Martins > wrote: > > On 16/10/2026 06: 49, Muchun Song wrote: >> Static pmem Device DAX > namespaces reserve space for namespace metadata before >> the user-visible > >> On Oct 16, 2026, at 18:00, Joao Martins wrote: >> >> On 16/10/2026 06:49, Muchun Song wrote: >>> Static pmem Device DAX namespaces reserve space for namespace metadata before >>> the user-visible data range, and may also include padding needed to satisfy the >>> Device DAX alignment. __dax_pmem_probe() adjusts the dax_region range to start >>> at the >>> >>> Static pmem Device DAX namespaces reserve space for namespace metadata >>> before the user-visible data range, and may also include padding needed >>> to satisfy the Device DAX alignment. __dax_pmem_probe() adjusts the >>> dax_region range to start at the data range, but the dev_pagemap range >>> still starts at the beginning of the namespace. >>> >>> That is not valid for compound devmap mappings whose memmap is stored in >>> system RAM. Compound page initialization requires the start PFN to be >>> naturally aligned to the compound page size, because the head and tail >>> struct pages are initialized according to that geometry. If the pgmap >>> starts before the aligned data range, memmap_init_zone_device() can build >>> compound page metadata from an unaligned PFN. >>> >>> The resulting struct page layout is inconsistent with the Device DAX >>> mapping. A later mmap fault can then resolve the user-visible PFN through >>> invalid compound page metadata and hit a kernel panic while inserting the >>> DAX folio. >>> >>> Fix this by advancing the pgmap start to the aligned Device DAX data >>> range for non-altmap compound mappings. Leave base-page namespaces >>> unchanged, and leave the altmap path unchanged because >>> memmap_init_zone_device() already skips the altmap reservation itself. >>> >>> Fixes: 14606001efb4 ("device-dax: compound devmap support") >>> Cc: >>> Reported-by: Ritesh Harjani (IBM) >>> Closes: https://lore.kernel.org/r/wlrkqqvg.ritesh.list@gmail.com >>> Assisted-by: LLM >>> Signed-off-by: Muchun Song >>> ---> drivers/dax/pmem.c | 7 +++++++ >>> 1 file changed, 7 insertions(+) >>> >>> diff --git a/drivers/dax/pmem.c b/drivers/dax/pmem.c >>> index bee93066a849..d3a9b85107b0 100644 >>> --- a/drivers/dax/pmem.c >>> +++ b/drivers/dax/pmem.c >>> @@ -51,6 +51,13 @@ static struct dev_dax *__dax_pmem_probe(struct device *dev) >>> /* adjust the dax_region range to the start of data */ >>> range = pgmap.range; >>> range.start += offset; >>> + /* >>> + * When the memmap is stored in RAM, exclude metadata and alignment >>> + * padding from compound page initialization. Otherwise, the pgmap >>> + * may start before the naturally aligned Device DAX data range. >>> + */ >>> + if (!pgmap_altmap(&pgmap) && le32_to_cpu(pfn_sb->align) > PAGE_SIZE) >>> + pgmap.range.start = range.start; >> >> Should we need to check here for pgmap.type == MEMORY_DEVICE_GENERIC ? >> >> Considering the dedup is not quite applicable for FSDAX. > > Good point that FS-DAX does not use compound devmap initialization. > However, pgmap.type is not set until the Device DAX or FS-DAX driver > probes, so checking it here would always be false. > Right, I forgot about that part. > The pgmap is also copied into the static dev_dax and reused across > driver rebinds. Moving this adjustment into dev_dax_probe() would make > its range depend on the previous driver binding unless it were > restored on unbind. The removed prefix is only metadata and alignment > padding and is not exposed to devdax-backed FS-DAX, while its > vmemmap_shift remains zero. Therefore, keeping the adjustment here is > harmless for FS-DAX and keeps the static pgmap range consistent. > > If you have a more elegant solution in mind, I'd be glad to hear it. I don't. Thanks for addressing this: Reviewed-by: Joao Martins