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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 95AC1E63C8D for ; Mon, 26 Jan 2026 13:01:13 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 072606B0089; Mon, 26 Jan 2026 08:01:13 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 0208C6B008A; Mon, 26 Jan 2026 08:01:12 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E10136B008C; Mon, 26 Jan 2026 08:01:12 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id CD3746B0089 for ; Mon, 26 Jan 2026 08:01:12 -0500 (EST) Received: from smtpin03.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 87D17D39FB for ; Mon, 26 Jan 2026 13:01:12 +0000 (UTC) X-FDA: 84374125584.03.9B63468 Received: from mx0b-00069f02.pphosted.com (mx0b-00069f02.pphosted.com [205.220.177.32]) by imf20.hostedemail.com (Postfix) with ESMTP id D77511C0005 for ; Mon, 26 Jan 2026 13:01:08 +0000 (UTC) Authentication-Results: imf20.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2025-04-25 header.b=alObnc8M; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=VxQVIGRK; spf=pass (imf20.hostedemail.com: domain of harry.yoo@oracle.com designates 205.220.177.32 as permitted sender) smtp.mailfrom=harry.yoo@oracle.com; arc=pass ("microsoft.com:s=arcselector10001:i=1"); dmarc=pass (policy=reject) header.from=oracle.com ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1769432469; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=MS8RxKeRWhV69Yj/VtUfJxRcOQWHBde2MHDFsukZe6E=; b=Z7nO0erP3/NKrcakYzRmZDhYtkVwI5DrzFcuCpuIgnas36ZYut6EOcflst+xJ94Y0cejWB cLQGM+4wxiDSRmXarb6dq893coX8B65fm586uAtB0DbV84EyYfKOPx944tf32asrwilW5/ lp3lk2+MFC+6JSa2wuE2ty+2e6uerMs= ARC-Authentication-Results: i=2; imf20.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2025-04-25 header.b=alObnc8M; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=VxQVIGRK; spf=pass (imf20.hostedemail.com: domain of harry.yoo@oracle.com designates 205.220.177.32 as permitted sender) smtp.mailfrom=harry.yoo@oracle.com; arc=pass ("microsoft.com:s=arcselector10001:i=1"); dmarc=pass (policy=reject) header.from=oracle.com ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1769432469; a=rsa-sha256; cv=pass; b=5LVFy47I8NyNmvsSE6fytL0bZ4vqjnQN+yo6+2t4cGwFuPJIGJIi5hhJVTP5DphiYPRHf4 Z99EhrZdbPaNFiGE4F+/gfAMBWmRXt6V+DyotXgb+pq57lvMbrNqQ0ilr/g56CNBEUUcH7 +gnUSpk0Run8eRoM/mE41DDkdv0iL4E= Received: from pps.filterd (m0246632.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 60Q3CtVs871441; Mon, 26 Jan 2026 13:01:04 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=cc :content-type:date:from:in-reply-to:message-id:mime-version :references:subject:to; s=corp-2025-04-25; bh=MS8RxKeRWhV69Yj/Vt UfJxRcOQWHBde2MHDFsukZe6E=; b=alObnc8Mc5AHpfnnUhmNatmEiGQC2rK7MG FfI0/PkXg63l/3/7iprfuFL0GqStfyFB/cZHh3aJX+lTdIoSQE5j9GOCBptOMKAA Ffgr1zYbLmXGAxrhU7Ouy8Gg+ZdnlYLP3UrLi3I2do1gej8KExOL5/FCP9Uiwt8C Bu/oGa3MNqbBvXKsRn9UKyVGBZNzXz6Wd+bcWW33pgCTXNaJxLcUmyXgcZGzT/og R5mzwx1rxwJ1/Z4Xuh5cnqyVoflwreVzJKP+6rtIb8xz2dT4IP5730XRCnrAGNT8 FUzMCBA2CaVJLQgDWgWX8zcXCRIraaaofqFrGCB8Fbhi8P1XNoRA== Received: from iadpaimrmta03.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta03.appoci.oracle.com [130.35.103.27]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 4bvnps9s5y-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 26 Jan 2026 13:01:04 +0000 (GMT) Received: from pps.filterd (iadpaimrmta03.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by iadpaimrmta03.imrmtpd1.prodappiadaev1.oraclevcn.com (8.18.1.2/8.18.1.2) with ESMTP id 60QCEc1a036089; Mon, 26 Jan 2026 13:01:03 GMT Received: from mw6pr02cu001.outbound.protection.outlook.com (mail-westus2azon11012022.outbound.protection.outlook.com [52.101.48.22]) by iadpaimrmta03.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTPS id 4bvmhm62ny-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 26 Jan 2026 13:01:03 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=xJTYeh0Bpe81No5H8+Dr9yinFvsEBFiKnSe5V/OsdPZzQOlsRNTlbeTvhuZz0zR5ghIxYIh2rMhd8I8m+SO7jlZOvx4m2acuiRfraGzrb9GK9a45fw4cGRCbiqzeuT0vWxkeY5oGaJ/jVBFYnUEqGTRlpx1I8/PsHduRAr+idSDLUZkDEXnJvK/Lol4/gRBBif6RwvoYPhWxlVlRLrbAz7nnldrnSvlX7YIk9wiJDYmD0LoabktzUQgjMKggkyZ7TMmIbIeNdJTUfxIxDkq8EV9EvAuAj04nVNzaswFgaifV11HsMqC+qAmbj8FkApL0r/yFlm/bBsdXXuvXd2Wo4Q== 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=MS8RxKeRWhV69Yj/VtUfJxRcOQWHBde2MHDFsukZe6E=; b=R+ibPnZTxMflJUdAlVvsG1ndWHm0irizbloECzZ/pBgAPRxe61oRCA28mlJ9yxG3QMPXgqwWNkIfP+eA71eoAfx0y0KHxOsKoUDwgMFZRXbRaGxMt0v/457iZ8bdRggLd2+a0yu379yHAimP2kFv9Er2pBRmmzCZyg/C1tfiSjeYEP1TqdLAPFn54TrARExYYHm1ZsdFkTR5yYc7zknmVA2qahVQODsMgmk4KPkLry8/xX5kEVxVXGApRkOUB/v0hFxnBAYxCeTgRYKFVjml8dYlnbGYCeyMkZlhkO+X2+WI1SMLvkLFS7/hrJPNhNKg1oQaYgvWmOAHfilhk1uvqA== 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=MS8RxKeRWhV69Yj/VtUfJxRcOQWHBde2MHDFsukZe6E=; b=VxQVIGRKgRUIC31JUUumbIOFulr0PhoqycMYCjk+FLr0ZgNW7Hw/s4upcedXRmc1zcSTFkld0fwmVS2D2Zb5Qm0d7l5ChIwTVR3HYzDDzbPp/Utat49FGzgPJTBBsLFRHSR5umEk20yFrHWfhULbuTNKWv3QTEnBaMWovzKnyr0= Received: from CH3PR10MB7329.namprd10.prod.outlook.com (2603:10b6:610:12c::16) by SJ2PR10MB6963.namprd10.prod.outlook.com (2603:10b6:a03:4cb::7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9542.16; Mon, 26 Jan 2026 13:00:58 +0000 Received: from CH3PR10MB7329.namprd10.prod.outlook.com ([fe80::c2a4:fdda:f0c2:6f71]) by CH3PR10MB7329.namprd10.prod.outlook.com ([fe80::c2a4:fdda:f0c2:6f71%7]) with mapi id 15.20.9542.010; Mon, 26 Jan 2026 13:00:55 +0000 Date: Mon, 26 Jan 2026 22:00:53 +0900 From: Harry Yoo To: Hao Li Cc: akpm@linux-foundation.org, vbabka@suse.cz, linux-mm@kvack.org, cl@gentwo.org, rientjes@google.com, surenb@google.com, kernel test robot , stable@vger.kernel.org Subject: Re: [PATCH] mm/slab: avoid allocating slabobj_ext array from its own slab Message-ID: References: <20260124104614.9739-1-harry.yoo@oracle.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: SE2P216CA0032.KORP216.PROD.OUTLOOK.COM (2603:1096:101:116::9) To CH3PR10MB7329.namprd10.prod.outlook.com (2603:10b6:610:12c::16) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CH3PR10MB7329:EE_|SJ2PR10MB6963:EE_ X-MS-Office365-Filtering-Correlation-Id: 6b7c156d-f37c-4915-50e2-08de5cdaf0e7 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|1800799024|366016|7053199007; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?8k+8VHdE73jZHarRqnTL65bVDfiaSFL/11WhsqACUsl3rCsN+HD2EFQT5bvD?= =?us-ascii?Q?but3lgmMWCQvk4NGYAaYgId4mI+kzkt7yz/0MrWnvm8b0v78tBco35yrfurr?= =?us-ascii?Q?bjvvexwoDxyH68CgCDdFtBXnuZq0AASjJ+hao6Akol2z3e6NOJEkdS1RpVco?= =?us-ascii?Q?PahgOP4RqHblrSuI3/7vf6PsUPYMPpglXj5+3LHNDmY36r3z6+PNfNnCbqiJ?= =?us-ascii?Q?qd0zjiD6TxGRGhYnDH745coif5CTuobmSDsHacLAaM3HxUhrq7I4RTxPa4h8?= =?us-ascii?Q?+pNdT60S/dvk+5gE7yaoJ0QwmbgqQ+bPB54jk+dv7bULRQJzVgEadGjYkW0E?= =?us-ascii?Q?YTAChXKAYbbYxvxUWvoyL+YV3y8o5ov2+6NQCLMLCLnA3yoA6Zoh/O6hLv99?= =?us-ascii?Q?LPlVyNbVmk9s+2bboFAzEKs0HgNWkKBOHE6gb8Z1yxcNHYYQqy1GNAUpIXcm?= =?us-ascii?Q?CM0kvmoyZwdZj+TcCKWHTlrt+qbGPRxNmQ6hKpOkHex+McmP96Q+i7b87Ysq?= =?us-ascii?Q?XfyJP4nE/PlRv5XMpqDKboRTFV6SKJx4s6kxEEH76lp5qwE/4WCgbWyjar91?= =?us-ascii?Q?UuGt5KNv5xevih1n4jw92kI9tzV5EluK/exuQyyKNjwBvjCwI88kvdrOrgu/?= =?us-ascii?Q?7aFy2SakcoK8gsaf7sBDi5TotGH4oNAx4fR2GLMGY2UazFL89+GoATjbhjyj?= =?us-ascii?Q?E0JKGgaVOZobQrMI84l+p9TX9+pKGwvuMt7ds7Djd13fBVlCIAVHxmnlvmdg?= =?us-ascii?Q?zEtMjxdQuWQ+fu4oH+3QxT+GUwlMP4cjiwPiaBavqPVg6+eDbGE0sikjKLs7?= =?us-ascii?Q?PUhPoNuPIJdVZI7o5d+9ZGbumc7eYe8/TY50C0Q+V2ejnEZMCbg+S0Z7Bpnc?= =?us-ascii?Q?iyeBPeKDTIo5KrIWmfWCNvrbcdAt6V0SIzTgbu3l7YoyOHslpdQU9xsVCOKd?= =?us-ascii?Q?OkumG0i9NUAPBGojRCd6Zvks2O/K1CHhtPwmp3InqKv/3dEAxeEW3J+LjbKz?= =?us-ascii?Q?6/yVJ1bg4utttTaHbncguwlxi9QRDcg7gwW7gledgxZLkbZ8NwJoIWM7NPrM?= =?us-ascii?Q?eu82v6xyjqk4Mu8SqNVNXWyVEEJZFJTaRhRU5bObPqH3Oadvv9Qe1yglaeSY?= =?us-ascii?Q?y2hcuuPrkOIH5+r6XmrGJyGZRZGHtNZyQ1VNJY0I9si2NihILhadCukU6vsX?= =?us-ascii?Q?nbWxGrn6xoju+lzWKf1Sb3GupxC8UO1rVmr7JBRSsWAQi5DVDyttxgGZ7tUD?= =?us-ascii?Q?rnlQV9KtvYf8pJyuXOJV1yuQnYwmzF/Ry+yMCqKRSwgfE3BtiQLG5xDCqCpE?= =?us-ascii?Q?5zv4x9/tUAZUukTv16QNZY0wW+/Mcj+IvG3CWHe3Xw/WhhsV9OLHaYS9GXLn?= =?us-ascii?Q?kbouyxe2ZP+J2W5+ew3qzSdtyhRJZBA8yINDjALRRQ5+7LWQApanqzpfe6JQ?= =?us-ascii?Q?X/fpVmm2jrrsp4OVwqG4aZ2B8DgGvZZKesorzljmnWuevt4zqAc7qAJsxvfm?= =?us-ascii?Q?BIZ+RHETKfgOZJKYqDWstqQkFQUo17VKq0P/LJGuQROSqjsEwCxqDS2myMfp?= =?us-ascii?Q?IWnDkLHj9zJmZt2t5aqvyVXx5+r4gNv+qmigzX82?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:CH3PR10MB7329.namprd10.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(376014)(1800799024)(366016)(7053199007);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?0G4ubQ59xP1jF8/0DPJHsgoX1spxcfBWhu1zq9ds6ljqdNubVSlEVmA5mZmg?= =?us-ascii?Q?Aoouioe07m9oUdumoxGOPQM/4A6O5UCerN/d+wpT9jBLmxq/vl/JBh5C5Kk8?= =?us-ascii?Q?3HjJQNyPyRI5BIwXEGsCZXZrEABLlC3XYSk5ddxTDAL4JQCVGW5zhesEqMZF?= =?us-ascii?Q?kIkwlDxutqZ8qIp43ToP4jVOs07pStxtIFyLlZ9l8SacI21tfUBSLuwhv19l?= =?us-ascii?Q?HkKB9o0ltLeWWAjBgyI90GGsaFDjxDSWtKPMUK0ZxJH2TGVk4Sj6bc+OND+c?= =?us-ascii?Q?LBlVcE4Rb17cuLn7kZHDLjGZz4CgnslnvAup0a0f0gG6w5qp9+LigkPqyr8B?= =?us-ascii?Q?+EiW439f2yy7jCLC32N6wGDFbYRVi3V6j4V1Wn1o8mE2xbwWivsT1anODGV8?= =?us-ascii?Q?JmH5e3aHrAg8NcGz5WKrRPrhfV7MYGKtJENRL8bayNXtGmFcSfc40W2d98l/?= =?us-ascii?Q?e0aEZ5qzP9VsW3yyVF6bPaDfYa7h0hPX4qkltbx/LHTDscWNKcG74fedX44i?= =?us-ascii?Q?LfOt1uiYU2oS9iQCoEnUjzhPyhARUyDx4arU5dIBSaJEPcrIQqvGwy4Wrj3e?= =?us-ascii?Q?3vDwAlwRSTc4kjrlmuX8UxcFNCN95CgbtVLObRW7ZOZ2q/jTJSTPmKON/U9z?= =?us-ascii?Q?NB48l8Gt+bMB7f6ZD+WUvw5m+iBLEhxeZqoP4TnBhZD7zCthpH4X75HDurpo?= =?us-ascii?Q?+Wf39W2godlmBtwdxbgG0q/HHuydA8NgIYAgZNSO6977wSm+pR47Pzc+WUPz?= =?us-ascii?Q?H/AO9l2y86385GTyNNtgSODgKtEfhuVcXsFmX19naKKja7eWWHjaRckS9MfK?= =?us-ascii?Q?2q2J6QCh3lPwyAaDYTF/NvI5YJDgmGC4ugsAB3edKf5HEqLfOd7H5wwrzWeW?= =?us-ascii?Q?EfoxqeCsczgdHRW+E+EOZfQFaMAPZP4HStgq0LoL5gNj5gcZLpwJGOL0YB3t?= =?us-ascii?Q?TPyWMB7NtIaiwwb9GOUu9No55lEe4fKJAePn8miy6HpowyzO8yyCaRUs+T/7?= =?us-ascii?Q?n6M+QuOC8yO8OtL9cIVBXf+PbGbIu5VTvY4gSECRhoOE26JJCt5SPV7UILuE?= =?us-ascii?Q?7vZ/3bgbGguMEB4qqW+TXqOE1F1N5l6xe3FH0JEgbtD/CoP5qlkwl+ArN+o0?= =?us-ascii?Q?v/jPt8SdJT0bQnKmJt81eSN+Z6jDtc7rnQ0CyOa/zgPpP3R1xHE6ySYDp0Dc?= =?us-ascii?Q?rBYYwtpqe2d3i3gWG+CwvsA4BZjMP7Kj9z8C8ha+dxg2t4nomzzztq0FcKXD?= =?us-ascii?Q?K+cN34uvvxpXxEiVvRluMYcsYvqK7CQm96SqAjbkRagEYCsETCMfc0iKypYW?= =?us-ascii?Q?9RWMrt4aq1BQmLLLBHu5BYGP09DqiJnSW9totT8tcgK+Y4O5/EQVp3PjKMZo?= =?us-ascii?Q?S3gALE2Yvo9JHKcljFCAt81W/Sjlxe+jhQiiKcsvZR0AA/kU87OGOhvjTQIx?= =?us-ascii?Q?jJ35ks1LXcFYqn1FWGXUnYpvPGv9XCchYQj8b+yb9fTBLM/88fypYiTks3SM?= =?us-ascii?Q?QqojH4w6zim/KRyenXP27V0JeyKxLRRNnleNtQdOxN3eKnDKOr/ZPRnkKYJX?= =?us-ascii?Q?1paAWrxrv/8KOJq/HfPuAStOJfe2Fm+cn3bPGLs7GV7iQA5mNOmGe74LdCt1?= =?us-ascii?Q?J5XVytFd6Kl4AGO3A7KUv9s5m0jKNOZn6LDHOmraF1JUowWfgCxJk4gCwFGP?= =?us-ascii?Q?HYNEygj7cFQZ/v5EDzuVunB3ixtKWVdWAx1huaOJCmpnG7M4zBJy8lpYn9dL?= =?us-ascii?Q?3aGLgP1l4Q=3D=3D?= 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: 6b7c156d-f37c-4915-50e2-08de5cdaf0e7 X-MS-Exchange-CrossTenant-AuthSource: CH3PR10MB7329.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 26 Jan 2026 13:00:55.0740 (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: 7ZHuKWpTE1pfi23A/qT8EaqMKFRJMCTXg6sXKo2S9kJ/JccbYca9gtMGHIcPQEZSiYWT0vYxO5wScEe5Jek3mA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ2PR10MB6963 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.20,FMLib:17.12.100.49 definitions=2026-01-26_03,2026-01-22_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 adultscore=0 bulkscore=0 mlxscore=0 mlxlogscore=999 phishscore=0 malwarescore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2601150000 definitions=main-2601260111 X-Authority-Analysis: v=2.4 cv=dY2NHHXe c=1 sm=1 tr=0 ts=69776590 b=1 cx=c_pps a=qoll8+KPOyaMroiJ2sR5sw==:117 a=qoll8+KPOyaMroiJ2sR5sw==:17 a=6eWqkTHjU83fiwn7nKZWdM+Sl24=:19 a=z/mQ4Ysz8XfWz/Q5cLBRGdckG28=:19 a=lCpzRmAYbLLaTzLvsPZ7Mbvzbb8=:19 a=xqWC_Br6kY4A:10 a=kj9zAlcOel0A:10 a=vUbySO9Y5rIA:10 a=GoEa3M9JfhUA:10 a=VkNPw1HP01LnGYTKEx00:22 a=VwQbUJbxAAAA:8 a=QyXUC8HyAAAA:8 a=yPCof4ZbAAAA:8 a=3gxr2GW5v6rFuv8lLXwA:9 a=CjuIK1q_8ugA:10 cc=ntf awl=host:12104 X-Proofpoint-GUID: pXt80Uy2bMOLoMRusRA2IsF7sdCtsIjP X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMTI2MDExMSBTYWx0ZWRfX9rPemdAc+tlW bqweq97Mx18bk3rrlfGUJcOCXofzLRPu+Ct2gQ/rDsyvl/GTVZsU6AKnKhHhgXsvjxHQVMDSZaj yClS22tiv+wCqPjir3dK02mxi4VuntdYFzqcd7DUJ2KB2Cxwfs7j8yGUBBwXX5uknNR8e0Boy3l ESGCOcEURxD3O7oGX5Ysg+rjoJjNH0gyVup7/UOrQY3+683Qk8qbg8GdCG4IZix5TCkRaYpsr3V 0G5KlTYwxqhX5T8S5u2Xs87KnepViOLDrHABVXuOt4+FM8WBJv9edVLa0OPOR9DpxyqOnu08i0C x4QcVjMGyR/buzKufZqnIlW/6tp75QSUbf7wepl5gokldNQAQdfgpE23TKLgL9TFQAg8D2Zrb7l fR2JpGVy2hs8wF6VwkVJu6jKAsgaNx0y7FSMlJx2Sl9uo92qhGQqYiFs0QI3a01hHAhEhBj6b3e JLVo/51TKt/qnzznz4QAakxOyKQj123UrkBmeksU= X-Proofpoint-ORIG-GUID: pXt80Uy2bMOLoMRusRA2IsF7sdCtsIjP X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: D77511C0005 X-Stat-Signature: ozx6ue61ixobrgu5weh1xi9wd55q8tzs X-Rspam-User: X-HE-Tag: 1769432468-571987 X-HE-Meta: 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 yj7YfPz2 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Jan 26, 2026 at 08:51:10AM +0800, Hao Li wrote: > On Sat, Jan 24, 2026 at 07:46:14PM +0900, Harry Yoo wrote: > > When allocating slabobj_ext array in alloc_slab_obj_exts(), the array > > can be allocated from the same slab we're allocating the array for. > > This led to obj_exts_in_slab() incorrectly returning true [1], > > although the array is not allocated from wasted space of the slab. > > This is indeed a tricky issue to uncover. > > > > > Vlastimil Babka observed that this problem should be fixed even when > > ignoring its incompatibility with obj_exts_in_slab(), because it creates > > slabs that are never freed as there is always at least one allocated > > object. > > > > To avoid this, use the next kmalloc size or large kmalloc when > > kmalloc_slab() returns the same cache we're allocating the array for. > > Nice approach. > > > > > In case of random kmalloc caches, there are multiple kmalloc caches for > > the same size and the cache is selected based on the caller address. > > Because it is fragile to ensure the same caller address is passed to > > kmalloc_slab(), kmalloc_noprof(), and kmalloc_node_noprof(), fall back > > to (s->object_size + 1) when the sizes are equal. > > Good catch on this corner case! > > > > > Note that this doesn't happen when memory allocation profiling is > > disabled, as when the allocation of the array is triggered by memory > > cgroup (KMALLOC_CGROUP), the array is allocated from KMALLOC_NORMAL. > > > > Reported-by: kernel test robot > > Closes: https://lore.kernel.org/oe-lkp/202601231457.f7b31e09-lkp@intel.com > > Cc: stable@vger.kernel.org > > Fixes: 4b8736964640 ("mm/slab: add allocation accounting into slab allocation and free paths") > > Signed-off-by: Harry Yoo > > Looks good to me! > Reviewed-by: Hao Li Hi Hao, thanks a lot for reviewing! I was tempted to add your R-b tag, but since the implementation has changed a bit, could you please provide R-b again if V2 [1] still looks good to you? [1] https://lore.kernel.org/linux-mm/20260126125714.88008-1-harry.yoo@oracle.com -- Cheers, Harry / Hyeonggon