From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from CY3PR05CU001.outbound.protection.outlook.com (mail-westcentralusazon11013040.outbound.protection.outlook.com [40.93.201.40]) (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 EDCF72BE7DC; Mon, 13 Oct 2025 17:11:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.93.201.40 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760375502; cv=fail; b=JQ9LHe0azI6F/0T+RFrYjj63X45YnKAKqIwkQ2NmrETgf6MK3TfzRX0HnUxUbc7veZvmUnURbD2iNzC9kmdTEKEREdEPQTzXInR5eNmS3z2S6M09gNbej9GPR600Mr1qsNN8EA4o9XRGY2zhzpCi9s/hDKXyIWJ1OsAJf4XlHQQ= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760375502; c=relaxed/simple; bh=6SjKgO7O8DRgaJxrYqgMIrWX9rneYZ9bA0ElKlgMRqE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: Content-Type:MIME-Version; b=T3/FALSbU8btsWM9YPAWS8UXGTjJ6/AOk97cxjrdtN8pkTM7vB+J++eCzlwzrK5vsY5STm8jGCMoHKXiBfx41Y5j3Wu1kBwzQAmtZBx8EwJjtZAKlyMaxwdNvYDfA8pPH95IY5+2lA3YcMCg0+TPwtjswIQ97rK2MaCVD3/kd4s= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com; spf=fail smtp.mailfrom=nvidia.com; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b=jJO+XDjY; arc=fail smtp.client-ip=40.93.201.40 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=nvidia.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b="jJO+XDjY" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=gTCBGjnDLQ1yEIRqGZTbCgphvdSL6iOJIuRnh+SNdNeeV2fJRvjaXzvDtynC5qQJCB4YKaZB+VohamAvvbMHwCCqZJbk63xWqvoAmAEIPeHcpHb/cnA4o0JR64aYyil9BCJZ9ISuH0p2cq93GprTJiXbuYtt4JshphhgWwirNDvITw7SCyx2Wow4S2hImhdol1VEL6+BkVtiuUxrtLlLLAAHmYF2AsDIYdEm4V9Mgcu46NlB1rFeqaP8wGTeMMINR/3vMi0XtBA2Ykn9vXZrUUwMe/XuURILEpJsKrz8qSg05ekLNXZDMQ+XTDUKHA3EsDXY60ayGzm60RjexpLFBg== 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=6SjKgO7O8DRgaJxrYqgMIrWX9rneYZ9bA0ElKlgMRqE=; b=CsL8DhgIVQ0ND5LRkWq5UuSEQclyfN6dCoBE5Q9iuXfhEQYeaEoF0vcEjJhQ1vVkN7PNSTgsuanXfdtVdyoCnCXo5qQwCI3s4BOA3rdEdjghLGGxNxSM+jmxBJGh/SsDrqsAsdo+gM8f014BeUU1lGIVY3tWLTN29oOoz51fL3s2SLihyBF5FFUAgHjz2oQKAj8MKqS3cntcq/vibmBCwgcJCjVarXybfaG+t3X6GOuZJZEl9PGaNlCFYWQeUbixfYvpUZ6rur7HNJX1PFwMpPLqVcDLP/myW64/W85rmKqk3/dL2GKjCk6xHfmeDh1Bo/XT0bboY7Ul/u9iU2O6Cw== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=6SjKgO7O8DRgaJxrYqgMIrWX9rneYZ9bA0ElKlgMRqE=; b=jJO+XDjYbDVl7ASAFBx635LXgbATrekbkAkDSBrpHxTv/7s9ZtknEUE2Q51iiQjJIn1ZhDrrF62ANIUEsi5/QZcRvjzNNCLmfeOrnkc/GbPKWdzawLUgoZ+9upyE3TmwfEtXBgm4M4XphT1qnhdOnq50bbzcuBneL6nfl8nynHBLgDfXQygYE3/vv53VHJrJeUnP3rqeMPDWIerEzleHeCGCH1/+EVrhSYcsj2ecSnYlnsK24QY96HRdmtZivpEMJpc3zxkXs5TtDsVnZ1DVb0BFsn8oXjJyY19GxJig1XnnNXkALyMOdLwAqzrESnB6C98QtVyh52CTa5q7KG+nng== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from DS7PR12MB9473.namprd12.prod.outlook.com (2603:10b6:8:252::5) by DS0PR12MB9728.namprd12.prod.outlook.com (2603:10b6:8:226::9) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9203.12; Mon, 13 Oct 2025 17:11:37 +0000 Received: from DS7PR12MB9473.namprd12.prod.outlook.com ([fe80::5189:ecec:d84a:133a]) by DS7PR12MB9473.namprd12.prod.outlook.com ([fe80::5189:ecec:d84a:133a%5]) with mapi id 15.20.9203.009; Mon, 13 Oct 2025 17:11:37 +0000 From: Zi Yan To: "Pankaj Raghav (Samsung)" Cc: linmiaohe@huawei.com, david@redhat.com, jane.chu@oracle.com, syzbot+e6367ea2fdab6ed46056@syzkaller.appspotmail.com, syzkaller-bugs@googlegroups.com, akpm@linux-foundation.org, mcgrof@kernel.org, nao.horiguchi@gmail.com, Lorenzo Stoakes , Baolin Wang , "Liam R. Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , "Matthew Wilcox (Oracle)" , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 1/2] mm/huge_memory: do not change split_huge_page*() target order silently. Date: Mon, 13 Oct 2025 13:11:35 -0400 X-Mailer: MailMate (2.0r6272) Message-ID: In-Reply-To: References: <20251010173906.3128789-1-ziy@nvidia.com> <20251010173906.3128789-2-ziy@nvidia.com> Content-Type: text/plain Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: MN2PR03CA0028.namprd03.prod.outlook.com (2603:10b6:208:23a::33) To DS7PR12MB9473.namprd12.prod.outlook.com (2603:10b6:8:252::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: DS7PR12MB9473:EE_|DS0PR12MB9728:EE_ X-MS-Office365-Filtering-Correlation-Id: 30cfe654-0e32-4487-4dcd-08de0a7b917c X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|7416014|1800799024|366016; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?IkWq2Mrsy3fDUEhcI5MwOKYHpVHPJC9t1hb6S1saBYLK+XaK1GpXWAvnVxEP?= =?us-ascii?Q?LE1ZxzhzSsLnanzCodagnmwTtvGaYj18LtlVJ+zq+aC/Xs6MzeC/Uap3ez9O?= =?us-ascii?Q?JTMP9UNMKM5rjwr2dX8h83ec8PKDzPJZc5Jg5O9uDxulEBJp6ThvAH0r2zb+?= =?us-ascii?Q?QaFF7p0SY+HnUrsuJpAMMTWxtSqnjZbTlk1gS4oMrkvfKyZcojf1aVwZHUTl?= =?us-ascii?Q?dB379klu4tQAj+q3/ulDoG7TUYmrEiB7HQsXrYiEfgxpG3bkk8pM+x7/CTL+?= =?us-ascii?Q?rqW5c4pWLMBnFrASOYEdGNOsDCZW6PZ1SZ6DOF6rBpAPi7rvkvpA/LQW2e2q?= =?us-ascii?Q?k1dUZr3Kv4fJtzyeoGpnjEG37GjPVXQ694Ii/xFhR2eMVSq03YP4/PMB8lk5?= =?us-ascii?Q?/PowiOK2gdX8nUKZzdjJGtdxq//+ilAMpxsQDlqpNayMQcmtByVoVWF7/qvg?= =?us-ascii?Q?rT9wGLukPE9qHrBrJGSBKkVUfbFCf7eR4n9zHz2Bim4bRyBC7MMnV2aWEsim?= =?us-ascii?Q?ufrIeoy+53kd00ZGsSXs0Cu0K93gOHXpedGyfhjlBcqGdtwoIAq6V286QHS6?= =?us-ascii?Q?k60djHjmqfVThyXOwupzM84r2P3N2eWXCFjrGfQ9eUhkKIkJDFcQgMC+FciO?= =?us-ascii?Q?eeWq853k/qZsVx6Cx9hjjZ4MyT3WI3nL45YDwtCVpkOMsKlIDRiou3zSF1/K?= =?us-ascii?Q?TrlPXqRSrzSGFHhvnzU/jijUuHkmsxTaIkdw87lwwQYNy1slJr0EUm8UMc5J?= =?us-ascii?Q?cW7scmXSjoC3F2WwsI39DPQlJlwxjQ55vsfJg4AGyERHDfiOAzYLkIPj8h+d?= =?us-ascii?Q?PVLjgtMFhHKFkqXU42XHiAqHKemfpI2nle9zEc9PnaRWmfo9tYNkw9RwDHmv?= =?us-ascii?Q?RBlPNB3NaLh235Qp6/vkj8fV330uOk1g54gGrhDBt2ifJu08NGd6Q4nM66x3?= =?us-ascii?Q?HUvj646CpTaYwl0GkG0n7XqYr9Y3dWbKvObRrwVv5k4PdCkBgarXc2Ofz3f3?= =?us-ascii?Q?FB0kLq4y/zF8DnpXftl4csA9urdJJMzoJBw7yi03HhbpE80QuzMAjXZR+a7D?= =?us-ascii?Q?DfyK+vCmCWlWJTkDevZFKMEwDQjWNVHP03djV5n48Iq4O0b9obt+mVKSaXMU?= =?us-ascii?Q?BL21Zpb+d8FD2nvm1mTCzEevwuh9Oay9ADlVIxj2PeTigTqsoTkf6KRV9VkB?= =?us-ascii?Q?LhUlqdP/C9iZFMG5bfQzkymxUDSkvfLDivcZRa8ie9HPnldmS9sPcKL/zsR1?= =?us-ascii?Q?4xNlhG6EofxY+SqPhUNpnZ2NttJAYJskSU+9XYA+RCkWgA8gKOBXQVy+4XVN?= =?us-ascii?Q?cMmUURmY5PG6LAtnVvI/bMumZsLqcRpjhJeuNQIlpGP29lhdL9UTcVltlt7S?= =?us-ascii?Q?DBb8Rq1hvA43iX4+TyzKETZFb3xk3Dn+3odY5+z/CQB4tNxpVHBc5FxFuiGt?= =?us-ascii?Q?/+iruqrsMzCBbXfAUzco08hznhxSRMiCEYrt7Aveb2M3MbUV187tOQ=3D=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:DS7PR12MB9473.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(376014)(7416014)(1800799024)(366016);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?ANBbBko1SdqKxR/tJ1sBKZvj13X7Arx50TMvnvyWNynDps4JoKRLYSlJA8e7?= =?us-ascii?Q?5E8A/A3WoxQfq1mE12CeH/D6tFNmjs2WvjBM0XPJmUTOUJuqTROB5sMku5eu?= =?us-ascii?Q?WFMtPt4uf1d3jKY7kXtOT0BjTEGSMlm8+X2z14q+W/Dc+jhTRse3/BDTIOws?= =?us-ascii?Q?FTZus9Ti0pUXOIiLpWvE4gaPvB5EWec9GPv+YiSL/gK1PzzeA8y5t5X1b34i?= =?us-ascii?Q?fHp/7AXz39FBxF60FPk58o0tEosZYY5ejSAUIowjk8vfgDnbpvWZ7EygsUHR?= =?us-ascii?Q?rAtrDeo0/0wh/tNZDXpB6WkEKBPXqhuXScrxbNkvplDMl2c46i42Et4MP+MF?= =?us-ascii?Q?5YKKwK5bvjP98qVjxeRHR67SMD41TR6VVapcgCWvBULbTdl6yMC0+OP8m4dA?= =?us-ascii?Q?5AYo4suv5Gp4GOsgDtbRk2jcv26IGciUGZSt4xjIJmtrnCgWXAEw9U1WKRMs?= =?us-ascii?Q?sgdQQ9T/qWYrdoRgFBMzq2rqXb+6E7iDz6nc8nydWS6Nqh7MlRO0PkAAedpt?= =?us-ascii?Q?rGzwlrbPeB6z3iA1S7j3vJh5om1Tat39JvYqOxQEqjIcUTb6J6DfLQPyCg/2?= =?us-ascii?Q?hr5V2DUYu3TNJlqbqTMCRO/qmgff6BWibmSjzL2bbrmyGG6f0WVQLRehRxwp?= =?us-ascii?Q?Nf9h2Fa5a8UEAH+O/bswNqQd/6PUNi9CQGsEG7yFWsGuQSmMPWz0+b8Iluqq?= =?us-ascii?Q?KSJkptdtBCb8wbIQ8eTIYOr2gB1x4z/tvJlgU8Xmm7/S+fSk2zD2LtSBWp6l?= =?us-ascii?Q?o6R1FwTbJ5fCTVIQhKbkf/Zuvtcbs8bE4KBNQ3njC/0vOsS64CIWdiRKzwE8?= =?us-ascii?Q?M7UkeQT5YPtZBjh4cli2CuOcQZoklZjioZX2NZHaxs8vldfGg4XrJcAAZ3j9?= =?us-ascii?Q?VOxLUlvlMQBWn0lrDXdPdNuS9Fd3Ccs0zkVK8dHW6ffoy9zLx7ItHVKzr3S+?= =?us-ascii?Q?Dmw4KKWdT772rtorV2CTK1ZPmbQw909+n1HlS3yHTq9w1LTP5QcG4jEdwSby?= =?us-ascii?Q?zKKUr7RWeyQHDaR1BZMp6q6dZoAqN8RShitnCbZ/+SH7BRkG84QUCduXRtqt?= =?us-ascii?Q?vEfamAaaUaOIq0k/GlRiE+AWo412iHlqtgDMZkw5JtZ61hj3VSxDd6Rv+SN/?= =?us-ascii?Q?KX/+pVlbDQHYZdGvU7n9bWZVyDF8zqmPeRXceWbsrhQ/e6GUdFZnMbps4oLg?= =?us-ascii?Q?3w2r3aNpXjgfg07GNclhNE5kcvPQt7E5no44AWNc9gxWBrfBq93/MusXRTYG?= =?us-ascii?Q?fII5GvYdlqG1SwvFdaxlyw1qt/CaaQT6ewBBROWRE4Fxkt4G3kKrdmqsHmu3?= =?us-ascii?Q?FU8KM7W8Hf0VUGtqFbrw6LXEhGjU0Myl1Fq5iF/x0uqJjAp986vK4haqhxla?= =?us-ascii?Q?RFGrKkx2QjF70ZKHmPoFlV1RLn7SNOAzdNIwsTG6hz0KxoCGzQrPtO4KNg/T?= =?us-ascii?Q?cwB0nBT4UkiSkuRxVeXz8MdmkdgjNSXcppKGtgQJi/muvbdKXY/1JeJkwW+a?= =?us-ascii?Q?JybylydP31cVymkM+l01YKNOC1K6Ky9zhJoDCcpo480/vGhPeQ+MLjI1WgEH?= =?us-ascii?Q?6QPmlR+g6keZdY7jSNr/0bkBSTB7ihLhwVCKAfG9?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 30cfe654-0e32-4487-4dcd-08de0a7b917c X-MS-Exchange-CrossTenant-AuthSource: DS7PR12MB9473.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 13 Oct 2025 17:11:37.2644 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: 5BZwRA1bGz0X3J2Qn43ADOliQw/cgWFH7sGTMXDV/hn5gE6ObZ6pT4X7DL/b3LU6 X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS0PR12MB9728 On 12 Oct 2025, at 4:24, Pankaj Raghav (Samsung) wrote: > On Fri, Oct 10, 2025 at 01:39:05PM -0400, Zi Yan wrote: >> Page cache folios from a file system that support large block size (LB= S) >> can have minimal folio order greater than 0, thus a high order folio m= ight >> not be able to be split down to order-0. Commit e220917fa507 ("mm: spl= it a >> folio in minimum folio order chunks") bumps the target order of >> split_huge_page*() to the minimum allowed order when splitting a LBS f= olio. >> This causes confusion for some split_huge_page*() callers like memory >> failure handling code, since they expect after-split folios all have >> order-0 when split succeeds but in really get min_order_for_split() or= der >> folios. >> >> Fix it by failing a split if the folio cannot be split to the target o= rder. >> >> Fixes: e220917fa507 ("mm: split a folio in minimum folio order chunks"= ) >> [The test poisons LBS folios, which cannot be split to order-0 folios,= and >> also tries to poison all memory. The non split LBS folios take more me= mory >> than the test anticipated, leading to OOM. The patch fixed the kernel >> warning and the test needs some change to avoid OOM.] >> Reported-by: syzbot+e6367ea2fdab6ed46056@syzkaller.appspotmail.com >> Closes: https://lore.kernel.org/all/68d2c943.a70a0220.1b52b.02b3.GAE@g= oogle.com/ >> Signed-off-by: Zi Yan >> --- > LGTM with the suggested changes to the !CONFIG_THP try_folio_split(). > > Reviewed-by: Pankaj Raghav Thanks. -- Best Regards, Yan, Zi