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 56A39C61DC4 for ; Thu, 27 Aug 2026 15:51:55 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 5F3366B0088; Thu, 27 Aug 2026 11:51:54 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 5A4246B008A; Thu, 27 Aug 2026 11:51:54 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 492D16B008C; Thu, 27 Aug 2026 11:51:54 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 226416B0088 for ; Thu, 27 Aug 2026 11:51:54 -0400 (EDT) Received: from smtpin05.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay08.hostedemail.com (Postfix) with ESMTP id AEF52140481 for ; Thu, 27 Aug 2026 15:51:53 +0000 (UTC) X-FDA: 85147490106.05.52E946B Received: from SJ2PR03CU001.outbound.protection.outlook.com (mail-westusazon11012037.outbound.protection.outlook.com [52.101.43.37]) by imf14.hostedemail.com (Postfix) with ESMTP id B71C1100007 for ; Thu, 27 Aug 2026 15:51:50 +0000 (UTC) Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b="K5vpZmT/"; dmarc=pass (policy=reject) header.from=nvidia.com; spf=pass (imf14.hostedemail.com: domain of ziy@nvidia.com designates 52.101.43.37 as permitted sender) smtp.mailfrom=ziy@nvidia.com; arc=pass ("microsoft.com:s=arcselector10001:i=1") ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1787845911; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=IqM/D11UhKb56tMg8U/tR/GyGoVA3HWgIT4/kY9fQM0=; b=eJzp5FqldmLV7VAclWoTBB6EoD46F4dQM5zqiSx7Y/Vmj9Yjx0LPARgRZO2WWVJ9/+dZ4H iVXtRrsqGq50+0wsVvcUryLTPeoXCPb9DaZm1JfI3bG0VWcdwDiTmSD5Ng0a0Odc0cJFrq K35nrAfsz/Ht2koO6otaUK5jcjJpKV0= ARC-Authentication-Results: i=2; imf14.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b="K5vpZmT/"; dmarc=pass (policy=reject) header.from=nvidia.com; spf=pass (imf14.hostedemail.com: domain of ziy@nvidia.com designates 52.101.43.37 as permitted sender) smtp.mailfrom=ziy@nvidia.com; arc=pass ("microsoft.com:s=arcselector10001:i=1") ARC-Seal: i=2; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=pass; t=1787845911; b=jECgIN0z/pbChd70X4U+x00VFxI0u6G/uQNZBxRtZtQJpfUYW0Zw/s4GM+SA/7JfuIzfx1 geWSOFJk3PVg+7Ga6X49JsBUg6qZqT/GcWlPeGNoQLNC8oWxEpDl+Xwz6F3AF3ADAJkxOi BTvRdQAbkuc11kApwRsvziRI9tOMdf4= ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=bx/XqXh90P6Y02G8BeCrtNciQMS20xhj82XVxxPD0LF7hWM4LAB7hV2RMDopC9iLuZphkmNjoUynah+apGYG/cfvwmjyiAWuvPc+Qx3hj8JHWfEdn6QtT+IiPpnJWx0GBfwFnoS52BlCOh2zIj5Aqqcx576wkf6oZAj0udcmmIdf2Oteh+WY7dMRYqLV0KLV6jcNYsUIr2f8Y/9KIPbpFxPxNN4NBn16BA7Y9HPvZpNvVEIEtTfozLaeXcatFN5AVE3QUhf8deHxJgGi3ATrpZaNQ4zf18u1EZxz29pKHCJBDY13xcA20Lc/4sGJPor2NJmbQPkrEkAw+PFBRy+jRg== 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=IqM/D11UhKb56tMg8U/tR/GyGoVA3HWgIT4/kY9fQM0=; b=XFhcjTUjYtFRvOXOHmu3iIo/QfnDybQE0+Sm691YF99Jx0BYq0jNZnV3fes87Phzd2uWpGORPdDLoLnhHe7LnlbADlFZ312scw7Dfj46xCFgkS4w83GuQfsI/Q/2gv7CEfmH7TRw4t5gFL8xushXTeK4qjG+iKAiPEk4ASLxkkdR0esWqSfmtyfOG69z1gaHY8QYFksvcpixP/8FESDenyASs7pVbMWq+uyGMOh9dkSk103FJDsGvAidtiluponKpT/sM0RgfEpI8R3Oa17cSGQ/LqfqaoqcDlyipFZnMK56y0oHu7HaeT1IvwHNGjHgmpK1GLyCsaDmd9TswwPdSg== 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=IqM/D11UhKb56tMg8U/tR/GyGoVA3HWgIT4/kY9fQM0=; b=K5vpZmT/vOGCuvahSUCjLNQC+YPrtFJEu57xC86MFqXPEWSqncGivzUFKxdie8lPwFs2Ax/IskCGwIcvECBZE2hDxZAFKumUvwx9FCpyUxYc+BPS17vvMJ/I+7ZES9OdOu0qImH4bsdEGKj020joI/Dx6DKTMV0GOUfScinX41iTqXANLP/HKoxFrTM0ql1fcFRUYDzJMY0hZNmKHP7ygopCjAmsBLG3k2JxMH6Z5qplovoKPe3XnNpbUaqZ3NmL0wriE+64+TfzkJrjSj+AAY7k9i/qfoXEMi4R4VoM/JrGiLTgqtXUfc4y3niSxpsXuCo71FQagQV95Vela/MuFg== Received: from IA0PR12MB8374.namprd12.prod.outlook.com (2603:10b6:208:40e::7) by LV9PR12MB9806.namprd12.prod.outlook.com (2603:10b6:408:2ea::7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.360.10; Thu, 27 Aug 2026 15:51:45 +0000 Received: from IA0PR12MB8374.namprd12.prod.outlook.com ([fe80::d85f:4c87:ae84:3f16]) by IA0PR12MB8374.namprd12.prod.outlook.com ([fe80::d85f:4c87:ae84:3f16%5]) with mapi id 15.21.0360.008; Thu, 27 Aug 2026 15:51:45 +0000 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Thu, 27 Aug 2026 11:51:44 -0400 Message-Id: Cc: "Andrew Morton" , "Hao Li" , "Christoph Lameter" , "David Rientjes" , "Roman Gushchin" , "Alan Stern" , "Greg Kroah-Hartman" , , , , , To: "Vlastimil Babka (SUSE)" , "Harry Yoo" From: "Zi Yan" Subject: Re: [PATCH] mm/slab: reject unsupported kmalloc sizes X-Mailer: aerc 0.22.0 References: <20260817-limit_kmalloc_size-v1-1-5bef487701cc@nvidia.com> <82f138f5-11d4-4839-94a3-c226fd982715@kernel.org> In-Reply-To: X-ClientProxiedBy: YQBPR0101CA0306.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:c01:6d::28) To IA0PR12MB8374.namprd12.prod.outlook.com (2603:10b6:208:40e::7) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: IA0PR12MB8374:EE_|LV9PR12MB9806:EE_ X-MS-Office365-Filtering-Correlation-Id: 17ecca88-b8d1-4ebb-8be0-08df045318cc X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|23010399003|366016|376014|7416014|6133799003|10067099003|11063799006|4143699003|56012099006|18002099003|22082099003; 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:IA0PR12MB8374.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(1800799024)(23010399003)(366016)(376014)(7416014)(6133799003)(10067099003)(11063799006)(4143699003)(56012099006)(18002099003)(22082099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?SzVZaWptMnpjUWxhVWFldnh6NGNOMEFVRFd5bDVYdU5KZ1NjeHgvZjVzTC9t?= =?utf-8?B?aG93ck8rbzdpMXVQQVQ2UnJtWlpVd0ZkRCsrTUY0M09lS2d3eGkrbG5aZm5a?= =?utf-8?B?alVxZzNRRU9Xa1ZNRG9wZWJrTFowb09Pc2U2V3pnenNwSEF6c2FjWnlkVWVt?= =?utf-8?B?dm53blE3Tnlsc1FjbzdsaTVHRTAwN1dBWGM5MHZWeWNCdldrdGp2UmlzOUJS?= =?utf-8?B?di9aNHRIcnluVUo2bTdQZHQ0QUw1ZU1oaW1lM08wM0lPaWVaVlcvb2dYRmxx?= =?utf-8?B?cGNRZVZhN3BGYzNxaU9zN3ZWeXgzaytEMFJSa2JlaE9OOFY4cCsrMmw5QlZY?= =?utf-8?B?MG9pd0pKdG9sZzdBWSsybnhBMGlGV05EOWJDMXdzQUErVHBtL0lYeW5pMXlS?= =?utf-8?B?NjlvZUlCTjZrMDdEc1FCYzZ6dTZPdFdXN1YzVW92TG13MUg0RjdBNFZacnNu?= =?utf-8?B?YjlSMjNyZnJTbnIrL0FVQjFUamlNbW1kcy9SNm1WaVRDV0VqRHJKeTBVemhx?= =?utf-8?B?THd6YUZvdVNWT0FMTHRiZk9iZ2haOUlXRGtpZHgxL2pGbkF1VUVCQ2toSXNS?= =?utf-8?B?WGFkblhQMWpGQXdRdVIrczB4cXYrbHBCdkxPVVo3SllLSzQ4aU4vbnlVWjFr?= =?utf-8?B?UCtWdkd3cjZUa3MyU0ovUEQ3Wlk4em9XMTE2eUFnOGlkWU5LS2R4VTdrcHlJ?= =?utf-8?B?b1pPN24xSzhOMHBVWlRONEljZzU4RzRqQTgwMEtnZ0txQlAyc3ppTFpIU3di?= =?utf-8?B?aHdJVDZOMUxHaUhnMGdoclBEZGszZ2hhMXRvRVNJa0VWdlNMZ25IUzZndHV0?= =?utf-8?B?OEJuZGRmWjVVcGpHeFZpeXJDbmh3Zk16R3NxK05PendQVlFIYTRUNkl4YTNm?= =?utf-8?B?SWNtWXI0NlhkZFk3bEQ4R0FlUnNwMUpwVXMxTUdaeWhEVlFYVEswaTlBMHU3?= =?utf-8?B?bkIzRzBVclFlQnpJR1B6NmZvTFM0TXdEVjUxZk5naGhEcTQwYk40RWQvNjVH?= =?utf-8?B?UEtrRlk1MWxIZGg3TkxHQS9FVkhKakZnamhJTUM1OHV3OW9IQ1NoVUVad0ov?= =?utf-8?B?cUFYMHQ4U1laSGJEQzRqRDZqVDR5Z2FGWTNHcHRLSmdjWVA3U1ZvdVZaa2N4?= =?utf-8?B?VVNLN1l3OUtXMERQTWYwcHE4V2lBeThsWXVKalV4S1diMDF2VFB3bFczVEs3?= =?utf-8?B?Q1ZabUYrYnZ3Y3E0eDgybUx5V0pjQ25keDg4ZHhUTGVRYUFjQ3VKdlZ0ZVRT?= =?utf-8?B?TEc2SWlyWEZYVlZ0ZlFNN25oVFRqVWszVzUzTDFXZXpjaVhzdTE1R2ltUlpn?= =?utf-8?B?WStYdjVMc2NvbjZpakMwWmJUYjk5SVl5Q2xEeXdXYUdCdVN3ait3WUR6MW00?= =?utf-8?B?MUJaTU5ybU5SaTRVMkF2YXF5ejZtMWdqL1pTM0xhcG1YZ0ZMQzNkYWpmaVFB?= =?utf-8?B?dkhlaW56YlVOQ3BiRXdiOWdKemYwcmFCWUtIaHlveUY4ZG1nMVdCN1RvbjBM?= =?utf-8?B?WkY5MWtoWUI3MkdMSUkwNkw5VHFPNmZrRFNHcEJ4b0lwRFpFbWV4a2RtbjIw?= =?utf-8?B?eUs1d1RMUmJSK1VtamJSMEt6Qll0YTRWK2NqTG9OUllnSDAvMmx1OEdUUmlR?= =?utf-8?B?QVRBc3dhR3dNL0xnZG9tMXNoZDliMGsyZ2JyVm5yMCtaMWttTHdDdzZpU1NL?= =?utf-8?B?N1JkOGpEdVpqRVZKejhMcFZiMGlLMFZQN1g0aEdXQTc4NUMrYTBEemFWMXZZ?= =?utf-8?B?SUp1bWx6SDNZajBQWnpZcnQwUDBUSm9pMUlRNlpNb0l1K045RXQ3aVhyVnJw?= =?utf-8?B?M0p6WFRTajVyb1pYRVJXZW9DQ0NaazVrRTQyREM2RHZtd3RmbTE4WWRSVXQ0?= =?utf-8?B?Nml1L3ZBTHh2L2FHcXVtRkhFNjI3QzQyRGpDNkJjM1ZOQnA2ODdURnEzTXNw?= =?utf-8?B?TFZUS3o2SVAyK0hlRXhNbEF4dGZlQTdkQVo2ZUZMYmp6eUJjSUd0bmxiMkY5?= =?utf-8?B?SDJwTnlLQkF6OW5ZaWtLOW5CSUhJWGRKL3N4TDVmdmd4YWUwQ0hnMHVxZTkx?= =?utf-8?B?eDNqTGU3NnZlRXUwZ0sxbmVxRG96U3JaNlM1emZkTWYxUGEycTRiRVE5STlL?= =?utf-8?B?c09Va3RBN2hOOHRudDRMRWViemZjRTQ1cXZDMUNZTEpaeEZ6NG1rUzZHZC9Y?= =?utf-8?B?VkdlQkF4SFRPU05vUFBOL3RjVW55bWtYSXN3bzYrK2hhRjFxeW1ITW9seFZU?= =?utf-8?B?dkZKcldKTDhvd3lVRVdZM09CUXpYY1QzZ2pTQXAydllyNGxkUE1JUktwdHhk?= =?utf-8?Q?WRokZY+y6GDukBWO7K?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 17ecca88-b8d1-4ebb-8be0-08df045318cc X-MS-Exchange-CrossTenant-AuthSource: IA0PR12MB8374.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 27 Aug 2026 15:51:45.5726 (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: kKnrEsQUXWMtJuN+0UjVblrb8m1dH48Fv1qNRM1CLEq5hnmoNNaUjrPO9kAcd282 X-MS-Exchange-Transport-CrossTenantHeadersStamped: LV9PR12MB9806 X-Rspamd-Server: rspam11 X-Rspam-User: X-Stat-Signature: 91uehdqihp3e56isdxgy9dikneiw9dof X-Rspamd-Queue-Id: B71C1100007 X-HE-Tag: 1787845910-11421 X-HE-Meta: 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 tCZwOHY+ 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu Aug 27, 2026 at 3:47 AM EDT, Vlastimil Babka (SUSE) wrote: > On 8/26/26 11:52 PM, Zi Yan wrote: >> On Wed Aug 26, 2026 at 5:47 PM EDT, Harry Yoo wrote: >>> On Wed, Aug 26, 2026 at 11:28:12AM +0000, Vlastimil Babka (SUSE) wrote: >>>> On 8/17/26 22:40, Zi Yan wrote: >>>>> kmalloc is used to allocate physically contiguous memory for kernel >>>>> allocations. For requests larger than KMALLOC_MAX_CACHE_SIZE, kmalloc= uses >>>>> the page allocator and can only support up to KMALLOC_MAX_SIZE. For r= equest >>>>> sizes bigger than KMALLOC_MAX_SIZE, the page allocator can emit a WAR= N >>>>> because kmalloc allocates an order greater than MAX_PAGE_ORDER. Syste= ms >>>>> with panic_on_warn=3D1 crash because of this WARN. Fix it by rejectin= g any >>>>> kmalloc size bigger than KMALLOC_MAX_SIZE. >>>>> >>>>> Fixes: aadb4bc4a1f9 ("SLUB: direct pass through of page size or highe= r kmalloc requests") >>>>> Reported-by: syzbot+805630f1453e490427fa@syzkaller.appspotmail.com >>>>> Closes: https://lore.kernel.org/all/6a820ebc.9ebadd4d.20b15e.001b.GAE= @google.com/ >>>>> Tested-by: syzbot+805630f1453e490427fa@syzkaller.appspotmail.com >>>>> Signed-off-by: Zi Yan >>>>> Cc: stable@vger.kernel.org >>>>> --- >>>>> It fixes a page allocator warning (order > MAX_PAGE_ORDER) when gadge= tfs >>>>> requests excessively large memory from kmalloc. Instead of adding >>>>> __GFP_NOWARN to suppress the warning, as was done for usbfs[1], chang= e >>>>> kmalloc to return NULL without a warning for this specific issue. >>>>> >>>>> [1] commit 4f2629ea67e72 ("USB: usbfs: Don't WARN about excessively l= arge memory allocations") >>>> >>>> So I checked and for kvmalloc() we have in __kvmalloc_node_noprof() >>>> >>>> /* Don't even allow crazy sizes */ >>>> if (unlikely(size > INT_MAX)) { >>>> WARN_ON_ONCE(!(flags & __GFP_NOWARN)); >>>> return NULL; >>>> } >>>> >>>> This comes from Linus in commit 7661809d493b4. I'd do the same thing h= ere >>>> then. >>> >>> But the purpose of this patch is to avoid the warning in the page >>> allocator. Should we fix this in the caller (gadgetfs) then?=20 >>=20 >> It is fixed by: https://lore.kernel.org/all/20260820223719.A4A3C1F000E9@= smtp.kernel.org/ >>=20 >> Please disregard this patch, but we can keep the discussion going. > > I still think this patch has some value if done as proposed above. Yes > in practice it will just replace the page allocator's warning with a > different warning, but IMHO it's "nicer" if kmalloc() sanitizes its own And SLAB maintainers will be Cc'd. :) > requests to the page allocator, using the KMALLOC_MAX_SIZE value. Like this? Or the exact pattern as kvmalloc() is preferred? diff --git a/mm/slub.c b/mm/slub.c index 0337e60db5ace..b562f2a6fbbee 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -5263,7 +5263,12 @@ static void *___kmalloc_large_node(size_t size, gfp_= t flags, int node) { struct page *page; void *ptr =3D NULL; - unsigned int order =3D get_order(size); + unsigned int order; + + if (WARN_ON_ONCE_GFP(size > KMALLOC_MAX_SIZE, flags)) + return NULL; + + order =3D get_order(size); =20 if (unlikely(flags & GFP_SLAB_BUG_MASK)) flags =3D kmalloc_fix_flags(flags); --=20 Best Regards, Yan, Zi