From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from SN4PR0501CU005.outbound.protection.outlook.com (mail-southcentralusazon11011064.outbound.protection.outlook.com [40.93.194.64]) (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 2E4122D7D3A for ; Mon, 26 Jan 2026 20:43:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.93.194.64 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769460230; cv=fail; b=KzX88AEqvvv9Jofn1qpWKWbZBgZmMccmBaZX+ElCgf54y0xeoBZzMOf1/c/h2h78UWkwkWYrWYq0Zs+Q8drDMULCWhsX4R/reSoqoET4Hmsf3lubdnOBSvlV+PbEYy94/9S4fLkEGP0/Qg1/HSM7JyylGVG0cUZzr7ke0qZtGf0= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769460230; c=relaxed/simple; bh=heFnggNnz/MS0Ysg9VhC1VqzPPxfvmNcD4VGJ1aO52s=; h=Message-ID:Date:Cc:Subject:To:References:From:In-Reply-To: Content-Type:MIME-Version; b=Lamij8FuTT/A5Mf/Rgb93McRKewUpru7FjbN+k3qNxZKkugLHwUODMeepgKJev0Q0WNAG+k5tBN8E5Wnnj95lqRUjqeDygqk3eIuVTEFNdl6X8HgBbrlZ0Lh+y5qX4rrPPcrVl4pwzz3LtxzTnkcfn2L3Ruiqu16AAin/OGqJKY= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=citrix.com; spf=pass smtp.mailfrom=citrix.com; dkim=pass (1024-bit key) header.d=citrix.com header.i=@citrix.com header.b=LgbkJRRy; arc=fail smtp.client-ip=40.93.194.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=citrix.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=citrix.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=citrix.com header.i=@citrix.com header.b="LgbkJRRy" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=ivhHD9hv9V1k7n/+6xgO+RDOH+uNGln4pPIZJnqCbm1KQY8Kb7I1//xB9f56CUZp/zFShpG20cAPAcE/sp9DHac/uHyBuRIxGIBxft9pRffMuC2kNXb3ifqK4iodEMH4TLN7Vk1NrtuubGxCJ1+GAu3l9FepHdBXYVhbvuapRVam7VY8NYhRUEivFRQsXtHeYyTaiQK0KOCObiznhftY0rCjH8IG1WmBv0L2gKj0tTmPNsUxgzSQp4JLLlPQUKBFgKpttHjR+4HHKMuEic492Ay/WhHrqlNoJ0mNUkLSlVjAqgVSw1kns6u++wcZH1ClLxcOGoLlpg9HG8yCA1mcmg== 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=8NiIDGFxtwexQudYoSrpm/+QX0oGpl3fxTiLgEP6IhE=; b=E6xZSMh9GfSUmZzBfs+OYz/ssE23iuHleGixYrGmJWG13cj5YC5pHnsl0QY9RnSabnIJQOeY4JLxsFgvIg8Rn1+F9VbTH+mrZ/oxfYafQxuTR/PkJ5EgWnHy+4y+fgH2DKd5e4+GaVGZmnggLG4bi41kQeeqmqBq7GO2w9UiXeT/mHSdS354v8RwAXLWiRyfNq3k6oPbZm3UzXMpziO8gKnYueCF79pAxXm/T9pCKVtQMnFOAyX5l3CSKqVh3W4H8OJpO5unAKw8EvxCYMYwyknd6q1Lz3+mCcvUaTy46PEy+oc1KTSIE5AqxJs+5+At+IglFly1cmiYIyYUTSgxKw== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=citrix.com; dmarc=pass action=none header.from=citrix.com; dkim=pass header.d=citrix.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=citrix.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=8NiIDGFxtwexQudYoSrpm/+QX0oGpl3fxTiLgEP6IhE=; b=LgbkJRRyzGZt5nL1Zw7aVN0Gw88L1BpLh9ZYPCHsT5ghLVUlf5gJb8iUHCeMz96HLhkkJMMRDuQSlCgDCc2G9t5aI/j2tvORifCBwiQEt8lWWnXjOXgz+4J+SYfobzSCYoOQJtKpWys/vkPaWD5NT4qSYrwiDxXu6c3NyKxoTmY= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=citrix.com; Received: from CH8PR03MB8275.namprd03.prod.outlook.com (2603:10b6:610:2b9::7) by DS0PR03MB8296.namprd03.prod.outlook.com (2603:10b6:8:292::19) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9542.10; Mon, 26 Jan 2026 20:43:47 +0000 Received: from CH8PR03MB8275.namprd03.prod.outlook.com ([fe80::a70d:dc32:bba8:ce37]) by CH8PR03MB8275.namprd03.prod.outlook.com ([fe80::a70d:dc32:bba8:ce37%4]) with mapi id 15.20.9542.015; Mon, 26 Jan 2026 20:43:47 +0000 Message-ID: Date: Mon, 26 Jan 2026 20:43:42 +0000 User-Agent: Mozilla Thunderbird Cc: Andrew Cooper , Borislav Petkov , Andrew Morton , Marco Elver , LKML , Alexander Potapenko , Dmitry Vyukov , Thomas Gleixner , Ingo Molnar , Dave Hansen , X86 ML , "H. Peter Anvin" , Jann Horn , kasan-dev@googlegroups.com Subject: Re: [REGRESSION] x86_32 boot hang in 6.19-rc7 caused by b505f1944535 ("x86/kfence: avoid writing L1TF-vulnerable PTEs") To: Ryusuke Konishi References: <20260106180426.710013-1-andrew.cooper3@citrix.com> <20260107151700.c7b9051929548391e92cfb3e@linux-foundation.org> <20260126195431.GDaXfGd9cSwoH2O52r@fat_crate.local> <6adad05f-bd56-4f32-a2d5-611656863acb@citrix.com> Content-Language: en-GB From: Andrew Cooper In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-ClientProxiedBy: LO4P123CA0365.GBRP123.PROD.OUTLOOK.COM (2603:10a6:600:18e::10) To CH8PR03MB8275.namprd03.prod.outlook.com (2603:10b6:610:2b9::7) 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: CH8PR03MB8275:EE_|DS0PR03MB8296:EE_ X-MS-Office365-Filtering-Correlation-Id: b9d28a8f-7224-4980-8e2f-08de5d1b9a7a X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|7416014|1800799024|376014|366016; X-Microsoft-Antispam-Message-Info: =?utf-8?B?SzlPbnV2YkpTcVdpNS96aU1DVTh2ZlhRdlpueE12amRsRG9rTFZmdzVvSWI4?= =?utf-8?B?WWhoeVJYL3BwOWFkbWJOMHBPelhTUlJuTHBiZE1BNDNoQXRjaG9FMkFTWkVI?= =?utf-8?B?RnRWNTVja0kyUWhJV1dnS3h2K2NrN0V3ZXB1OGhHRktIOENDUzhUVG5ZZ0h2?= =?utf-8?B?cWJwV1lxV3NhOHNuUHVqQkdVeXYzQVRVcS9POEJIS2kvL1hPeFlnTmRFNmNk?= =?utf-8?B?d29KOUpPenRobENHRERvWVZSd2FuTFdkam1Mak1tbGhNdUFZRkJ3QVNoNFNl?= =?utf-8?B?eGlmM2JINzM5MlJOTmZ2N0NlZVNWdXcrbWRJVFlnZWlLUFFkMm01c0pPRWNx?= =?utf-8?B?SnNiYW4zVzJpRmtkUXlrVHBSa3h2YW9HSHBoMXhRN0U3MEVrQ0dDczRvQnBV?= =?utf-8?B?a1p6Z3RudEllcGY1N2d0UlNVMnNrdEY0VkoxencvKzY2Q0hYRUwwVC9yS3NG?= =?utf-8?B?aWV0VDJ5bDVBN3YzYVRDeDlteFVjVnNRb3NqWVdJVWttcWNUZHllVHJPNUwz?= =?utf-8?B?Tzg5VVhid3ZpbXZGelVYYjNjOFFEc29LZytwMFZNa29IeVJXN2tVak45bmRy?= =?utf-8?B?czFQc1RQRjRDdzR5QjNrUEFFbWVpL2g2cVZTeFJlRmZGZTEvWDdmYUtqRWxx?= =?utf-8?B?M0xDak1obnMxOG9GUm9VUWNoeW95OXJZVGxKUmdDUloxaDl1TlZwZzB2bS9B?= =?utf-8?B?TDdvSjZQRkJCOXFMNlkvak9zTy9oNm1oZlJMS01Edk9pWXIxYmxzRHJFREM3?= =?utf-8?B?Wkh3cmhZbm1FWmZ1TnEzeUpkdDBhVTRTc29KbWRRaDdUNzh1MVZBTHJGaDNL?= =?utf-8?B?MjJlSUppb29rYnNjTjJVdXZPemxsNzJ6Q3JGNmdETVpKZmFiWGlYaFBiSnp2?= =?utf-8?B?UGl4d3JsZVhuZVEyTUxZcE9GbVo0K2tvTlJGS1BIZnBiOHY1YXNqNzdGNWVi?= =?utf-8?B?NUhLbzhXNFZyRkhDM3ZETGI0M1c0RVp5WHNhR24zZm53TzdqWVl1c1JJYlVI?= =?utf-8?B?Q0ZYVFNPZisrSUQ0TUw3TDBxZXVwZVg0aXdBM3A0NUdCYUh1cWl3NXgxVWRY?= =?utf-8?B?ZStEVWpmMVFsaVlUSUk5Tm4zY2NNaEU3VC82bGt3L0RpUy9ZOGpuMnVLam9Q?= =?utf-8?B?MW56Y1VXU2pWM3NiWWJHRU1YbUJoWGFrVENFbEdFYTFHQlZ2L2g1Qm40Zkw5?= =?utf-8?B?OUFRcWQvZjRKbE85eCtSVUp2US9aak5CNUFWVUVuTEdIbS9mSGI4R3ZyR1Jk?= =?utf-8?B?R3NERnp6djd4d294R0xrWFVOd3JrZDluVmhGalJXMHlFUEFZTzJDNk12VzZp?= =?utf-8?B?eW9EaU96cDMxV1FIb2xZZzlpRi9xbzNkZ2ZPZDQwMjU2dEVoc1d1Z00zZ1gw?= =?utf-8?B?bkxjeCtXby82cG9Db1VtMW5ZaDBXYnNEdGlicHFqWEVzQzJVTVJYdHRDNGRh?= =?utf-8?B?KzVUNy9KVmowZjExMDV1K1FsbFlpNDQxNFh0dng0aDRoSy9kOXg2aEo4K0Ev?= =?utf-8?B?RHJGSEg1cGFSUklmajI4U2dzWVBnOHM3N3l6djlIWjg5RURVeTRrd2pzeXor?= =?utf-8?B?enVmMmExcUpNY2VQZCtPeGx2Wkh2NmxkVSt4eDYzK0xOdzJLYTd4alVlaHJm?= =?utf-8?B?WmZXaUJMbjlzM3BMbE5HNFN1SmJMbGpRbkxKcTNwWFlWLzVYckV1Nkp4dEU0?= =?utf-8?B?NENtYlcxSUZPdEI4VmI0ZEJWUEVXYVcvdUZSRVQzREpNSmgrNFNSOVFMdTBF?= =?utf-8?B?SlZjcTlpcTZyL3ZTQUFaL0hnTXh5R3BpN09LYnRGNmFjVkpVbDVYaTNVRWcz?= =?utf-8?B?WnMvYUdDMmZ3Z3FuaUdaQTRYVkdJb0VQSHRiTlR4Z0Zaa2JjTGNBYzAyVGMr?= =?utf-8?B?UitHT1lrZ28vV2NVNFJIbmZzakxlbWRuOEx2b3dheVRkZVJFY3ZNbHJDNzdM?= =?utf-8?B?SnVuZDlzQTg5Y09ZSU1DRC9xRnhwYmRMWmdZYUVMSDRlUWlkMjhoaEpEeU9v?= =?utf-8?B?SUQ1T1BDZlV4enRSbEdTUGJlc3MyeU9hcjRkRXVzaVBUVmhQZGtqaER0WDdk?= =?utf-8?B?T0NHdVhITFlOTFd1UHZzblFrTlJFKzFoWEk3aE1GVHBLaEpvNUxzdU12cFll?= =?utf-8?Q?dvXs=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:CH8PR03MB8275.namprd03.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(7416014)(1800799024)(376014)(366016);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?UGtjL2gvMkhMVmtNV2E0OVdWMWhtdGpSSmI2Y0xOVHhvUmVjS1NzNks3RExk?= =?utf-8?B?cXRQNEl5RklVTFJvdnpCWHVKU2JkM1BPalQ0N0pUTG5OTkxNRGRkVnZUcnFC?= =?utf-8?B?ZmpSQmJ5d0pZNis4eXVnclZFNVhxUjM4RkNnKzJSSjBzUDcxcVQxUC8razJC?= =?utf-8?B?eVhzN2ZPRU9zNTNuL3pqeFRpZ1habFdlSFNZdEhpOVFRTUxHaHpGM1FiRG54?= =?utf-8?B?cFhmbllHdmdxODRKdVExNUxTa1l3ZjNud3ZHWUJBMmJFcS9NUEhveE9DMHZY?= =?utf-8?B?WEk3QldSVEpSVFBlVVBEWjB0Tk1qaVc3MU5iMEhXY2M1NlRGcXMvVmRpdGdU?= =?utf-8?B?NVJZakVkQW9CQ1c0L05NTkpGb0wxd1Z0Y2NNVGMvWWtPeHpZbkpJMDdZcnlv?= =?utf-8?B?enIwVWhDTEhXd1gxWDlrLytiUHVJcUJQWVMzWWIxcGdpUkRqVDVRd1FkUmZa?= =?utf-8?B?c01wM2luTDNPY0I4OUZmY3JDN2NnTE9RZzViZ082NkZaUlVsQWlYSjBUajlD?= =?utf-8?B?T3NlTWRtUzR6QXkvYTRzZW9YMmFMaUVwaTBRNWl4NHdWM3YrQi9LTVNFM2lQ?= =?utf-8?B?dVIvbis5b29INGRweTAxOWZYV1g3dCtpUWxaNUVxaGFGY1M5c00wWUxRemww?= =?utf-8?B?aVJJNGFObzJYb2I0Zm9NYldJRlA1K0JKNlZYeXFFWlhDV1ZBS3RGOUdMRUpk?= =?utf-8?B?RjEwbTdLdGdNdFd0U2tNUHRGOFF6L1hsRG5tOGVaS2xoalF2dkJvZW4ra2du?= =?utf-8?B?ZUdjei92KzFOWmZIU2RWMC9UNTdWS29FcUV4UGdWSUNHeHdVQWIzL21jV1RK?= =?utf-8?B?ZktpTFNxclU2Y3lTOGZ2eElFdWZMa1NkcDNiSy9KY3JneStXN1JSVEVZSmlj?= =?utf-8?B?OEtBQ3NURVV2M0JLYTR1Z1FUSThzV1FCOTI5cmM5UnhWUmJidDUwWTZnR1ky?= =?utf-8?B?am9ab1A3TVo3elIzQ29qcmVSdk0yYlZLd1daQzRnM1Y0NHBTV0VqSC9GQ2Ey?= =?utf-8?B?MEhKMFdWamsvdHJsWFJYNUZCaEJaaU94NjlibWJPMWNBLzY2MUdDY2FNbzRC?= =?utf-8?B?UWJqMHlnTkFKaWJ5NVNxVmVkK2tNVldPUmQyNXNDZmtUaHBJMzY2dXVPQnpR?= =?utf-8?B?UUs3bEEwYzhZNWdZWlc5LzJzZTI5aC9qaXdLZjk4Z3JGeXJzVWI2UWUxNGtO?= =?utf-8?B?bDBrblRwakhObHdZVVZwbEFsK1ZzYjM4dFZqMktzV0ZkYW12VThPMVJUZGtQ?= =?utf-8?B?cThUYytZd3ZtanN3K1JrZHBObUFIYnFLN2YrSHRjOVh1SWsyVmZQcnM5VnFB?= =?utf-8?B?b2pKRWwwdjhpdzQxeVRMeTYvVUlTWDIxUDEvZU5VM0NPM0JaS21RNHd4OFlz?= =?utf-8?B?b2FSRndHNXlYcTdzZkdKVG9aTjlndFRYTkFGS2hVeHZ2b0tRNUI1eTNsUU01?= =?utf-8?B?M0FOa05KWkRjQjgxV0RHSlBESlhJM3JWNmpkN0Vnb3JKM3Nqd2hZbzE0cU4v?= =?utf-8?B?S25tcGdBcld4NU9pQ0xYQ0ZtRENtTFVtVFJLc0krMjF6ejI4a2lJbmovNnNX?= =?utf-8?B?a2Y5NGlsaHd0SkFTeGJyVU1Dejd6TnVVM0tGRkFscVRkVmhQblB2U09vazB1?= =?utf-8?B?dWpaaFlHaFdRY1pYd2xpaU1QUHphaGtRSGdrMHB3NC9qdWZJVHlheGQ0K3pl?= =?utf-8?B?cGd5UzQzSWlmRlV1SG5XbDdQSENMSlJUK3BYMGd3N0d5U0NGV3pTRU5OQmV6?= =?utf-8?B?UWEyR2xwNjdOUzVJOW9uYnlzQkpPNDF6MGNVSHdqWDQyWTE1L0Z3N09NYTdx?= =?utf-8?B?TzBrNXVFbnNmK3BPUGVLMWpQQ1hqanArWWw0SGJ4ZGdlOTBCNUFtU1ZwdmVp?= =?utf-8?B?NWtmNldiT3NwTjZacThGNWt6eUxpTitDaFZmaE9qaTJEWGtFQUJjUE5vaTQr?= =?utf-8?B?dnFMcEQvNU9WbmhUZE1TOUJaS0ZldEJ0NURpcGlBZDZxOFZXZ1BzSWY3YW85?= =?utf-8?B?cUtqTHNXL3J2dUFxZ2Z4T1dvQ1hiL1hzelVVVjZhSW9VVm5ZL0pMSGx6YjEz?= =?utf-8?B?N0JhWmVmVHk1Q1N6WTAyaVFhRm9iVFYyWEtzS3ZwRkk1L3AzK0k3clRnWW05?= =?utf-8?B?NVJSdzFjTFZIbWNzOWVnVUJtYUhmVUpBZnFqdW5UWGtQL0J0ZnB3T2Z4WDFl?= =?utf-8?B?ejFLZ3Y1dUo3T3FzYjAzVmpISnNUTGJDTFplMTZSUHBaRTdqdGwyb2gxZDJC?= =?utf-8?B?Unc0VUVpaWpDdzl2Yi9wYXg4NUNnWGt0djV5TnB5MEs4QkZxVmdtSEkrUUtM?= =?utf-8?B?RlJWYXpubmVsVTlFeWZtdHJCK3pNeDJIeU5vUzltVW1pSE1lalF1QT09?= X-OriginatorOrg: citrix.com X-MS-Exchange-CrossTenant-Network-Message-Id: b9d28a8f-7224-4980-8e2f-08de5d1b9a7a X-MS-Exchange-CrossTenant-AuthSource: CH8PR03MB8275.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 26 Jan 2026 20:43:47.0964 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 335836de-42ef-43a2-b145-348c2ee9ca5b X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: 9KntVvmfMLJ4t8lFJEX6gnICv0d7Fxl+c41HjUj44t+M54fRrkTJ1H5O0dsgPFxoxpRECCNLluBR36tx5wKANhhGKn+Qy5qOurFo1n7H1EE= X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS0PR03MB8296 On 26/01/2026 8:41 pm, Ryusuke Konishi wrote: > On Tue, Jan 27, 2026 at 5:22 AM Andrew Cooper wrote: >> On 26/01/2026 7:54 pm, Borislav Petkov wrote: >>> On Tue, Jan 27, 2026 at 04:07:04AM +0900, Ryusuke Konishi wrote: >>>> Hi All, >>>> >>>> I am reporting a boot regression in v6.19-rc7 on an x86_32 >>>> environment. The kernel hangs immediately after "Booting the kernel" >>>> and does not produce any early console output. >>>> >>>> A git bisect identified the following commit as the first bad commit: >>>> b505f1944535 ("x86/kfence: avoid writing L1TF-vulnerable PTEs") >>> I can confirm the same - my 32-bit laptop experiences the same. The guest >>> splat looks like this: >>> >>> [ 0.173437] rcu: srcu_init: Setting srcu_struct sizes based on contention. >>> [ 0.175172] ------------[ cut here ]------------ >>> [ 0.176066] kernel BUG at arch/x86/mm/physaddr.c:70! >>> [ 0.177037] Oops: invalid opcode: 0000 [#1] SMP >>> [ 0.177914] CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.19.0-rc7+ #1 PREEMPT(full) >>> [ 0.179509] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 >>> [ 0.181363] EIP: __phys_addr+0x78/0x90 >>> [ 0.182089] Code: 89 c8 5b 5d c3 2e 8d 74 26 00 0f 0b 8d b6 00 00 00 00 89 45 f8 e8 08 a4 1d 00 84 c0 8b 55 f8 74 b0 0f 0b 8d b4 26 00 00 00 00 <0f> 0b 8d b6 00 00 00 00 0f 0b 66 90 8d 74 26 00 2e 8d b4 26 00 00 >>> [ 0.185723] EAX: ce383000 EBX: 00031c7c ECX: 31c7c000 EDX: 034ec000 >>> [ 0.186972] ESI: c1ed3eec EDI: f21fd101 EBP: c2055f78 ESP: c2055f70 >>> [ 0.188182] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 EFLAGS: 00210086 >>> [ 0.189503] CR0: 80050033 CR2: ffd98000 CR3: 029cf000 CR4: 00000090 >>> [ 0.191045] Call Trace: >>> [ 0.191518] kfence_init+0x3a/0x94 >>> [ 0.192177] start_kernel+0x4ea/0x62c >>> [ 0.192894] i386_start_kernel+0x65/0x68 >>> [ 0.193653] startup_32_smp+0x151/0x154 >>> [ 0.194397] Modules linked in: >>> [ 0.194987] ---[ end trace 0000000000000000 ]--- >>> [ 0.195879] EIP: __phys_addr+0x78/0x90 >>> [ 0.196610] Code: 89 c8 5b 5d c3 2e 8d 74 26 00 0f 0b 8d b6 00 00 00 00 89 45 f8 e8 08 a4 1d 00 84 c0 8b 55 f8 74 b0 0f 0b 8d b4 26 00 00 00 00 <0f> 0b 8d b6 00 00 00 00 0f 0b 66 90 8d 74 26 00 2e 8d b4 26 00 00 >>> [ 0.200231] EAX: ce383000 EBX: 00031c7c ECX: 31c7c000 EDX: 034ec000 >>> [ 0.201452] ESI: c1ed3eec EDI: f21fd101 EBP: c2055f78 ESP: c2055f70 >>> [ 0.202693] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 EFLAGS: 00210086 >>> [ 0.204011] CR0: 80050033 CR2: ffd98000 CR3: 029cf000 CR4: 00000090 >>> [ 0.205235] Kernel panic - not syncing: Attempted to kill the idle task! >>> [ 0.206897] ---[ end Kernel panic - not syncing: Attempted to: kill the idle task! ]--- >> Ok, we're hitting a BUG, not a TLB flushing problem. That's: >> >> BUG_ON(slow_virt_to_phys((void *)x) != phys_addr); >> >> so it's obviously to do with the inverted pte. pgtable-2level.h has >> >> /* No inverted PFNs on 2 level page tables */ >> >> and that was definitely an oversight on my behalf. Sorry. >> >> Does this help? >> >> diff --git a/arch/x86/include/asm/kfence.h b/arch/x86/include/asm/kfence.h >> index acf9ffa1a171..310e0193d731 100644 >> --- a/arch/x86/include/asm/kfence.h >> +++ b/arch/x86/include/asm/kfence.h >> @@ -42,7 +42,7 @@ static inline bool kfence_protect_page(unsigned long addr, bool protect) >> { >> unsigned int level; >> pte_t *pte = lookup_address(addr, &level); >> - pteval_t val; >> + pteval_t val, new; >> >> if (WARN_ON(!pte || level != PG_LEVEL_4K)) >> return false; >> @@ -61,7 +61,8 @@ static inline bool kfence_protect_page(unsigned long addr, bool protect) >> * L1TF-vulnerable PTE (not present, without the high address bits >> * set). >> */ >> - set_pte(pte, __pte(~val)); >> + new = val ^ _PAGE_PRESENT; >> + set_pte(pte, __pte(flip_protnone_guard(val, new, PTE_PFN_MASK))); >> >> /* >> * If the page was protected (non-present) and we're making it >> >> >> >> Only compile tested. flip_protnone_guard() seems the helper which is a >> nop on 2-level paging. >> >> ~Andrew > Yes, after applying this, it started booting. > Leaving aside the discussion of the fix, I'll just share the test > result for now. Thanks.  I'll put together a proper patch. ~Andrew