From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from DU2PR03CU002.outbound.protection.outlook.com (mail-northeuropeazon11011060.outbound.protection.outlook.com [52.101.65.60]) (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 CE4DF3CEBB6; Thu, 19 Mar 2026 12:31:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=52.101.65.60 ARC-Seal:i=3; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773923472; cv=fail; b=tbdSskdSlvEPsoahgZYsN/KwcH8W780SlB/Tv6oy4ph1wXsOqpPM/wdnjlgedegJKXItT8ValWtOtzSWaK8Te2xO1KkxAZV5I4ycEoyk3deUR+ePfU/GaAKp8HiuuK3Zkvb8497kLhARVUnwPzpiH8JgsjydQvId0e4w6kw9ctc= ARC-Message-Signature:i=3; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773923472; c=relaxed/simple; bh=DlVXbq0BYJRAi/n4CPwsa4B5ZK6E+9cC1TO/yIbxEdU=; h=Message-ID:Date:Cc:Subject:To:References:From:In-Reply-To: Content-Type:MIME-Version; b=IfVlnHKLmDDswjLoS2E7zaqjenZQ6RvwQoeAf5rOVtSLOgQrSipE/Pb8DPhzf9p4A5IWrh0T59WZA0eMSQKxKFztsO+LqMm4JP8P7sXHAeWHawqmdQ7Z2Vp1X97gWLIR9cqOkjLYDnTCN2LFHvbslwJBBO3+X6TcHmZjxYVoXhw= ARC-Authentication-Results:i=3; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=Y+8lRa0F; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=Y+8lRa0F; arc=fail smtp.client-ip=52.101.65.60 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="Y+8lRa0F"; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="Y+8lRa0F" ARC-Seal: i=2; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=pass; b=KWBPTUNrFbpiwwSgWxvjSY70l7UKCv2tCrHbt5Tn6EElO8aafkQ/kH/hKcJavYR25dBehYYhr+6eUPKNmDFHQa3LJ0a2ifsR7TN0YGFM0h+XCrWAdc2NjxEqKOxqK8EYmcaWQl12wOOGcvVOAWrHeZWYhQkRQV/xiywcuyoVRx3RsqGKyABuXf9plp2LpOdzNcPmtLAJUOZ7lUO9vP4aUVtdnH8XtNHRtezVKbu4VhW8/JiwQw8jCkj8cBQVDBAID23ROfODwR1gcAHByxE52dQjpr8L7EKbI9s7kgQDsP3IlBkhJO6XR32vFKcg26SKUnWvn1M3XqiTzhoUCYqmyg== ARC-Message-Signature: i=2; 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=l/dtdQKMb2powt8ohLAhmVxBxHzafOxTgDy3QfUIa0g=; b=Luc8OM/eXW+q0GEpWoHFi9WPxyaceyDK0w6F2eKrNXIfFOCw3IvbMvvmDSjxJsCOkEE67FAsvgWvM3NLkXx2SmxOaZ3RquO+AeE3ZzZoyISpuvxmE1U/W7TgN1JQj8DAGhnlZZusrsrJy7s+u2HEwcYtztYlwq+BIzXaPeBq44Fw0pMOkeD4nydV6XpVF1wmtFuCZj5IlYAw6jDOpSeN5GqcG8tMLJQTo7GlrmT9W5POVEAR3ToA4fYNEKC07FINVfFHZQCFbxlu5UYfMj5b/q2yvx3z+uzu7URtInaZr5YoHlBh7OcNChl7QZP6gzhNUJ9Bu41x5VoVUpcVQktEpQ== ARC-Authentication-Results: i=2; mx.microsoft.com 1; spf=pass (sender ip is 4.158.2.129) smtp.rcpttodomain=arndb.de smtp.mailfrom=arm.com; dmarc=pass (p=none sp=none pct=100) action=none header.from=arm.com; dkim=pass (signature was verified) header.d=arm.com; arc=pass (0 oda=1 ltdi=1 spf=[1,1,smtp.mailfrom=arm.com] dkim=[1,1,header.d=arm.com] dmarc=[1,1,header.from=arm.com]) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arm.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=l/dtdQKMb2powt8ohLAhmVxBxHzafOxTgDy3QfUIa0g=; b=Y+8lRa0FBYJum7yPiHoPwV38mLzhA5APlACaq41N6o909qux+xL08yuBNFhRlM336EntAkg4i6XEIMg4UGopkIVKIh+BWW+p/6HIj+vBTpGoO1FeTLAALh/W8xohLnpXos5VoYmBYD4t6pDqZ9ilNN0s1p78JkbwVMKQlmQnS+A= Received: from DB8PR04CA0029.eurprd04.prod.outlook.com (2603:10a6:10:110::39) by DB3PR08MB10336.eurprd08.prod.outlook.com (2603:10a6:10:43b::10) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9723.19; Thu, 19 Mar 2026 12:31:04 +0000 Received: from DU2PEPF00028D02.eurprd03.prod.outlook.com (2603:10a6:10:110:cafe::94) by DB8PR04CA0029.outlook.office365.com (2603:10a6:10:110::39) with Microsoft SMTP Server (version=TLS1_3, cipher=TLS_AES_256_GCM_SHA384) id 15.20.9723.19 via Frontend Transport; Thu, 19 Mar 2026 12:31:04 +0000 X-MS-Exchange-Authentication-Results: spf=pass (sender IP is 4.158.2.129) smtp.mailfrom=arm.com; dkim=pass (signature was verified) header.d=arm.com;dmarc=pass action=none header.from=arm.com; Received-SPF: Pass (protection.outlook.com: domain of arm.com designates 4.158.2.129 as permitted sender) receiver=protection.outlook.com; client-ip=4.158.2.129; helo=outbound-uk1.az.dlp.m.darktrace.com; pr=C Received: from outbound-uk1.az.dlp.m.darktrace.com (4.158.2.129) by DU2PEPF00028D02.mail.protection.outlook.com (10.167.242.186) with Microsoft SMTP Server (version=TLS1_3, cipher=TLS_AES_256_GCM_SHA384) id 15.20.9723.19 via Frontend Transport; Thu, 19 Mar 2026 12:31:04 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=WwlkCE50rmCfNp6zbXQzHYUuPv3cX3H8OrRGPq720/YvdRqslvQnXqbkwwmcvQ9mWKnrRz2Hw0TJ3yc4NDO9Y1teZse1yhdAiBfu+zbPsMj02ejG3foboLmt2ge8mCznsuHi/6Xa8dYwrD4Ynye31fGmhatVwodPOJd+NH69Md/SCMXN7clAClGPkTZ4VxiqQHYYmhBRSEu+MaxkaggbU53ABudsfbLUpNhd4XXqrzz+YjRzFXcLNucWKLgAFZkpbWAl1ETnfSX6+JwITa9VbV97c3HNYF+6ZVRO5zoQHo06G3faW2yfuEtH6vYHeTys9gLyEdH5UAmEe1QJV3kqqA== 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=l/dtdQKMb2powt8ohLAhmVxBxHzafOxTgDy3QfUIa0g=; b=XZxVmWfUQMp+gLlOhCimNdFxGeCO6cUKWY8+0nN0MNbrWr6zD6Q5zOeCXlXosK7XlpwGX6WM2Bx5q/i6ELuygw90TqBYaqBKNGWufq41HrVGzjTQKcq6WlCNQsyB1o6iz6W2RfATopaqNCrXJbdS3Xxq4i338uQUp9FMgJRv9bWLnzXlX+h/Dz/IvTgd91s0IR63PHHzAb3oX3ZINiaJlFE/LXBAKoVI/eCneGDxLwP4EuW42aBZVPg9vWIaewUHJSHVAIVlxp4htTGIF0k/awHU5ZUHTaZz3L5AC7As8GvuJutN3AAEgIIwMhe99B0+q2gnHStyjp8Bf9w/zeHqVw== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=arm.com; dmarc=pass action=none header.from=arm.com; dkim=pass header.d=arm.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arm.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=l/dtdQKMb2powt8ohLAhmVxBxHzafOxTgDy3QfUIa0g=; b=Y+8lRa0FBYJum7yPiHoPwV38mLzhA5APlACaq41N6o909qux+xL08yuBNFhRlM336EntAkg4i6XEIMg4UGopkIVKIh+BWW+p/6HIj+vBTpGoO1FeTLAALh/W8xohLnpXos5VoYmBYD4t6pDqZ9ilNN0s1p78JkbwVMKQlmQnS+A= Authentication-Results-Original: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=arm.com; Received: from AM6PR08MB3414.eurprd08.prod.outlook.com (2603:10a6:20b:49::10) by DBBPR08MB10772.eurprd08.prod.outlook.com (2603:10a6:10:53c::5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9723.19; Thu, 19 Mar 2026 12:30:01 +0000 Received: from AM6PR08MB3414.eurprd08.prod.outlook.com ([fe80::dde8:bf0b:1dc:2a2]) by AM6PR08MB3414.eurprd08.prod.outlook.com ([fe80::dde8:bf0b:1dc:2a2%4]) with mapi id 15.20.9632.017; Thu, 19 Mar 2026 12:30:01 +0000 Message-ID: <6f9ee2d8-7906-4051-bc30-44823e2b2133@arm.com> Date: Thu, 19 Mar 2026 12:29:59 +0000 User-Agent: Mozilla Thunderbird Cc: usama.anjum@arm.com, Arnd Bergmann , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , Kees Cook , Andrew Morton , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Uladzislau Rezki , linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrey Konovalov , Marco Elver , Vincenzo Frascino , Peter Collingbourne , Catalin Marinas , Will Deacon , david.hildenbrand@arm.com Subject: Re: [PATCH 2/3] fork: skip MTE tagging for kernel stacks To: Ryan Roberts References: <20260319114952.3241359-1-usama.anjum@arm.com> <20260319114952.3241359-3-usama.anjum@arm.com> From: Muhammad Usama Anjum Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-ClientProxiedBy: LO4P302CA0024.GBRP302.PROD.OUTLOOK.COM (2603:10a6:600:2c1::10) To AM6PR08MB3414.eurprd08.prod.outlook.com (2603:10a6:20b:49::10) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-TrafficTypeDiagnostic: AM6PR08MB3414:EE_|DBBPR08MB10772:EE_|DU2PEPF00028D02:EE_|DB3PR08MB10336:EE_ X-MS-Office365-Filtering-Correlation-Id: 30d1e15b-9ea5-48dd-c1a7-08de85b36336 x-checkrecipientrouted: true NoDisclaimer: true X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam-Untrusted: BCL:0;ARA:13230040|376014|7416014|366016|1800799024|22082099003|56012099003|18002099003; X-Microsoft-Antispam-Message-Info-Original: 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 X-Forefront-Antispam-Report-Untrusted: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:AM6PR08MB3414.eurprd08.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(376014)(7416014)(366016)(1800799024)(22082099003)(56012099003)(18002099003);DIR:OUT;SFP:1101; X-Exchange-RoutingPolicyChecked: mP2kzuaEfNzMzHI5bRmVKZ++ldI4dHAr/nfbKMYBtPA1lgOhHJf15YaOSUU6/HU9W8tvcgRyIexLweZiKx081mDRYix3x0oiXf4Blk2oGt10XPoie4NwTp3oz/K+NhwmWOzFRK6mNd/XqkUsynhpWT5E0U2xNt6TMZMmu+2NBRYYdohw+ZF6yGgDFndBVUYkRPd/+AImQ/po4sVgzNMwFDcUkqL1LwTJ6xveIQn8zdVIBm1mKPEjqgimmbeifj8GpzhdeszDbYAlyqJL69Wuwy1E7jh28FQRREM3ksUG9mLb4E2dZOmmxWUZzzE+wEs+8rEMbXqbvPu+1qQVHtyQBg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DBBPR08MB10772 X-EOPAttributedMessage: 0 X-MS-Exchange-Transport-CrossTenantHeadersStripped: DU2PEPF00028D02.eurprd03.prod.outlook.com X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id-Prvs: f3fa6dff-7589-4513-313e-08de85b33d76 X-Microsoft-Antispam: BCL:0;ARA:13230040|35042699022|14060799003|36860700016|7416014|376014|1800799024|82310400026|22082099003|18002099003|56012099003; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:4.158.2.129;CTRY:GB;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:outbound-uk1.az.dlp.m.darktrace.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(35042699022)(14060799003)(36860700016)(7416014)(376014)(1800799024)(82310400026)(22082099003)(18002099003)(56012099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: PBhuHUTRR0k9m3a4ZSNZ69XDkEpZvu2nV4wrdX/Qu2KyZY6Xcdzx4Mloei4K13a/UVdkJO8iKo1leL8zL26Ag0RJ1QzzNeRE1efqg0Iun8LkOvYhwWg77q+nV4eOFRQOZsZPS9ZncpMNZLzluEFUjGX7OLeYEgSNjGjGgQ+h8RLlBwEQWkSThkfEvOEmLVEnAIZkbzqqW02UMjMNanWI7UdH45/A4mObvEkBOlhReKWy5IU4Cz9scwOKR90qSrVMpqWa6O/a9SkyvcjUH+oDzob3wvUPZ2BNHO+W/vCOSMJ6Mff2fbhA1hfJTTrKhjHXJkwXCQ50T/MuFOLN4QeOAw+uI9DulatbhvHMCSdAkSwUzEPO6mj6ejvjZOx3tC4ZOopiFiH0HViD4Q/dbrmDJJDoJXRjMJWDV3v1fOHtJWil7sGqgIPCWkXr2Gr5uxzF X-OriginatorOrg: arm.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 19 Mar 2026 12:31:04.0971 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 30d1e15b-9ea5-48dd-c1a7-08de85b36336 X-MS-Exchange-CrossTenant-Id: f34e5979-57d9-4aaa-ad4d-b122a662184d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=f34e5979-57d9-4aaa-ad4d-b122a662184d;Ip=[4.158.2.129];Helo=[outbound-uk1.az.dlp.m.darktrace.com] X-MS-Exchange-CrossTenant-AuthSource: DU2PEPF00028D02.eurprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DB3PR08MB10336 Hi Ryan, Thank you for the review. On 19/03/2026 12:09 pm, Ryan Roberts wrote: > On 19/03/2026 11:49, Muhammad Usama Anjum wrote: >> The stack pointer always uses the match-all tag, so MTE never checks >> tags on stack accesses. Tagging stack memory on every thread creation >> is pure overhead. >> >> - Pass __GFP_SKIP_KASAN in gfp_mask for vmalloc-backed stacks so the >> vmalloc path skips HW tag setup (see previous patch). >> - For the cached VMAP reuse path, skip kasan_unpoison_range() when HW >> tags are enabled since the memory will only be accessed through the >> match-all tagged SP. >> - For the normal page allocator path, pass __GFP_SKIP_KASAN directly >> to the page allocator. >> >> Signed-off-by: Muhammad Usama Anjum >> --- >> kernel/fork.c | 8 +++++--- >> 1 file changed, 5 insertions(+), 3 deletions(-) >> >> diff --git a/kernel/fork.c b/kernel/fork.c >> index bb0c2613a5604..2baf4db39b5a4 100644 >> --- a/kernel/fork.c >> +++ b/kernel/fork.c >> @@ -345,7 +345,8 @@ static int alloc_thread_stack_node(struct task_struct *tsk, int node) >> } >> >> /* Reset stack metadata. */ >> - kasan_unpoison_range(vm_area->addr, THREAD_SIZE); >> + if (!kasan_hw_tags_enabled()) >> + kasan_unpoison_range(vm_area->addr, THREAD_SIZE); >> >> stack = kasan_reset_tag(vm_area->addr); >> >> @@ -358,7 +359,7 @@ static int alloc_thread_stack_node(struct task_struct *tsk, int node) >> } >> >> stack = __vmalloc_node(THREAD_SIZE, THREAD_ALIGN, >> - GFP_VMAP_STACK, >> + GFP_VMAP_STACK | __GFP_SKIP_KASAN, > > Perhaps cleaner to include __GFP_SKIP_KASAN in GFP_VMAP_STACK ? Yes, it would be much better and the correct way. I'll add it in the next version. > >> node, __builtin_return_address(0)); >> if (!stack) >> return -ENOMEM; >> @@ -410,7 +411,8 @@ static void thread_stack_delayed_free(struct task_struct *tsk) >> >> static int alloc_thread_stack_node(struct task_struct *tsk, int node) >> { >> - struct page *page = alloc_pages_node(node, THREADINFO_GFP, >> + struct page *page = alloc_pages_node(node, >> + THREADINFO_GFP | __GFP_SKIP_KASAN, > > I think there are some other places that could benefit from __GFP_SKIP_KASAN; > see arm64's arch_alloc_vmap_stack(), which allocates stacks for efi, irq and > sdei. I think these are allocated at boot, so not really performance sensitive, > but we might as well be consistent? > > You've also missed the alloc_thread_stack_node() implementation for !VMAP when > PAGE_SIZE > STACK_SIZE. > > All of these sites use THREADINFO_GFP so perhaps it is better to just define > THREADINFO_GFP to include __GFP_SKIP_KASAN ? Yes, it'll be the straight forward and clean approach. I'll update. > > Thanks, > Ryan > > >> THREAD_SIZE_ORDER); >> >> if (likely(page)) { >