From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id ADC0D3C5558; Fri, 10 Apr 2026 18:19:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775845182; cv=none; b=mmJ723svaM76ZO7WjATPHhCyCEqt22UjUfx1ylTyQouQBa1/RwAxhNwJGxtXD/O4hEjO8CD0sfoGKdl2xBT7gQdyShxOfttFqhCwSH0YLe2Yc9r46KHb56/jmGT3NRCeYQNHpM7jF26+05KXnAS/1/PSPBRffIGVXQRxMDPC5+Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775845182; c=relaxed/simple; bh=wswWxxzi+b+e63Bx29Kjg7d6BTWx3Z9Nz5swIjtgDRA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=A51k06YYQCvaRAva8xgmlQhM+vgNVrZM2tZRIIGHtjNJ9lPGaqfwoxQkRzh1PjqbXFFQcJvqBxvnrBFdgnjfXxS3NPB8piPNvFhOsLzSJqCwC2hbW4m9rKrTNQqyapZBQMZA2/X6fGOWz3N1XZ3eok9LCfA8pVBgLvqhVdhJ4v0= ARC-Authentication-Results:i=1; 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=vHnKeGLO; arc=none smtp.client-ip=217.140.110.172 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="vHnKeGLO" Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 687F847E0; Fri, 10 Apr 2026 11:19:34 -0700 (PDT) Received: from arm.com (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 883BA3F632; Fri, 10 Apr 2026 11:19:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1775845180; bh=wswWxxzi+b+e63Bx29Kjg7d6BTWx3Z9Nz5swIjtgDRA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=vHnKeGLObdFUaf8rjfTZjKYDlZJQDObsKUGnOfH7zl8i3+6jMZfRayrZsLLZNgTNi G8xSZJNHssEubmeCoQWD8n/BAHe9gtEZ4r3r1qh6PIPRYd8urfc/JkeCZhZLmm0ioU l1VMeSKcOsZFUhiopVi80bp9UKot3vz5nY0R6UIc= Date: Fri, 10 Apr 2026 19:19:34 +0100 From: Catalin Marinas To: Muhammad Usama Anjum Cc: 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 , Will Deacon , Ryan.Roberts@arm.com, david.hildenbrand@arm.com Subject: Re: [PATCH v2 3/3] mm: skip KASAN tagging for page-allocated page tables Message-ID: References: <20260324132631.482520-1-usama.anjum@arm.com> <20260324132631.482520-4-usama.anjum@arm.com> Precedence: bulk X-Mailing-List: linux-arch@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260324132631.482520-4-usama.anjum@arm.com> On Tue, Mar 24, 2026 at 01:26:29PM +0000, Muhammad Usama Anjum wrote: > Page tables are always accessed via the linear mapping with a match-all > tag, so HW-tag KASAN never checks them. For page-allocated tables (PTEs > and PGDs etc), avoid the tag setup and poisoning overhead by using > __GFP_SKIP_KASAN. SLUB-backed page tables are unchanged for now. (They > aren't widely used and require more SLUB related skip logic. Leave it > later.) > > Reviewed-by: Ryan Roberts > Signed-off-by: Muhammad Usama Anjum Reviewed-by: Catalin Marinas