From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=209.127.230.114 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793758905; b=1gNB4b5jhoONKQQxqgGgRv9NdjfhF//rR1A/93mr+oxM83Gj1NgrQEnJvmqOrlHxg2X2 tILxeifuYRdorDdDEAicp3uNyonrPmfcgghh01IqwZ1ASAKpFrH6hFZI6sfvFpWQFLxQw qQIFEw3oJ/FTflGXcyhWop/53hyiF6kULcjmGEoTluHDWdWlC2zPSTCvROuLFRu7RHDOx nkpjn1bZRnu6bmT/MWJWnd6LwGhVkaB7NSpNB0HODfSzON9qbw4aFz7uPlbdPrGAVXM+v fAnplNfJL/xJsq3Ha+TmId7MO1OGtZqUnMnEssjXLq3TMw+CXN4wV60zTU85RflwzJw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793758905; h=DMARC-Filter:DKIM-Signature:Subject:Message-Id:User-Agent: X-Original-From:X-Lms-Return-Path:Cc:Date:Mime-Version:To:From: References:Content-Type:Content-Transfer-Encoding:In-Reply-To; bh=No6e7FX1QyMHXiq5uSkrdQU3PoMJKwFtYVvKfbAY2G0=; b=PM0OVJUK6c3O+7NkzC0crBkrftKYxY8uboPNIunq6YhlvXkdFMlEYMNfCcqpF9WVtDWb MctMuj4GBjU6slGu7ecRcvVpIrCXjfBxRvTHtB3l/k+tYeS5K8SfyG4HIOEDcU9QsD1hD SsLbWs3Oj5UUnOeg1EXVTMxx3GFE+hhKvKBW47QcJ2FSDXPspP2vDCRt0MQmSl4zJU2hG Kem/sDIbCQMOMNb17poR0iw65QjOwo/UDbq2qEUKnhuCR7alUsGLYCKJBUhEjR6feaNLC SCHLomYakezWkHwjQj30BVqLhTxqYd1LS6+mzIdKlxqteuTPgFqU5OsichMe9juP12w== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=bytedance.com; spf=pass smtp.mailfrom=bytedance.com; dkim=pass header.d=bytedance.com header.i=@bytedance.com header.a=rsa-sha256 header.s=2212171451 header.b=AfRgpS1b; arc=none smtp.remote-ip=209.127.230.114 Received: from va-1-114.ptr.blmpb.com (va-1-114.ptr.blmpb.com [209.127.230.114]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 67CC1606A31B for ; Wed, 4 Nov 2026 02:21:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 67CC1606A31B Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=bytedance.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bytedance.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=bytedance.com header.i=@bytedance.com header.a=rsa-sha256 header.s=2212171451 header.b=AfRgpS1b DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; s=2212171451; d=bytedance.com; t=1793758899; h=from:subject: mime-version:from:date:message-id:subject:to:cc:reply-to:content-type: mime-version:in-reply-to:message-id; bh=No6e7FX1QyMHXiq5uSkrdQU3PoMJKwFtYVvKfbAY2G0=; b=AfRgpS1bnIQW2x4jiAUjh8Zh2/fcYgU7xYeZpJKEwAQSOPhObCagEaIT4YK9SQ7NOmGOAJ 88h2qDnnpwBcM4dltjgF/C0HZC3JPB3hfK+XKETsl6hakGuqJWHOF4kR94b1GIkwamrZOX fzgONbX9d/lCYkU49iwMh/e2jx/R91Auboh+Lb1arCz8d5vXLHGG7ecob0lkaFHAM9lRI+ 0Y8NwZnuo6o1Y68VxJ8WrG28nA32Lcz+h7syyi3z60dOp/i3n3denoYIW3UQpWLT1lKnLO +971rSQK608SCrI4HaI9k6ui6e0b1TSlSlGfwFzdI67DdsU8ayt/JRRqbZdJGA== Subject: Re: [PATCH] arm64: mm: validate /dev/mem mmap ranges without overflow Message-Id: <3d26a89a-7fa2-4daa-a919-82708410d104@bytedance.com> User-Agent: Mozilla Thunderbird X-Original-From: Zhao Gongyi X-Lms-Return-Path: Cc: "Will Deacon" , "Mark Rutland" , , Date: Wed, 4 Nov 2026 10:21:24 +0800 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list Mime-Version: 1.0 To: "Catalin Marinas" From: "Zhao Gongyi" References: <20261101171030.87343-1-zhaogongyi@bytedance.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit In-Reply-To: Hi Catalin, On 11/3/26 11:08 PM, Catalin Marinas wrote: > > Can we write this as: > > int valid_mmap_phys_addr_range(unsigned long pfn, size_t size) > { > phys_addr_t limit = PHYS_MASK + 1; > > return size <= limit && pfn <= (limit - size) >> PAGE_SHIFT; > } > > It would resemble the generic __access_ok() better where we need to > check for similar overflow. I find it easier to read. > > (happy to make the change when applying) > Thanks, your version is clearer. Please feel free to make the change when applying. Thanks, Gongyi