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 X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 59A7BC43387 for ; Tue, 8 Jan 2019 12:14:55 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 25EF220850 for ; Tue, 8 Jan 2019 12:14:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="btzDEPSO" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 25EF220850 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=Td9WG+lqG6mXXRdsWaniHvDTHTB9CyhXFco4Oce2b1A=; b=btzDEPSOAjF9gB gSMKFQFfEInA3tkgWxCAJN7U01Qy22kY47FUKo1yAJQbC60poxmTQXQANjF+kpXw05aNCmK79Xc06 rcNWGn97ioI/lLlHTfc7JunUEaaroUofFDlTIEF4YxwqD2wdMsbxI3v7M8MjLxoiPpRcEgMXIOlT1 wYc9y0EfBnqrs8eT45yNP/slWTVh2pVOPri+S0lsxBUolkYr3j5drdYDs592tW+I9Ki8aoz/z4ujU nxdm0T4iwtZ7zSHrnLQUH6I8oklIV3oO0lN68YuYg/U3N2kV7U4rDDhviStLRvbFfoOvi50UktqBf 1o1v0Cus22iQwetGLimg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1ggqHT-0002nY-1E; Tue, 08 Jan 2019 12:14:51 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1ggqHP-0002kz-0a; Tue, 08 Jan 2019 12:14:48 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 1D0481596; Tue, 8 Jan 2019 04:14:45 -0800 (PST) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B61413F70D; Tue, 8 Jan 2019 04:14:43 -0800 (PST) Date: Tue, 8 Jan 2019 12:14:41 +0000 From: Mark Rutland To: Miles Chen Subject: Re: [PATCH] arm64: trap illegal translations in __virt_to_phys() Message-ID: <20190108121440.GC29102@lakrids.cambridge.arm.com> References: <1546860080-13027-1-git-send-email-miles.chen@mediatek.com> <20190107150019.GC46743@lakrids.cambridge.arm.com> <1546917883.6754.8.camel@mtkswgap22> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1546917883.6754.8.camel@mtkswgap22> User-Agent: Mutt/1.11.1+11 (2f07cb52) (2018-12-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190108_041447_221071_1E9707C5 X-CRM114-Status: GOOD ( 16.95 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: wsd_upstream@mediatek.com, Catalin Marinas , Will Deacon , linux-kernel@vger.kernel.org, linux-mediatek@lists.infradead.org, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Jan 08, 2019 at 11:24:43AM +0800, Miles Chen wrote: > On Mon, 2019-01-07 at 15:00 +0000, Mark Rutland wrote: > > On Mon, Jan 07, 2019 at 07:21:20PM +0800, Miles Chen wrote: > > > Current __virt_to_phys() only print warning messages for non-linear > > > addresses. It's hard to catch all warnings by those messages. > > > > Why? Are you seeing a large number of warnings somewhere? > > Official kernel works fine. I saw some cases in our internal branch and > we're fixing them. > > > > > > So add a VIRTUAL_BUG_ON() to trap all non-linear and non-symbol > > > addresses (e.g., stack addresses) > > > > > > Tested by pass stack addresses and symbol addresses to __pa(). Result: > > > stack addresses: kernel BUG() > > > > Either: > > > > * Stacks are vmap'd, and __is_lm_address(stack_addr) is false. We'll > > produce a WARNING() today (and return a junk physical address). > > > > * Stacks are linear mapped, and cannot be distinguished from other > > linear mapped addresses. The physical address will be valid. > > > > ... so I don't understand why you need to change this. > > For the first case: for vmap'd stack, __pa() returns a junk > physical address and it might be easier to debug this incorrect address > translation by a BUG() call instead of monitoring the warning log. I think that's an argument for upgrading the existing WARN() to a BUG(), rather than adding a separate VIRTUAL_BUG_ON(). However, there are cases where the junk physical address is not used to perform an access, and the WARN() is more helpful. You can set panic_on_warn to get an immediate panic() when the WARN() fires. Is there some reason that approach doesn't work for you? Thanks, Mark. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel