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=-5.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 E27D7C43331 for ; Thu, 26 Mar 2020 11:33:58 +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 AB31F2070A for ; Thu, 26 Mar 2020 11:33:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="iCLS/GKf" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AB31F2070A 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=G3HCeIP+nr8L1b3Nqy6Ee0SiO+iJUOLBIMXVfmu1xBg=; b=iCLS/GKfJIpA8z s+UcM6Cz/S3RdLUCTQNyxPAQcdsFpxvhkljth6qNqMGS43/pZwLuwoM1Mj+QwbiwBAJTpNE5SJlMz 90l52uj/MaxwFjaxn4BI8GyaBNb4Uzas0qyDft3PnJk68ggBQ7bQYjDV00OwHtPARpeOwgXxkmeGC +dADZwAlteyMJU5JAE+uXr3cFN5VTHGhECv4ABnzZe+XyxjeOAsOuGt38c3rICFgfP5OqrMpKPKcA gdl3SBSnnDbPDOzSTlSKP+2tayxvGY7gkvqiekS1cPDq8rzuNqEFIEVpqB8Pcc2UO1Ffrm2tzkhEb xYb/zrjH+1zoJ0+C6pJg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jHQlp-0001wg-Ge; Thu, 26 Mar 2020 11:33:57 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jHQln-0001vg-E6 for linux-arm-kernel@lists.infradead.org; Thu, 26 Mar 2020 11:33:56 +0000 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 221407FA; Thu, 26 Mar 2020 04:33:53 -0700 (PDT) Received: from mbp (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 48D713F71F; Thu, 26 Mar 2020 04:33:52 -0700 (PDT) Date: Thu, 26 Mar 2020 11:33:49 +0000 From: Catalin Marinas To: Will Deacon Subject: Re: [PATCH] mm/mremap: Add comment explaining the untagging behaviour of mremap() Message-ID: <20200326113349.GB26987@mbp> References: <20200325111347.32553-1-will@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200325111347.32553-1-will@kernel.org> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200326_043355_518795_0ECEFC30 X-CRM114-Status: GOOD ( 10.29 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Linus Torvalds , kernel-team@android.com, linux-kernel@vger.kernel.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 Wed, Mar 25, 2020 at 11:13:46AM +0000, Will Deacon wrote: > Commit dcde237319e6 ("mm: Avoid creating virtual address aliases in > brk()/mmap()/mremap()") changed mremap() so that only the 'old' address > is untagged, leaving the 'new' address in the form it was passed from > userspace. This prevents the unexpected creation of aliasing virtual > mappings in userspace, but looks a bit odd when you read the code. > > Add a comment justifying the untagging behaviour in mremap(). > > Cc: Catalin Marinas > Reported-by: Linus Torvalds > Signed-off-by: Will Deacon I queued this patch via the arm64 tree (for 5.7-rc1). Thanks. -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel