From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f50.google.com (mail-oi0-f50.google.com [209.85.218.50]) by kanga.kvack.org (Postfix) with ESMTP id 7BCDC6B0253 for ; Mon, 7 Mar 2016 16:02:35 -0500 (EST) Received: by mail-oi0-f50.google.com with SMTP id m82so88581801oif.1 for ; Mon, 07 Mar 2016 13:02:35 -0800 (PST) Received: from mail-ob0-x236.google.com (mail-ob0-x236.google.com. [2607:f8b0:4003:c01::236]) by mx.google.com with ESMTPS id a8si13256991obt.51.2016.03.07.13.02.34 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 07 Mar 2016 13:02:34 -0800 (PST) Received: by mail-ob0-x236.google.com with SMTP id rt7so116985785obb.3 for ; Mon, 07 Mar 2016 13:02:34 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <20160307.155810.587016604208120674.davem@davemloft.net> References: <56DDDA31.9090105@oracle.com> <56DDE783.8090009@oracle.com> <20160307.155810.587016604208120674.davem@davemloft.net> From: Andy Lutomirski Date: Mon, 7 Mar 2016 13:02:14 -0800 Message-ID: Subject: Re: [PATCH v2] sparc64: Add support for Application Data Integrity (ADI) Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: David Miller Cc: Khalid Aziz , Jonathan Corbet , Andrew Morton , dingel@linux.vnet.ibm.com, bob.picco@oracle.com, "Kirill A. Shutemov" , "Aneesh Kumar K.V" , Andrea Arcangeli , Arnd Bergmann , sparclinux@vger.kernel.org, Rob Gardner , Michal Hocko , chris.hyser@oracle.com, Richard Weinberger , Vlastimil Babka , Konstantin Khlebnikov , Oleg Nesterov , Greg Thelen , Jan Kara , xiexiuqi@huawei.com, Vineet.Gupta1@synopsys.com, Andrew Lutomirski , "Eric W. Biederman" , Benjamin Segall , Geert Uytterhoeven , Davidlohr Bueso , Alexey Dobriyan , "linux-doc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , linux-arch , Linux API On Mon, Mar 7, 2016 at 12:58 PM, David Miller wrote: > From: Khalid Aziz > Date: Mon, 7 Mar 2016 13:41:39 -0700 > >> Shared data may not always be backed by a file. My understanding is >> one of the use cases is for in-memory databases. This shared space >> could also be used to hand off transactions in flight to other >> processes. These transactions in flight would not be backed by a >> file. Some of these use cases might not use shmfs even. Setting ADI >> bits at virtual address level catches all these cases since what backs >> the tagged virtual address can be anything - a mapped file, mmio >> space, just plain chunk of memory. > > Frankly the most interesting use case to me is simply finding bugs > and memory scribbles, and for that we're want to be able to ADI > arbitrary memory returned from malloc() and friends. > > I personally see ADI more as a debugging than a security feature, > but that's just my view. The thing that seems awkward to me is that setting, say, ADI=1 seems almost equivalent to remapping the memory up to 0x10...whatever, and the latter is a heck of a lot simpler to think about. -- Andy Lutomirski AMA Capital Management, LLC -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org