From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760185Ab3BHQvH (ORCPT ); Fri, 8 Feb 2013 11:51:07 -0500 Received: from terminus.zytor.com ([198.137.202.10]:34225 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758134Ab3BHQvF (ORCPT ); Fri, 8 Feb 2013 11:51:05 -0500 User-Agent: K-9 Mail for Android In-Reply-To: References: <20130205203616.GA8228@fenchurch.internal.datastacks.com> <5111E44C.2040308@zytor.com> <22d54b6d-6342-4826-bb93-c9fc46f2041a@email.android.com> <6b31c4f9-d98c-42fc-a510-39bf536b3299@email.android.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Subject: Re: [RFC 2/2] initramfs with digital signature protection From: "H. Peter Anvin" Date: Fri, 08 Feb 2013 08:50:52 -0800 To: "Kasatkin, Dmitry" CC: Peter Jones , linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Message-ID: <56d80e23-a177-49dd-bb9f-eec4e7775c04@email.android.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Yes, but I am talking about initramfs. "Kasatkin, Dmitry" wrote: >On Fri, Feb 8, 2013 at 5:49 PM, H. Peter Anvin wrote: >> Yes, but you can't umount rootfs. > >But that was not a rootfs, but tmpfs/ramfs mounted to /root folder. > >> >> "Kasatkin, Dmitry" wrote: >> >>>On Wed, Feb 6, 2013 at 6:41 PM, H. Peter Anvin wrote: >>>> The cleanup is not a umount, it is actually a tree walk unlinking >the >>>contents. >>>> >>> >>>Please see that umounting ramfs releases the memory. >>>There was no forced cleanup. >>>"cp" copied about 2GB of content. >>>After umounting we got 2GB back to free RAM... >>> >>>kds@kds:~$ sudo mount -t ramfs testramfs /test >>>kds@kds:~$ sudo cp -r /usr/ /test >>>kds@kds:~$ du -sm /test >>>2154 /test >>>kds@kds:~$ free >>> total used free shared >>>buffers cached >>>Mem: 8058600 7855780 202820 0 24768 >>>4819136 >>>-/+ buffers/cache: 3011876 5046724 >>>Swap: 0 0 0 >>>kds@kds:~$ sudo umount /test >>>kds@kds:~$ free >>> total used free shared >>>buffers cached >>>Mem: 8058600 5644864 2413736 0 25268 >>>2623956 >>>-/+ buffers/cache: 2995640 5062960 >>>Swap: 0 0 0 >>> >>>The same happens also with tmpfs. >>> >>>- Dmitry >>> >>>> "Kasatkin, Dmitry" wrote: >>>> >>>>>On Wed, Feb 6, 2013 at 7:04 AM, H. Peter Anvin >wrote: >>>>>> On 02/05/2013 02:09 PM, Kasatkin, Dmitry wrote: >>>>>>> >>>>>>> >>>>>>> It should not be like that. Actually when pre-init exits, >cleanup >>>>>code >>>>>>> umount tmpfs, which in turn cleanups the RAM. >>>>>>> >>>>>> >>>>>> It doesn't quite... the rootfs is permanent. This is also only >one >>>>>usage >>>>>> mode: there are quite a few Linux systems running directly out of >>>>>initramfs. >>>>>> >>>>> >>>>>rootfs is not permanent when it is ramfs. It is cleaned up on >switch >>>>>root. >>>>>It is easy to find out that it is empty by mounting : mount -t >ramfs >>>>>rootfs /mnt/ >>>>> >>>>>In the case of running from normal storage, of course, there is >>>>>ridicules remove the content. >>>>> >>>>>- Dmitry >>>>> >>>>> >>>>>> -hpa >>>>>> >>>>>> >>>>>> -- >>>>>> H. Peter Anvin, Intel Open Source Technology Center >>>>>> I work for Intel. I don't speak on their behalf. >>>>>> >>>> >>>> -- >>>> Sent from my mobile phone. Please excuse brevity and lack of >>>formatting. >> >> -- >> Sent from my mobile phone. Please excuse brevity and lack of >formatting. -- Sent from my mobile phone. Please excuse brevity and lack of formatting.