linux-kernel - Re: Hibernation considerations

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <Pine.LNX.4.64.0707151650090.25614@asgard.lang.hm>
Date:	Sun, 15 Jul 2007 16:53:47 -0700 (PDT)
From:	david@...g.hm
To:	Alan Stern <stern@...land.harvard.edu>
cc:	"Rafael J. Wysocki" <rjw@...k.pl>,
	LKML <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	"Huang, Ying" <ying.huang@...el.com>,
	Jeremy Maitin-Shepard <jbms@....edu>,
	Kyle Moffett <mrmacman_g4@....com>,
	Nigel Cunningham <nigel@...el.suspend2.net>,
	Pavel Machek <pavel@....cz>,
	pm list <linux-pm@...ts.linux-foundation.org>,
	Al Boldi <a1426z@...ab.com>
Subject: Re: Hibernation considerations

On Sun, 15 Jul 2007, Alan Stern wrote:

> On Sun, 15 Jul 2007 david@...g.hm wrote:
>
>>> (1) Filesystems mounted before the hibernation are untouchable
>>>
>>>    When there's a memory snapshot, either in the form of a hibernation image,
>>>    or in the form of the "old" kernel and processes available to the "new"
>>>    kexeced kernel responsible for saving their memory, the filesystems mounted
>>>    before the hibernation should not be accessed, even for reading, because
>>>    that would cause their on-disk state to be inconsistent with the snapshot
>>>    and might lead to a filesystem corruption.
>>
>> AFAIK this is only the case with ext3, all other filesystems could be
>> accessed read-only safely
>>
>> this is arguably a bug with ext3 (and has been discussed as such), but
>> right now the ext3 team has decided not to change this bahavior so
>> hibernate needs to work around it. but don't mistake a work-around for a
>> single (admittedly very popular) filesystem with a hard and fast
>> directive.
>
> Isn't is possible to avoid this problem by mounting an ext3 filesystem
> as readonly ext2?  Provided the filesystem isn't dirty it should be
> doable.  (And provided the filesystem doesn't use any ext3 extensions
> that are incompatible with ext2.)

from the last discussion I saw on the kernel mailing list, no. the act of 
mounting the ext3 filesystem as ext2 read-only will change it as the 
unsupported extentions get turned off (and I think the journal contents at 
least are lost as part of this)

David Lang
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/