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 for Android: free password hash cracker in your pocket
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20081105195713.GB9266@mit.edu>
Date:	Wed, 5 Nov 2008 14:57:13 -0500
From:	Theodore Tso <tytso@....edu>
To:	Solofo.Ramangalahy@...l.net
Cc:	Jindrich Makovicka <makovick@...il.com>, linux-ext4@...r.kernel.org
Subject: Re: data corruption with ext4 (from 2.6.27.4) exposed by rtorrent

On Wed, Nov 05, 2008 at 08:44:32PM +0100, Solofo.Ramangalahy@...l.net wrote:
> Hi Jindrich,
> 
> Jindrich Makovicka writes:
>  > The following testcase was used to trigger the infamous MAP_SHARED
>  > dirty flag bug. Maybe it could be of some help here too:
>  > 
>  > http://lkml.org/lkml/2006/12/27/180
> 
> Thanks for remembering!
> 
> The test case triggers corruption with 2.6.28-rc3 + ext4 patch queue:
> . bunch of errors like
>   Chunk 71637 corrupted (0-1339)  (2756-4095)
>   Expected 213, got 0
>   with default mount.
> . nodelalloc is ok.

It's useful to know that you were able to trigger corruption using the
test case.

How much memory did you have on your system, and how much memory was
free when you ran the test case?  I wasn't able to reproduce it using
the test case, but I have 4 gigs of memory.  One theory which is
currently being kicked around is that it is a combination of delayed
allocation and memory pressure.  Disabling delayed allocation by
mounting with -o nodelalloc does seem to make the problem go away.
The next question is whether the problem is more easily triggerred
when under memory pressure.

						- Ted
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ