EXT4 Data Corruption Bug Hits Stable Linux Kernels

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rokytnji
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EXT4 Data Corruption Bug Hits Stable Linux Kernels

#1 Post by rokytnji »

EXT4 Data Corruption Bug Hits Stable Linux Kernels
Posted by Michael Larabel on October 24, 2012
As a warning for those who are normally quick to upgrade to the latest stable vanilla kernel releases, a serious EXT4 data corruption bug worked its way into the stable Linux 3.4, 3.5, and 3.6 kernel series.

Being discussed recently on the Linux kernel mailing list was an "apparent serious progressive ext4 data corruption bug in 3.6.3." Theodore Ts'o was able to successfully bisect the kernel and found the serious bug, which first appeared within the Linux 3.6.2 kernel and was since back-ported to older stable kernels.

http://www.phoronix.com/scan.php?page=n ... px=MTIxNDQ

read this before panicking though.
It looks like fscking everything will fix it (it'll replay the buggered
journal, mangling the metadata, but then fix up the scrambled metadata
and fix the journal's starting block). So I probably don't need to worry
about latent corruption hiding waiting to pounce. Phew.
https://lkml.org/lkml/2012/10/23/706

I run ext4 file systems on some of my installs but I am not sweating it.

rokytnji
Posts: 2262
Joined: Tue 20 Jan 2009, 15:54

Update

#2 Post by rokytnji »

Update 25-10-12:

Theodore Ts'o has continued his investigation of the bug and has found that the problem was more esoteric than was first thought. The user who reported the problem was using umount -l, which immediately unmounts the filesystem without waiting for it to stop being busy. The bug is now thought to be caused when the machine is being shut down while it is in the process of unmounting the filesystem with an already compromised journal.

The developers are still working to pinpoint the exact problem and it might actually involve more kernel components than just the ext4 drivers. In any case, it has become clear that the bug needs a very specific configuration to surface and is unlikely to affect most users.
http://www.h-online.com/open/news/item/ ... 36110.html

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8-bit
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#3 Post by 8-bit »

How about a frugal install to an ext2 partition and picking an ext3 format for the pupsave file?
Would one be asking for trouble in doing so?

rokytnji
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#4 Post by rokytnji »

8-bit wrote:How about a frugal install to an ext2 partition and picking an ext3 format for the pupsave file?
Would one be asking for trouble in doing so?
Should not be a problem. Only way I know though would be to try it out. The ext4 bug has been fixed by the way.

http://www.phoronix.com/scan.php?page=n ... px=MTIxODY

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sunburnt
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#5 Post by sunburnt »

And the ext4 bug really was very limited in what conditions caused it.


An image file and the partition it`s on have no effect on each other.
Another words, the file system format of each doesn`t effect the other.

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