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Bug 158685 - VIA KT133A 686B quirk_vialatency() no longer enough to avoid data corruption
Summary: VIA KT133A 686B quirk_vialatency() no longer enough to avoid data corruption
Alias: None
Product: Fedora
Classification: Fedora
Component: kernel
Version: 3
Hardware: i686
OS: Linux
Target Milestone: ---
Assignee: Alan Cox
QA Contact: Brian Brock
Depends On:
TreeView+ depends on / blocked
Reported: 2005-05-24 20:14 UTC by Alexandre Oliva
Modified: 2007-11-30 22:11 UTC (History)
2 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Last Closed: 2005-10-03 01:10:46 UTC

Attachments (Terms of Use)

Description Alexandre Oliva 2005-05-24 20:14:37 UTC
From Bugzilla Helper:
User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.7.8) Gecko/20050512 Fedora/1.0.4-2 Firefox/1.0.4

Description of problem:
There's a disk server at the uni that started displaying rare disk corruption problems as of some months ago.

The MoBo, an Asus A7V133 with 2 VIA IDE channels and 2 Promise IDE channels, has a known bug that causes disk corruption.  It was possible, however, to minimize the problem through some BIOS settings, and Linux itself gained the ability to remove the problem with quirk_vialatency().

Although I see in dmesg the message that this function prints when it enables the work around, I'm still seeing disk corruption.

Some time ago, I had two big disks in RAID 1 on the VIA channels, holding system images, home dirs, and a small part of a filesystem holding mirrors of external locations such as, and two smaller disks in RAID 1 on the Promise channels, holding the rest of the mirrors filesystem.

As of a few months ago, I started noticing a tendency for rsync to re-fetch big ISO files when I transferred new test releases, after priming the ISOs from our local copy of rawhide.  The re-fetch was because the files didn't match their expected checksums.

After checking that the BIOS settings were correct, and that the BIOS was the latest available, I figured I'd try rearranging the disks a bit.  I added a Sil680 ATA133 RAID controller to the box, moved the smaller disks to it, and moved the bigger disks to the Promise controller.  The problems remained.

But this time I actually looked into the corruption pattern, just to make sure it wasn't memory going bad (we had run a memtest recently, but not for very long, since the box is the main server of the lab)

The corruption pattern I got when copying one big file from the Promise controller to the Sil680 controller was that a pair of 4Kb pages from the original file ended up in two different locations in the copy: the original location, plus another location that, unlike the original, was aligned to an 8Kb boundary.  I.e., the commands:

cmp <(dd if=$copy bs=4k skip=22119 count=2) <(dd if=$orig bs=4k skip=22119 count=2)

cmp <(dd if=$copy bs=4k skip=94534 count=2) <(dd if=$orig bs=4k skip=22119 count=2)

succeeded, whereas this one failed, confirming that the duplicate was not present in the original:

cmp <(dd if=$orig bs=4k skip=94534 count=2) <(dd if=$orig bs=4k skip=22119 count=2)

FWIW, the original failure mode for this VIA quirk I was familiar with was a corruption of 31 bytes out of a 32-byte block, the first byte being correct, the maining being copied from the corresponding locations of another 32-byte block, generally in the file being copied.

Although this could still be a symptom of the same bug, I can't tell for sure.  It might as well have something to do with RAID, page table management, or anything, really :-(

On the good side, I've got a very similar box at home, that also displayed the original quirk problem, and enough disks I could play with to try to trigger the bug myself, but I could use suggestions on what to try.  I haven't observed the problem in the recent past, but then I don't use that box much any more.

Version-Release number of selected component (if applicable):

How reproducible:

Steps to Reproduce:
1.copy a big (100MB+) file across IDE controllers the original with the copy

Actual Results:  They sometimes differ

Expected Results:  They shouldn't

Additional info:

Comment 1 Dave Jones 2005-07-15 20:34:45 UTC
An update has been released for Fedora Core 3 (kernel-2.6.12-1.1372_FC3) which
may contain a fix for your problem.   Please update to this new kernel, and
report whether or not it fixes your problem.

If you have updated to Fedora Core 4 since this bug was opened, and the problem
still occurs with the latest updates for that release, please change the version
field of this bug to 'fc4'.

Thank you.

Comment 2 Dave Jones 2005-10-03 01:10:46 UTC
This bug has been automatically closed as part of a mass update.
It had been in NEEDINFO state since July 2005.
If this bug still exists in current errata kernels, please reopen this bug.

There are a large number of inactive bugs in the database, and this is the only
way to purge them.

Thank you.

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