Am 29.05.2015 um 15:07 schrieb Ezequiel Garcia:

On 05/29/2015 03:16 AM, Dr. Uwe Meyer-Gruhl wrote:

quoted

quoted

On Wed, Nov 05, 2014 at 08:39:26AM +0000, Ian Campbell wrote:

quoted

On Tue, 2014-11-04 at 15:20 +0100, Karl Beldan wrote:

quoted

On Sat, Nov 01, 2014 at 12:30:19PM -0300, Ezequiel Garcia wrote:

quoted

Several users ([1], [2]) have been reporting data corruption
with TSO on Kirkwood platforms (i.e. using the mv643xx_eth
driver).

Until we manage to find what's causing this, this simple patch
will make
the TSO path disabled by default. This patch should be queued

for stable,

quoted

quoted

quoted

quoted

fixing the TSO feature introduced in v3.16.

The corruption itself is very easy to reproduce: checkingmd5sum on
a mounted
NFS directory gives a different result each time. Same tests  using
the mvneta
driver (Armada 370/38x/XP SoC) pass with no issues.

Frankly, I'm a bit puzzled about this, and so any ideas ordebugging
hints
are well received.

Hi,

Can you try this :

It fixes things for me, thanks!

Tested-by: Ian Campbell <redacted>

Good thing, thanks for your feedbak Ian !

Karl --

That would be a good thing - although: Neither the patch to disable TSO
altogether nor the one that fixes the underlying problem actually made
it to the official kernel source tree, so it is still present in all
kernels > 3.16 - I just stumbled over this in the current 4.0.4 version.

The fixes in the thread
http://marc.info/?l=linux-netdev&m=141517941900547&w=2 are not
applicable any more to the current driver from the 4.0 kernel, as the
whole respective logic seems to have been changed meanwhile, sadly
without fixing the problem. Disabling TSO completely still works, though.

Can someone in the know please suggest a working fix to the kernel
maintainers, preferably one that does not resort to disable TSO?

Hello Uwe,

Thanks for reporting. There wasn't any patch left behind. The above fix
was merged (and applied to the stable tree) as this commit:

commit 2c2a9cbd64387d6b70ac5db013e9bfe9412c7354
Author: Karl Beldan [off-list ref]
Date:   Wed Nov 5 15:32:59 2014 +0100

     net: mv643xx_eth: reclaim TX skbs only when released by the HW

Can you explain in detail what sort of problem are you running into,
which kernel version are you using, etc.?

Sure, the same kind as had been reported initially.

Background: I have done a Debian port running on an Iomega iConnect (a 
Kirkwood variant).

One of my users reported corrupted data when he used the machine as a 
file and media server over Samba and DLNA. He ruled out any hardware or 
other faults and pointed to my kernel(s). He actually tried versions 
3.18.1 and 4.0.4. However, my kernels are mostly plain vanilla from 
kernel.org without any relevant patches to the code itself. The user 
also found that a kernel 3.14 ran O.K. in the same context.

When I tried, I could just use md5sum on the /usr subtree repeatedly 
without problems locally, but over NFS with the iConnect as a server, I 
had differences on every try in different files each time.

After ruling out network issues as well, it was clear that the NIC 
driver must be the culprit and after a bit of searching which one it 
actually was, I quickly found the messages about the broken TSO feature 
in mv643xx_eth. Then, I tried the suggested fix of "ethtool -K eth0 tso 
off" and voila - the errors are gone. For now, I use a patch to change 
the default to TSO off, but an upstream patch to handle TSO correctly 
would be much better.


Uwe
-- 


-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/pkcs7-signature
Size: 3740 bytes
Desc: S/MIME Cryptographic Signature
URL: <http://lists.infradead.org/pipermail/linux-arm-kernel/attachments/20150529/12a23844/attachment.p7s>