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

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

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

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

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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,

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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.?
-- 
Ezequiel Garcia, VanguardiaSur
www.vanguardiasur.com.ar