Re: Reproducible data corruption with sendfile+vsftp - splice regression?

From: Holger Hoffstaette
Date: Sun Dec 02 2007 - 15:55:29 EST


On Sun, 02 Dec 2007 17:00:03 +0100, Holger Hoffstaette wrote:

> On Fri, 30 Nov 2007 10:26:54 -0800, Rick Jones wrote:
>
>> Could the corruption be seen in a tcpdump trace prior to transmission
>> (ie taken on the sender) or was it only seen after the data passed out
>> the NIC?
>
> I did the following:
>
> 1) turn on tso on the server's r8169: ethtool --offload eth0 tso on
> 2) on the server: tcpdump -i eth0 -s 0 -w <file>
> 3) ftp'ed file to 100mbit client
>
> As expected the file was corrupted, and the various corrupted byte
> sequences also show up in the tcpdump file at the corresponding offsets.
>
> I did this with 2.6.22.14, so it does not seem to be a recent regression
> in .23/.24.
>
> All files can be found here:
> http://hoho.dyndns.org/~holger/dist/r8169-tso/
>
> I will gladly try out any other tweaks but need some guidance as I don't
> know what exactly to change - maybe without NAPI for the r8169?

Ta-daa! Rebuilding 2.6.22.14 (and I suspect all other versions) without
NAPI for the r8169 but with tso enabled yields NO data corruption; the
ftp'ed file has a good crc, repeatedly.

Any suggestions how to proceed? Should I file this in bugzilla?

thanks
Holger


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