Re: ToDevice error: packet too small (len 0, tailroom 48, need 60), had to copy

can you give me a piece of advice on how to debug this? or how to
see the packet that cause ToDevice this kind of error pls?

On 10/21/11 9:03 PM, Hamid Farhadi wrote:

(sorry to initiate another thread for the same
problem)

Hi,

How to reproduce the error:

1- install Click and OVS

2- make two Taps(tap0, tap1) using OVS and bring them up using
ifconfig. do not do any other OVS config.

3- run this config in kernel mode:

FromDevice(eth0) ->Queue -> Strip(14) ->
EtherEncap(0x0800, eth0 , tap0) -> ToDevice(tap0);

4- send few packets of any kind to eth0

5-CPU goes up and system crashes.

Notes:

1- console output is attached. I cant grab logs. nothing is saved
in /var/log. so I just got a big pic, sorry. I miss a few lines
from the beginning, but I think all are repeating "Dead loop on
virtual device tap0 ...". the end of the log is the end of
messages showed on the screen.

2- I tried both 2.6.35 and 38 on ubuntu 10.10 and 11.04
receptively

3- OVS is 1.2.2 and click is from the git (kohler-click-81e0196).

4- the same config works fine in usermode

5- I tested the same scenario on OVS without click: eth0 > OVS
> tap1. it works.

6- pls let me know if I can do further testing or better logging.

any help please?

Hamid

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https://amsterdam.lcs.mit.edu/mailman/listinfo/click