Kyle Jamieson: Click: linuxmodule ToDevice initialization

[Eddie Kohler]

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Date: Thu, 16 Aug 2001 01:02:47 -0400
From: Kyle Jamieson <jamieson at MIT.EDU>
Organization: MIT
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To: kohler at aciri.org
Subject: Click: linuxmodule ToDevice initialization
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Hi,

I'm having problems running the linux module version of ToDevice in
2.4.7; I was wondering if you could give me some advice.  I think the
kernel version may be an issue.

What happens is that before ToDevice::initialize ever gets called,
todev_static_initialize runs, calling register_netdevice_notifier,
passing it the address of device_notifier_hook.  Soon after that, linux
calls device_notifier_hook with NETDEV_UP.

It seems that ToDevice::initialize needs to run before that happens,
because initialize sets up an unknown mapping in to_device_map that gets
filled in when linux calls device_notifier_hook.

The effect of all this is that come shutdown time, linux sends a
NETDEV_DOWN to device_notifier_hook which doesn't result in a dev_put,
which causes linux to wait forever for the device to shutdown (in
net/dev/core.c), which causes click to wait forever:

click: Following threads still active, expect a
crash:                          
click:   router thread pid
99                                                

So, I'm not sure if I'm to blame for my router configuration perhaps, or
ToDevice is broken under 2.4.7.  It seems to be like what I described
above is happening in the reverse order that it's supposed to?

Thanks for any help you can give.

Kyle

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