quoted

create a sysfs entry for netconsole in /sys/class/misc.
This entry has elements related to netconsole as follows.
You can change configuration of netconsole(writable attributes such as IP
address, port number and so on) and check current configuration of netconsole.

-+- /sys/class/misc/
 |-+- netconsole/
   |-+- port1/
   | |--- id          [r--r--r--]  unique port id
   | |--- remove      [-w-------]  if you write something to "remove",
   | |                             this port is removed.
  

IMHO this kind of "magic side effect" is a misuse of sysfs. and would
make proper locking
impossible. How do you deal with the dangling reference to the
netconsole object?

I manage the reference by using a list.
If you write something to "remove", 
firstly the port entry is removed from sysfs and then
the reference is removed from the list and a resource of the port is freed.

f= open (... netconsole/port1/remove")
write(f, "", 1)
sleep(2)
write(f, "", 1) .... this probably would crash...


Maybe having a state variable/sysfs file so you could setup the port and
turn it on/off with write.

You are right.
When I tested above program, my machine crashed.

I'm going to rethink the interface for netconsole.

Thanks for your comments.
-- 
Keiichi KII
NEC Corporation OSS Promotion Center
E-mail: k-keiichi@bx.jp.nec.com