No cleanup of ppp0 device in 2.2.11

Thomas Speck (Thomas.Speck@univ-rennes1.fr)
Wed, 1 Sep 1999 22:59:43 +0200 (CEST)

Hi !
I noticed, that after shutting down a ppp-connection ppp0 device is still
accessible and one can manipulate it. This causes problems with access of
the same ttyS* device later on. Here is a detailed description of the
problem:

Well, before any ppp connection:
ThS_home:[~]# ifconfig ppp0
ppp0: error fetching interface information: Device not found

OK, now I establsh ppp connection.

ThS_home:[~]# ifconfig ppp0
ppp0 Link encap:Point-to-Point Protocol
inet addr:129.20.129.72 P-t-P:129.20.129.70 Mask:255.255.255.255
UP POINTOPOINT RUNNING NOARP MULTICAST MTU:542 Metric:1
RX packets:6198 errors:55 dropped:0 overruns:0 frame:55
TX packets:3674 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:10

So, after shutting down ppp-connection now ...

ThS_home:[~]# ifconfig ppp0
ppp0 Link encap:Point-to-Point Protocol
inet addr:129.20.129.72 P-t-P:129.20.129.70 Mask:255.255.255.255
POINTOPOINT NOARP MULTICAST MTU:1500 Metric:1
RX packets:7417 errors:62 dropped:0 overruns:0 frame:62
TX packets:4342 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:10

So, device isn't cleaned up. In addition one can now still ping to this
address and one can change it with ifconfig.

Since I am using an external modem I disconnect the it now physically
and attach a null modem cable on the same port with a serial terminal
on the other end and type the
following:

ThS_home:[~]# echo "send me" > /dev/modem

This results in an endless loop and nothing is received on the terminal.
Interestingly there is no process beeing showed by ps.

hitting control-c gives:
bash: /dev/modem: Interrupted system call

Unfortunately, I don't known too much about kernel hacking to say that
these two things are actually directly related, however they depend on
each other and are reproducable.

If you can't reproduce this on your boxes or want me to do further tests,
etc. please let me know. 

--
Thomas












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