Subject: Re: 2.6.8-rc4-bk1 problem: unregister_netdevice: waiting for ppp0 to become free. Usage count = 1

From: Nuno Silva <[email-masked]>
Date: Sun, 22 Aug 2004 09:02:02 +0100

David S. Miller wrote:
| On Sun, 22 Aug 2004 03:13:55 +0100
| Nuno Silva <[email-masked]> wrote:
|
|
|>This problem was introduced between 2.6.8-rc2-bk11 and 2.6.8-rc4-bk1 and
|>always happens. Right now I'm testing with 2.6.8.1 with a patch from Mr.
|>Miller -- "cacheline-align qdisc data in qdisc_create()" (attached).
|
|
| Does that patch fix the problem?
|

Hi!

No, but that patch is necessary for me to use QoS at all, or the kernel
oopses.

I was refering to that patch for you to know that's not the same
problem. Sorry for not being 100% clear.

If you want to freeze your networking :-) you can do this:

remove pppd (or adjust the ppp0 interface name later)
# killall pppd

# sleep 10

make a fony connection to 1.1.1.2 using /dev/null
#pppd /dev/null connect /bin/true persist demand 1.1.1.1:1.1.1.2

# sleep 1

add a CBQ root to ppp0 (or ppp1, if you didn't killall and have another
running)
# tc qdisc add dev ppp0 root handle 1: cbq avpkt 1000 bandwidth 10mbit

ping the fony remote:
# ping 1.1.1.2

kill pppd
#killall pppd

Now check dmesg, you should get "unregister_netdevice: waiting for ppp0
to become free. Usage count = 1"

Another remark: In single user mode pppd died and system load is 0. In
initlevel 3, pppd eats all my CPU... Don't know why.

Right now I'm testing 2.6.8.1-ck3 (because of that can't-burn-cdrom
thing and other stuff) so the attached /proc/config.gz is somewhat
non-vanilla, but this happens with 2.6.8-rc4-bk1[*] and above.

[*] this version is "bad" and 2.6.8-rc2-bk11 is "good". Didn't test with
rc3...

As you can see in the .config I'm using the OLD POLICER.

As always, please request more info if you need it! :-)

Regards,
Nuno Silva