Bug 154073

Summary:	unregister_netdevice: waiting for modemB to become free. Usage count = 1
Product:	[openSUSE] openSUSE 10.3	Reporter:	Forgotten User ZhJd0F0L3x <forgotten_ZhJd0F0L3x>
Component:	Kernel	Assignee:	Karsten Keil <karsten.keil>
Status:	RESOLVED WORKSFORME	QA Contact:	E-mail List <qa-bugs>
Severity:	Normal
Priority:	P5 - None
Version:	RC 2
Target Milestone:	---
Hardware:	Other
OS:	Other
Whiteboard:
Found By:	Component Test	Services Priority:
Business Priority:		Blocker:	---
Marketing QA Status:	---	IT Deployment:	---
Bug Depends on:
Bug Blocks:	140732
Attachments:	/var/log/messages, including sysrq-t "ps auxwww" ifcfg-modemB ifcfg-modemK (Kabel) ifcfg-modemU wlan LAN /var/log/messages excerpt, including the events leading up to the problem and a sysrq-t

Description Forgotten User ZhJd0F0L3x 2006-02-28 10:36:05 UTC

seife@susi:/tmp> uname -r
2.6.16-rc4-git2-20060222144057-default

Following situation:
- dialled in via bluetooth-rfcomm-ppp
- RAS active
- stop the ppp interface, ras gets killed from ip-down.d/ script.
- plug the machine into the suse network
- try to switch profiles with scpm
- network setup hangs, all "ifconfig" or "ip show" hang in state D
Log is constantly filled with "unregister_netdevice: waiting for modemB to become free. Usage count = 1"

I'll attach sysrq-T and "ps auxwww"

Comment 1 Forgotten User ZhJd0F0L3x 2006-02-28 10:36:51 UTC

Created attachment 70598 [details]
/var/log/messages, including sysrq-t

Comment 2 Forgotten User ZhJd0F0L3x 2006-02-28 10:38:09 UTC

Created attachment 70599 [details]
"ps auxwww"

Note that i had to reboot to get the machine running again.
And no, i have not seen something like that since ~suse 9.1, so it is probably not easily reproducible :-)

Comment 3 Karsten Keil 2006-02-28 11:05:02 UTC

Can you try to reproduce it ?
modemB (why modemB ?) is the ppp device I guess, please provide all ifcfg-* files.

Comment 4 Forgotten User ZhJd0F0L3x 2006-02-28 11:43:36 UTC

(In reply to comment #3)
> Can you try to reproduce it ?

give me a testcace :-)

> modemB (why modemB ?) is the ppp device I guess, please provide all ifcfg-*
> files.

modemB == bluetooth. Easier to remember "modemB", "modemU" etc instead of modem0, modem1, ...

I will attach them all.

Comment 5 Forgotten User ZhJd0F0L3x 2006-02-28 11:44:10 UTC

Created attachment 70608 [details]
ifcfg-modemB

Comment 6 Forgotten User ZhJd0F0L3x 2006-02-28 11:44:42 UTC

Created attachment 70609 [details]
ifcfg-modemK (Kabel)

Comment 7 Forgotten User ZhJd0F0L3x 2006-02-28 11:45:20 UTC

Created attachment 70610 [details]
ifcfg-modemU

Comment 8 Forgotten User ZhJd0F0L3x 2006-02-28 11:45:44 UTC

Created attachment 70611 [details]
wlan

Comment 9 Forgotten User ZhJd0F0L3x 2006-02-28 11:46:04 UTC

Created attachment 70612 [details]
LAN

Comment 10 Karsten Keil 2006-02-28 11:49:45 UTC

So "give me a testcace" means, you already tried several times to do the same as you describe in "Following situation" with Beta5 with out hitting this problem ?

Comment 11 Forgotten User ZhJd0F0L3x 2006-02-28 11:55:29 UTC

yes. I use dialin and RAS every day and i think (from the ps output) that it already hung when killing rasconnect, before plugging into the suse network.
And i have not seen those "waiting for ... to become free" for a long time.

Comment 12 Karsten Keil 2006-03-13 12:21:48 UTC

It maybe related to this mainline bug report:
http://bugzilla.kernel.org/show_bug.cgi?id=6197

The mainline report is about pppoe, but maybe other ppp addons have the same problem. I'll monitor this bug and the ongoing discussion on netdevel.

Comment 15 Karsten Keil 2007-02-22 18:25:44 UTC

I did not saw any of these problems with newer version, so I think it was solved. If the problem still exist, please reopen it.

Comment 16 Forgotten User ZhJd0F0L3x 2007-09-27 09:41:19 UTC

Still happened today.

What i did:
- At home, i was in the local LAN via interface "cable" (e1000) or "air" (ipw2200)
- While in the LAN, i dialled into the 3G network via a option data card (pppd), default route pointed to the dialup
- started VPN (rasconnect.pl)
- moved from home to office, ppp connection still alive, WLAN probably disconnected
- plugged machine into the office LAN
- called "scpm switch", to switch the networking setup for the office
  - scpm switch restarts networking
  - this includes stopping smpppd, which did not stop the active pppd.
    (no smpppd enabled in the office profile)
- i noticed pppd was still active, so i simply pulled the card out while the scpm switch was running (i thought that the default route pointing to dialup would be a problem, so i wanted to get rid of it).

Now i got the infamous "kernel: unregister_netdevice: waiting for modemX to become free. Usage count = 1" message and all i could do was reboot. Everything that was trying to access /proc/net/ was apparently hanging, also "ifconfig" and "ip".

I did a sysrq-T trace which i will attach.

This is with 10.3RC2

Comment 17 Forgotten User ZhJd0F0L3x 2007-09-27 09:45:18 UTC

Created attachment 175085 [details]
/var/log/messages excerpt, including the events leading up to the problem and a sysrq-t

Comment 18 Karsten Keil 2008-06-08 13:59:31 UTC

Newer kernel did resolve some network usage bugs so I hope that this is resolved with 11.0. If you run into this again with 11.0, please open a new bug.