unregister_netdevice Message. Pi does not respond


5 posts
by Ettore_M » Tue Jan 01, 2013 12:16 pm
Hey guys, I ran into a problem which isn't that much discussed in the forum. Or maybe I didn't find it in the search. So here it is anyway: after some time connected on the net via WiFi on the Pi, something happens, the WiFi disconnects, the CPU is maxxed out and the Pi doesn't respond. The only thing for me to do is to logout from LXDE, but then the only message I get is: unregister_netdevice: waiting for wlan0 to become free. Usage count = 1, which keeps repeating endlessly. At the end, I have to do a hard reset. However, it happens again..

Does anyone know how to resolve this problem? Is it maybe a problem in my /etc/network/interfaces file? Or is it about the OS? I'm using the latest Raspbian image.

Thanks, and Happy New Year!
Hector
Posts: 23
Joined: Sun Apr 08, 2012 10:48 am
by MaxK1 » Tue Jan 01, 2013 1:27 pm
Ugh - I had this problem 5-6 years ago and it was holding up a project. It was only in the case where I was trying to reboot a remote (read: inaccessible) system, so I didn't really care too much _what_ the problem was. It obviously wasn't going away. I was concerned about the system rebooting (don't remember if this was preventing the filesystem from being cleanly shutdown, or just from rebooting)
What I did was a quick 'n dirty hack to the kernel: If it was trying to unregister a device, I let it go through the code once then set the device to 0 so when it went through the 2nd time, the device was free. That solved the problem for my somewhat specific case and I never went back to try to track it down or find a "real" fix for it. That was on a 2.4/2.6 kernel. in net/dev.c I seem to recall - I don't think that code was saved because it was a kludge at best...
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Joined: Sun Aug 26, 2012 11:34 pm
by Ettore_M » Fri Jan 04, 2013 8:03 pm
Until now, the problem seems to be gone with just a simple "sudo apt-get update/upgrade". We 'll see how it goes...
Posts: 23
Joined: Sun Apr 08, 2012 10:48 am
by Ettore_M » Mon Jan 14, 2013 5:23 pm
Happened again some times. I had to do a hard reset several times. If I'm not connected to the internet and USB WiFi is not connected to the Pi, it doesn't happen. Today (after a few days with this problem), it booted ok, I had the chance to "sudo apt-get update/upgrade" and now it's ok again.. Would a SD card reflash fix this problem?

Hector
Posts: 23
Joined: Sun Apr 08, 2012 10:48 am
by MaxK1 » Tue Jan 15, 2013 5:12 pm
It will probably happen again - It seems to be an obscure bug that happens only when something else goes wrong first...
Posts: 478
Joined: Sun Aug 26, 2012 11:34 pm