2013/3/7 Richard Genoud [off-list ref]:

2013/3/6 Haiyang Zhang [off-list ref]:

quoted

I have found a simple way to reproduce this kind of warning:
1) reboot the VM (because this warning can be displayed only once.)
2) login to the host and open the VM [Settings]
3) Temporarily change the Network adapter's option [Virtual Switch] to "Not connected".
4) run dmesg, you should see the warning.

The reason for the warning is -- netif_tx_disable() is called when the NIC
is disconnected. And it's called within irq context. netif_tx_disable()
calls local_bh_enable() which displays warning if in irq.

The fix is to remove the unnecessary netif_tx_disable() in the netvsc_linkstatus_callback().
I attached a patch. Would you like to test it on your side as well?

I installed the patched kernel today.
here are the stats of the warings until today :
kern.log.1:Mar 12 22:32:10 devlabo kernel: [30114.506299]
------------[ cut here ]------------
kern.log.2:Mar  5 22:30:48 devlabo kernel: [10455.098586]
------------[ cut here ]------------
kern.log.2:Mar  6 22:31:25 devlabo kernel: [85552.645480]
------------[ cut here ]------------
kern.log.3:Feb 26 22:35:14 devlabo kernel: [37398.788119]
------------[ cut here ]------------
kern.log.3:Feb 27 22:34:37 devlabo kernel: [10688.187196]
------------[ cut here ]------------
kern.log.4:Feb 22 22:32:22 devlabo kernel: [40399.795364]
------------[ cut here ]------------

So, I'll wait for one or two weeks before sending some feedback.

Regards,
Richard