I found package which is the source of the problem!
Problem appears after upgrading network-manager package 0.9.4.0-0ubuntu4.2 to 0.9.4.0-0ubuntu4.3
So it seems to be not kernel bug, but it is a bug of the network-manager!
Next step is to find out which changes were made to the network-manager package!
I found package which is the source of the problem!
Problem appears after upgrading network-manager package 0.9.4.0-0ubuntu4.2 to 0.9.4.0-0ubuntu4.3
So it seems to be not kernel bug, but it is a bug of the network-manager!
Next step is to find out which changes were made to the network-manager package!