I also observe regular hangs when I try to shutdown the system (12.04). I have normally mounted several cifs-shares.
I generated a kernel core dump when the computer seemed to hang during shutdown. Among a few remaining userspace processes where S31umountnfs and umount. Looking at umountnfs.sh revealed, that it does not just unmount nfs shares, but all kind of network shares (like cifs, coda, etc).
I suppose the problem is that the interface connected to the share is already down when the script is run, which then leads to blocking shutdown.
As a try to work around this problem, I set "Available to all users" in network manager for the connection in question. On a quick test, this seems to work.
I also observe regular hangs when I try to shutdown the system (12.04). I have normally mounted several cifs-shares.
I generated a kernel core dump when the computer seemed to hang during shutdown. Among a few remaining userspace processes where S31umountnfs and umount. Looking at umountnfs.sh revealed, that it does not just unmount nfs shares, but all kind of network shares (like cifs, coda, etc).
I suppose the problem is that the interface connected to the share is already down when the script is run, which then leads to blocking shutdown.
As a try to work around this problem, I set "Available to all users" in network manager for the connection in question. On a quick test, this seems to work.