My Ubuntu Server has been connecting to my Server 2012 R2 DFS namespace for about 2 years now with no issues. After the last couple of rounds of updates (Ubuntu and Windows) I noticed that every couple of hours the mount would drop and not come back. Accessing the mount point /mnt/media would just completely freeze the session.

/var/samba/log is empty and there is nothing in the Windows logs of note.

From dmesg:

CIFS VFS: Error -104 sending data on socket to server

Is the only error I can find!

The mount is from FSTAB:

//dfsnamespace/media /mnt/media/ cifs credentials=/etc/samba/user,noserverino  0 0

I'll notice that none of my media will play, I'll come and log into the server and do a 'sudo mount -a' and about 50% of the time it will come back. The other 50% nothing happens and I end up rebooting the server.

If I manually mount with smbclient, no problems!

Anyone have any ideas why:

  1. What's causing this issue in the first place
  2. Why the /var/logs/samba has no logs?

Any help is greatly appreciated!


Looks like this is a bug in the 4.4.0 kernel. Some sort of race condition every 15 minutes causes a flood and disconnect.


I upgraded to 4.9.30 and it appears to have resolved the issues. The steps I followed are:

  1. Download all the Kernel deb's

    wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.9/linux-headers-4.9.0-040900_4.9.0-040900.201612111631_all.deb
    wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.9.30/linux-headers-4.9.30-040930_4.9.30-040930.201705251131_all.deb
    wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.9/linux-headers-4.9.0-040900-generic_4.9.0-040900.201612111631_amd64.deb
  2. Then install with:

    sudo dpkg -i *.deb

Then reboot into the new kernel. Confirm with:

uname -r

Obviously be careful if you have hardware or services deeply dependent on a certain kernel. My server only runs Plex and I was able to update with no ill effects.

Forgive the poor formatting, the 'code' format wasn't working correctly!

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