Hi LaM,
our server was up-to-date with kernel: 3.19.0-56-generic, when We start to notice this bug
For us was necessary to downgrade to linux-image-3.19.0-43-generic:
Our procedure was:
-- Check kernel running = uname -r
-- Check the firmware installed with = dpkg --list | grep linux-image
-- Check file present in the partition = /boot/
-- Install the old firmware = apt-get install linux-image-3.19.0-43-generic
-- Check all firmware installed again = dpkg --list | grep linux-image
-- Modify grab = /etc/default/grub
# GRUB_DEFAULT=0
GRUB_DEFAULT="Advanced options for Ubuntu>Ubuntu, with Linux 3.19.0-43-generic"
-- Reboot
-- Check kernel running = uname -r
Since then Samba and server are running smooth