Yet another ‘lockup’ – this time with 3.18.. So, as the problem also exists with 3.17.x, I have taken the unusual step of reverting to Kernel 3.16.7, for the time being!
Some of the latest correspondence on the issue, here: http://lkml.iu.edu/hypermail/linux/kernel/1412.1/03302.html
Robert Gadsdon. December 12, 2014.