Comment # 6 on bug 1203539 from John Carrick Smith

Created attachment 861609 [details]
Output from journalctl

I tried using the alt-sysrq-? sequence and it didn't appear to make any
difference.

I tried a second time. 

1. I left it in the 'hung' state for 3 minutes.
2. Pressed ctrl-alt-del, then ctrl-alt-ins, then ctrl-alt-bksp.
3. Then followed the alt-sysrq-? sequence.

There is more data in the attached file than in the previous - I hope it is
what you are looking for.

John