I am experiencing the same Firefox (53.0.2) behavior as well, on three occasions now. I was then able to get a few lines from /var/log/kern.log before the whole laptop got unresponsive and I had to switch it off with the power button.
I am experiencing the same Firefox (53.0.2) behavior as well, on three occasions now. I was then able to get a few lines from /var/log/kern.log before the whole laptop got unresponsive and I had to switch it off with the power button.