Fedora27 freezes after two hours of watching youtube

edit

I have recently updated my old Lenovo T520i from 32-bit F25 to 64-bit F27 and the system started freezing when actively used for a couple of hours. "Actively used" means Firefox with 10-20 tabs, some with YouTube opened, Skype and a couple of terminals.

Symptoms:

• nothing works, the screen is frozen. Mouse is not moving, keyboard not responding, Ctrl-Alt-F2 not working.
• mpstat 1 | tee log started previously in xterm keeps writing stuff
• HDD light is on
• I left it overnight in a frozen state. Didn't help: still no reaction, HDD is still (allegedly) active.

System:

• lsusb
• lspci
• dmesg (this one if from the "good" system state)
• Linux host 4.14.8-300.fc27.x86_64 #1 SMP Wed Dec 20 19:00:18 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

The Story:

A more or less reliable way to reproduce it is to open Firefox with a bunch of tabs (10-20) and start a long Youtube video. After 1-2 hours the freeze happens.

The first time it has frozen I've looked at journalctl and found rt-kit daemon complaining about canary thread suffocating. I thought that setting realtime-scheduling = no in /etc/pulse/daemon.conf might help. But it didn't.

The next time it has frozen at 02:25am (according to the time I saw on the screen in the morning).

• journalctl

mpstat 1:

00:56:31     CPU    %usr   %nice    %sys %iowait    %irq   %soft  %steal  %guest  %gnice   %idle
...
02:25:20     all   17.34    0.25    2.76    1.51    0.50    0.25    0.00    0.00    0.00   77.39
02:25:21     all   15.66    0.00    2.78    1.26    0.51    0.25    0.00    0.00    0.00   79.55
02:25:22     all   18.34    0.25    3.52    0.00    0.50    0.50    0.00    0.00    0.00   76.88
02:25:23     all   31.44    0.00    7.42    7.21    0.44    0.22    0.00    0.00    0.00   53.28
02:25:25     all   12.88    1.01    5.03   59.15    0.40    0.20    0.00    0.00    0.00   21.33
02:25:26     all    5.60    0.00    2.80   91.04    0.28    0.28    0.00    0.00    0.00    0.00
02:25:27     all    5.50    0.00    1.77   92.38    0.18    0.18    0.00    0.00    0.00    0.00
02:25:28     all    5.63    0.00    1.30   92.64    0.00    0.43    0.00    0.00    0.00    0.00
02:25:29     all    1.76    0.00    1.37   96.39    0.20    0.20    0.00    0.00    0.00    0.10
02:25:31     all    1.28    0.00    0.96   97.76    0.00    0.00    0.00    0.00    0.00    0.00
02:25:32     all    1.32    0.00    1.69   96.61    0.19    0.19    0.00    0.00    0.00    0 ...