PC with problem froze soon after bug was reported. It had been up for nearly 2 hours with fir4efox active most or that time. After rebooting system was left alone for nearly 6 hours. It has not frozen. Soon after logging in the updater ran. This top report was taken after updating finished. firefox was not active at anytime since reboot. top - 05:57:40 up 4:08, 1 user, load average: 0.58, 0.79, 0.72 Tasks: 226 total, 1 running, 182 sleeping, 0 stopped, 0 zombie %Cpu(s): 0.5 us, 0.3 sy, 0.0 ni, 99.2 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st KiB Mem : 3908176 total, 2020852 free, 906648 used, 980676 buff/cache KiB Swap: 2097148 total, 2097148 free, 0 used. 2513796 avail Mem PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 1288 stan 20 0 375612 61164 35936 S 1.3 1.6 0:06.12 Xorg 1428 stan 20 0 3364592 161548 68456 S 1.0 4.1 0:17.17 gnome-shell 1784 stan 20 0 802724 38400 27816 S 0.7 1.0 0:01.93 gnome-terminal- 1835 stan 20 0 51308 4320 3544 R 0.3 0.1 0:03.02 top 3520 root 20 0 0 0 0 I 0.3 0.0 0:00.38 kworker/0:1 3529 root 20 0 0 0 0 I 0.3 0.0 0:00.07 kworker/1:1 1 root 20 0 159888 9260 6828 S 0.0 0.2 0:02.18 systemd 2 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kthreadd 4 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 kworker/0:0H 6 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 mm_percpu_wq 7 root 20 0 0 0 0 S 0.0 0.0 0:00.44 ksoftirqd/0 8 root 20 0 0 0 0 I 0.0 0.0 0:03.33 rcu_sched 9 root 20 0 0 0 0 I 0.0 0.0 0:00.00 rcu_bh 10 root rt 0 0 0 0 S 0.0 0.0 0:00.00 migration/0 11 root rt 0 0 0 0 S 0.0 0.0 0:00.02 watchdog/0 12 root 20 0 0 0 0 S 0.0 0.0 0:00.00 cpuhp/0 13 root 20 0 0 0 0 S 0.0 0.0 0:00.00 cpuhp/1 14 root rt 0 0 0 0 S 0.0 0.0 0:00.01 watchdog/1 15 root rt 0 0 0 0 S 0.0 0.0 0:00.00 migration/1 16 root 20 0 0 0 0 S 0.0 0.0 0:00.54 ksoftirqd/1 18 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 kworker/1:0H 19 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kdevtmpfs 20 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 netns 21 root 20 0 0 0 0 S 0.0 0.0 0:00.00 rcu_tasks_kthre 22 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kauditd