How do I kill a Firefox process thrashing my computer? 18.04

Question

In short: a Firefox process takes control of Ubuntu 18.04 LTS in my Acer TravelMate P, and it seems there's nothing I can do but to shutdown the computer. This is similar to https://superuser.com/questions/248707/how-do-i-quickly-stop-a-process-that-is-causing-thrashing-due-to-excess-memory however, the main answer didn't work for me (some combination with SysRq), and I prefer not to have a script running like @tobixen suggests there.

Solution

Ctrl-Alt-T opens a terminal emulation window.

ps -ef | grep firefox shows the Firefox processes, or top will show processes, memory use, and CPU use.

kill -9 nnnnn where nnnnn is the PID number of a suspect process stops that process. You can specify multiple PIDs in one command line.

Browsers are susceptible to running Javascript of dubious goodness when you stumble upon a malicious website. Often, the website's creator is time sharing your PC to run mine Bitcoin or such.

Extensions like NoMiner block mining specifically, and other extensions like NoScript go further and block Javascript except when you let it run. Javascript is used so widely, for good and bad, that NoScript and other apps will allow you to open up Javascript for specific websites as needed, and will remember when you opened the door for a particular site.

Comments

[user535733]

"Some combination?" Perhaps you used the wrong combination? Perhaps you did it wrong?

[Beta Ziliani]

I tried several including all possible combination of Ctrl, Alt, SysRq, Shift plus F. None of them worked.

[user535733]

Then how do you know that it's a runaway process instead of a crash?

[Beta Ziliani]

I just experienced it again, and it's definitively not memory swap. But I don't know what it is. Mouse is still moving around, and fans are at top speed.

[Beta Ziliani]

So far, always while surfing in Firefox

[Beta Ziliani]

As said, the problem is the OS becoming unresponsive. Opening a terminal is completely out of the question (either xterm or Ctrl-Alt-Fn).

[K7AAY]

If you like an answer, click on the checkmark above at left to show you accept the answer. Then it's easier to refer other folks with the same issue to it. (The answer dude also gets 10,000 quatloos in gold-pressed latinum, but IRS takes most of it.)