1272019 - Can get into a situation where slow-script notification bar cannot stop script

Status: RESOLVED WORKSFORME

(Core :: DOM: Content Processes, defect, P3)

Description

[Mike Conley (:mconley) (:⚙️)]

STR:

0) Ensure e10s is enabled by default.
1) Enable tracking protection for all sites.
2) Brace yourself, because this next step is going to kill your browser
3) Visit http://www.healthline.com/health/food-nutrition/is-silicon-dioxide-in-supplements-safe
4) Scroll down a bit
5) Wait for the slow-script notification bar to appear.
6) Click on "Stop It"

ER:

The page should become responsive again because I stopped the script.

AR:

The page continues to spin and consume more and more memory. The notification bar will continue to appear every few seconds, despite me clicking "Stop It" every time.

Comment 1

[Bill McCloskey [inactive unless it's an emergency] (:billm)]

What happens in non-e10s? It's pretty easy for a page to defeat the slow script killer since we only shut down one script. Example:

setInterval(function { ... do something that takes 10 seconds ...}, 0);

Comment 2

[Kyle Huey (Exited; not receiving bugmail, old account, do not use)]

(In reply to Bill McCloskey (:billm) from comment #1)
> What happens in non-e10s? It's pretty easy for a page to defeat the slow
> script killer since we only shut down one script. Example:
> 
> setInterval(function { ... do something that takes 10 seconds ...}, 0);

While it's still not difficult, I did fix that specific case in Bug 1252268.

Comment 3

[Jens Stutte [:jstutte]]

I scrolled down to the end without any delays or janks.