1300394 - Website runs with 100% CPU in Firefox without showing a slow script warning

Status: RESOLVED INVALID

(Core :: JavaScript Engine, defect, P3)

Description

[Stefano]

Attachment: FF_Freeze.png

User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:48.0) Gecko/20100101 Firefox/48.0
Build ID: 20160728203720

Steps to reproduce:

Visit following Website:
http://www.dinomage.com/2013/01/howto-sdl-on-android/

Scrolling with the mouse wheel is OK, but if you scroll by clicking on the scrollbar, FF freezes.
E10S is activated.


Actual results:

FF freezes.

Comment 1

[Stefano]

Attachment: ff_support.txt

Comment 2

[Alice0775 White]

I can also reproduce the problem on Chrome Dev54 as well as Nightly51.0a1 Windows10.

Comment 3

[Mats Palmgren (inactive)]

> I can also reproduce the problem on Chrome Dev54

Seems like a bug in the web page then.  If I run Firefox in a debugger
and look at the stack I see a lot of string allocations and GC.
The web content process runs with 100% CPU, memory usage increasing
steadily.

There's no "slow script" dialog though, which I guess is a bug.
Reassigning to JS to triage that bit.  Other than that, this is
for Tech Evang.

Comment 4

[Tom Kloos]

I agree that the web page in question appears broken using:
Build identifier: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:50.0) Gecko/20100101 Firefox/50.0
Id: 20160828004009

This Aurora version of Firefox DOES pop up "web page slowing down browser" and allows it to be stopped after about 12 seconds.

Comment 5

[Virtual_ManPL [:Virtual] 🇵🇱 - (please needinfo? me - so I will see your comment/reply/question/etc.)]

In about 10s I get unresponsive script warning on Firefox Nightly 51.0a1 (2016-09-04) [64bit] on Windows 7 [64bit].

Comment 6

[Stefano]

I wasn't sure, if this was a bug in Firefox or in the website. When Chrome has the same issue, then this bug report can be closed, because I get a unresponsive script warning, too from FF.

Comment 7

[Virtual_ManPL [:Virtual] 🇵🇱 - (please needinfo? me - so I will see your comment/reply/question/etc.)]

So marking as WORKSFORME as unresponsive script warning (e10s disabled and on enabled too).

@ Mats Palmgren (:mats) - if you still don't get unresponsive script warning please reopen this bug.

Comment 8

[Mats Palmgren (inactive)]

Nightly 51.0a1 (2016-09-04) on 64-bit Linux using a fresh profile.
I left it running for ~5 minutes on the URL (at 100% CPU the entire time).
There was no slow script warning presented.

(I spawned off Tech Evang bug 1300542 to notify the site.)

Comment 9

[Stefano]

This bug can't be reproduced anymore. Maybe, because the website is fixed.