Bug 57729 – Minimalistic QT / webkit application crashes often for facebook applications.

• Component: JavaScriptCore
• Status: RESOLVED WONTFIX

Created attachment 88014 [details]
Simplistic Qt browser showing the bug

I do not know which webkit version exactly I am using.

I was forwarded by QT, where I initially filed a bug under following URL:
http://bugreports.qt.nokia.com/browse/QTBUG-18390

Problem was observed on a linux host Qt 4.7.2 and on a Qt 4.7. windows host


I created a minimalistic web browser (code attached),
which tries to open the url of a facebook application.

The code hard codes the url of one specific facebook application,
but I could reproduce the bug also with other facebook apps.

How to reproduce the bug:

start the application:

After starting the script a login screen shows up

(email address and password field in the top right corner of the display)
One can also see for a short time some web elements of the facebook application one wants to log in

after a few seconds the layout changes and the email address and
password field are in the middle of the screen

I enter valid email address and password of an existing facebook account and click on
connect.

Sometimes the application segfaults.

I discovered the problem first with PyQt (where the error seems to occur a little more often), but the C++ applications fails as well.

I did also attach the backtrace of the segfaulted application

Created attachment 88015 [details]
QT project file for test case

Created attachment 88016 [details]
back trace of crashed application

Created attachment 88017 [details]
PyQT example provoking the same bug

Created attachment 88018 [details]
related QT bug report

[Aparna Nandyal]

Unable to reproduce this problem with latest code from trunk on Linux platform. How frequent is the crash? I have tried about 8 times.

(In reply to comment #5)
> Unable to reproduce this problem with latest code from trunk on Linux platform. How frequent is the crash? I have tried about 8 times.

This is strange it might be, that Facebook changed their contents.
With the description given in this bug report I tried 7 times and could not make it crash. normally it crashed every two to four times.

On the other hand I could crash the same unmodified example code 7 times out of 7 attempts with a slightly modified sequence.


The slightly modified sequence is:

1.) start the application
2.) wait a few seconds (till the login form is displayed in the middle of the screen.
2,) enter emailaddress and password.
3,) wait till the facebook application shows up.
4.) Move the mouse from the top left of the screen to the right until you see the mouse over text 'messages' 
5.) click now on messages. You should now see the messages tear-down menu
6.) click on the bottom of this menu on 'See All Messages'
7.) shortly after the application should segfault

So far this is 100% reproducable with my version of Qt / Webkit.

Could you please tell me how I can determine the webkit version used by my qt library / PyQT setup? Ar there any functions / header file constants indicating the version?

There's a new comment on http://bugreports.qt.nokia.com/browse/QTBUG-18390
about another way of reproducing the bug.

Use attachment "Simplistic Qt browser showing the bug" of this bug report 
and change the url from
"http://apps.facebook.com/be-heroic"
to
"http://facebook.com"


recompile and start the application

l1.) ogin with valid email / password
2.) click on "Home" on the top right of the web page.

I tried it twice, it crashed twice.

[Ahmad Saleem]

Qt toolkit support is removed. I think this can be marked as "RESOLVED WONTFIX". Thanks!