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List:       kde-frameworks-devel
Subject:    Re: Review Request 118639: KCMultiDialog: Fix crash when clicking OK
From:       Aurélien Gâteau <agateau () kde ! org>
Date:       2014-06-13 7:42:54
Message-ID: 20140613074254.16370.43499 () probe ! kde ! org
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> On June 12, 2014, 7:23 p.m., Aleix Pol Gonzalez wrote:
> > Would it make sense to backport that change to kdelibs4?

Just looked at kdelibs4 code: the bug cannot happen there because finished() is \
always emitted after okClicked(). (in kdelibs4 all of those were handled by KDialog)


- Aurélien


-----------------------------------------------------------
This is an automatically generated e-mail. To reply, visit:
https://git.reviewboard.kde.org/r/118639/#review59889
-----------------------------------------------------------


On June 13, 2014, 9:41 a.m., Aurélien Gâteau wrote:
> 
> -----------------------------------------------------------
> This is an automatically generated e-mail. To reply, visit:
> https://git.reviewboard.kde.org/r/118639/
> -----------------------------------------------------------
> 
> (Updated June 13, 2014, 9:41 a.m.)
> 
> 
> Review request for KDE Frameworks.
> 
> 
> Bugs: 334624
> https://bugs.kde.org/show_bug.cgi?id=334624
> 
> 
> Repository: kcmutils
> 
> 
> Description
> -------
> 
> When one closes KCMultiDialog with OK, QDialog::finished() can be emitted before \
> the clicked() signal of the OK button. This causes the following sequence to \
> happen: 
> - KCMultiDialogPrivate::_k_dialogClosed
> * deletes the KCModule
> - KCModuleProxyPrivate::_k_moduleDestroyed
> * sets kcm to 0
> 
> - KCMultiDialog::slotOkClicked
> - KCMultiDialogPrivate::apply
> - KCModuleProxy::save
> - KCModuleProxyPrivate::realModule
> * notices kcm is 0, so recreates it
> * calls kcm->save()
> - KWinDesktopConfig::save()
> * crashes because it expects kcm->load() to have been called
> 
> To avoid this, trigger the cleanup code in closeEvent() rather than when finished() \
> is emitted, as we can be sure closeEvent() is always called *after* the methods \
> connected to the button box signals has executed. 
> 
> Diffs
> -----
> 
> src/kcmultidialog.h 72e45a5 
> src/kcmultidialog.cpp 478c25a 
> 
> Diff: https://git.reviewboard.kde.org/r/118639/diff/
> 
> 
> Testing
> -------
> 
> Configuring virtual desktops does not crash anymore
> 
> 
> Thanks,
> 
> Aurélien Gâteau
> 
> 


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      This is an automatically generated e-mail. To reply, visit:
      <a href="https://git.reviewboard.kde.org/r/118639/">https://git.reviewboard.kde.org/r/118639/</a>
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<blockquote style="margin-left: 1em; border-left: 2px solid #d0d0d0; padding-left: \
10px;">  <p style="margin-top: 0;">On June 12th, 2014, 7:23 p.m. CEST, <b>Aleix Pol \
Gonzalez</b> wrote:</p>  <blockquote style="margin-left: 1em; border-left: 2px solid \
#d0d0d0; padding-left: 10px;">  <pre style="white-space: pre-wrap; white-space: \
-moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: \
break-word;">Would it make sense to backport that change to kdelibs4?</pre>  \
</blockquote>







</blockquote>

<pre style="white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: \
-pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">Just looked at kdelibs4 \
code: the bug cannot happen there because finished() is always emitted after \
okClicked(). (in kdelibs4 all of those were handled by KDialog)</pre> <br />










<p>- Aurélien</p>


<br />
<p>On June 13th, 2014, 9:41 a.m. CEST, Aurélien Gâteau wrote:</p>








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<div>Review request for KDE Frameworks.</div>
<div>By Aurélien Gâteau.</div>


<p style="color: grey;"><i>Updated June 13, 2014, 9:41 a.m.</i></p>







<div style="margin-top: 1.5em;">
 <b style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Bugs: </b>


 <a href="https://bugs.kde.org/show_bug.cgi?id=334624">334624</a>


</div>



<div style="margin-top: 1.5em;">
 <b style="color: #575012; font-size: 10pt;">Repository: </b>
kcmutils
</div>


<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Description </h1>
 <table width="100%" bgcolor="#ffffff" cellspacing="0" cellpadding="10" \
style="border: 1px solid #b8b5a0">  <tr>
  <td>
   <pre style="margin: 0; padding: 0; white-space: pre-wrap; white-space: \
-moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: \
break-word;">When one closes KCMultiDialog with OK, QDialog::finished() can be \
emitted before the clicked() signal of the OK button. This causes the following \
sequence to happen:

- KCMultiDialogPrivate::_k_dialogClosed
  * deletes the KCModule
    - KCModuleProxyPrivate::_k_moduleDestroyed
      * sets kcm to 0

- KCMultiDialog::slotOkClicked
  - KCMultiDialogPrivate::apply
    - KCModuleProxy::save
      - KCModuleProxyPrivate::realModule
        * notices kcm is 0, so recreates it
        * calls kcm-&gt;save()
          - KWinDesktopConfig::save()
            * crashes because it expects kcm-&gt;load() to have been called

To avoid this, trigger the cleanup code in closeEvent() rather than when finished() \
is emitted, as we can be sure closeEvent() is always called *after* the methods \
connected to the button box signals has executed.


</pre>
  </td>
 </tr>
</table>


<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Testing </h1>
<table width="100%" bgcolor="#ffffff" cellspacing="0" cellpadding="10" style="border: \
1px solid #b8b5a0">  <tr>
  <td>
   <pre style="margin: 0; padding: 0; white-space: pre-wrap; white-space: \
-moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: \
break-word;">Configuring virtual desktops does not crash anymore</pre>  </td>
 </tr>
</table>


<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Diffs</b> </h1>
<ul style="margin-left: 3em; padding-left: 0;">

 <li>src/kcmultidialog.h <span style="color: grey">(72e45a5)</span></li>

 <li>src/kcmultidialog.cpp <span style="color: grey">(478c25a)</span></li>

</ul>

<p><a href="https://git.reviewboard.kde.org/r/118639/diff/" style="margin-left: \
3em;">View Diff</a></p>







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