Bug 989531

Description of problem:

Due to a memory management bug in libchoqok/ui/postwidget.cpp, in certain situations, data of deleted Choqok::UI::Post objects is periodically accessed and dereferenced, which can result in a segmentation fault. The issue has been investigated in <https://bugs.kde.org/show_bug.cgi?id=321307>.

Version-Release number of selected component (if applicable):

choqok-1.3.1-0.2.20130624.fc19
choqok-libs-1.3.1-0.2.20130624.fc19

How reproducible:

Sometimes. (Or always, eventually.)

Steps to Reproduce:

1. Use a PostWidget's "show conversation" button.
2. Wait for the used PostWidget to disappear from the timeline due to age.
3. Wait for UI update.

Actual results:

If unlucky, choqok will crash with a segmentation fault in Choqok::UI::PostWidget::updateUi -> Choqok::UI::PostWidget::formatDateTime. (The probability for a crash increases with time as choqok is dereferencing freed memory every minute from now on.)

Expected results:

No crash.

Additional info:

I have attached a patch against F19-packaged sources which mitigates the problem by adding primitive reference counting to Post/PostWidget relations. This is a quickfix: since choqok apparently never deletes certain PostWidgets, this patch also keeps the associated Posts around and thus increases the footprint of the (already existing) memory leak. I also don't expect the patch to be thread-safe, and in any case it is pretty ugly overall.

As such, I don't expect this patch to be incorporated upstream. However, it fixes the crash and with it user experience. I therefore propose to ship this patch with Fedora until the bug gets fixed properly upstream.

Note that the patch changes libchoqok API and ABI, but according to "repoquery -q --whatrequires `rpm -q --provides choqok-libs | cut -d' ' -f1`" actually only chokoq and choqok-devel depend on choqok-libs.