Virtualbox causes a leak in cursors as reported by xrestop

[iwienand]

I am seeing "cursors" as reported by xrestop constanly increasing, which I believe is leading to a leak in X11 which slowly but surely eats up all memory, forcing me to restart.

This has been happening for at least all of the 6.0 branch of virtualbox, but maybe earlier.

After searching, I found a similar comment suggesting the same thing:

https://www.virtualbox.org/ticket/15892?cversion=0&cnum_hist=14#comment:14

I graphed it out over a day or so, and I could see that it was constantly increasing whenever I was using the VM, but remained stable otherwise (graph attached). It never went down.

I've attached a small screenshot video (for whatever reason, it seems gnome screenshot didn't actually capture the cursor... but you can see the link highlighting and the cursors value constantly increasing).

I would note it happens only the cursor switch when *not* in capture mode (i.e., turn off mouse integration and you can switch the cursor as much as you like and it never increases on the host). Maybe for someone skilled in the art that could help pinpoint which library this is related to?

I am currently running 6.0.8 on Fedora 30, but as mentioned it has been happening before that and the original bug was in the 5.1 series.

I've filed ​https://bugzilla.redhat.com/show_bug.cgi?id=1713162 too

[iwienand]

The screencast is slightly too big but you can see it at

​https://bugzilla.redhat.com/attachment.cgi?id=1572300

[Michael Thayer]

Please attach a log file and take a look at these Red Hat and Qt bugs:

• ​https://bugzilla.redhat.com/show_bug.cgi?id=1373451
• ​https://codereview.qt-project.org/c/qt/qtbase/+/170426

[gombara]

It looks like that this is (was) a Qt bug which had been patched. We will apply the patch to the Qt library we distribute. Meanwhile you can test Fedora 30 package instead of "all distributions" package which we guess you have been using.