I've send a mail about this to the xorg-devel list to discuss this further, as said already I believe this ultimately is a Qt/KDe bug, but lets see where the discussion goes first.

Please try to run the kde application with
--graphicssystem native

e.g: kcalc --graphicssystem native

The native graphicssystem might bypass the shm extension.

It works, thanks!

This is affecting some non-KDE apps that are fairly significant, I think (thanks Andrew):

https://bugzilla.redhat.com/show_bug.cgi?id=1212180 - liveusb-creator
https://bugzilla.redhat.com/show_bug.cgi?id=1196237 - hplip (HP printer utilities)

*** Bug 1212180 has been marked as a duplicate of this bug. ***

Hi Adam,

(In reply to awilliam from comment #4)
> This is affecting some non-KDE apps that are fairly significant, I think
> (thanks Andrew):
> 
> https://bugzilla.redhat.com/show_bug.cgi?id=1212180 - liveusb-creator
> https://bugzilla.redhat.com/show_bug.cgi?id=1196237 - hplip (HP printer
> utilities)

I'm afraid that there is nothing which we can do about this from the Xorg side, this is really an apllication side bug, specifically the application / toolkit is not doing proper error checking of the MIT SHM extension related X calls. And more in general people should really not be running gui apps as root (I realize this is sometimes easiest, but at least we should not ship anything setup this way ootb).

Since this really is an application bug I'll add a comment to the bugs in question and re-open them where necessary.

Note I've also discussed this with the some qt people and it is fixed in qt5, and currently there are no plans to fix this for qt4, there answer to this problem is: Do not run gui apps as root.

Regards,

Hans

As this affects multiple Qt apps - at least, liveusb-creator and hp-plugin - should we figure it's a Qt bug?

oh, never mind, just saw the end of c6.