Created attachment 51585 [details] [review]
patch - check module version on every module load
The X server "duplicates" modules by loading them again from the disk.
Since this "duplication" happens on every input device hotplug, possibly weeks after the X server has been started a different module might have been installed by that time (eg. due to upgrading distribution packages) the X server should check the module every time it is loaded to prevent weird issues due to modules compiled for different ABI.
I compiled an X server with the patch and it worked but I have no idea how to test the error paths.
Please send your patch to xorg-devel for review.
An alternative patch that prevents the reload was checked in.