For quite some time now we have been working on the STOP X64_0x50_win32k!vFreeKernelSectionForUserMapping+22. It's now resolved and the hotfix for it will be released in December, under KB2781406. The stack:
00 fffff880`11b9aa28 fffff960`002382d2 nt!KeBugCheckEx01 fffff880`11b9aa30 fffff960`000c66e0 win32k!vFreeKernelSectionForUserMapping+0x2202 fffff880`11b9aa70 fffff960`000c697c win32k!SURFACE::bDeleteSurface+0x47c03 fffff880`11b9abc0 fffff960`002124bc win32k!bDeleteSurface+0x3404 fffff880`11b9abf0 fffff800`018cc453 win32k!NtGdiEngDeleteSurface+0x5805 fffff880`11b9ac20 000007fe`feeb6f3a nt!KiSystemServiceCopyEnd+0x13
I decided to write on this STOP because through are automated diagnostics system I received dozens of notifications for customers experiencing this problem in memory dumps they uploaded as part of their support case. If you have this problem as well, let me know, or create a support case.
Did you know you can also do some automated diagnosis yourself? You can use Fix it Center Pro (FiCP) or Microsoft Premier Online (MPO). I encourage you to have a look there and see what results you get when uploading your memory dumps there! :)