Red Hat Bugzilla – Bug 110121
XFree86 memory permissions not backwards compatible
Last modified: 2007-11-30 17:06:53 EST
Memory permissions not backwards compatible with OEM driver requirements. chatr "hack" was removed post-QU2 and replaced with different patch. PROT_EXEC patch not sufficient for OEM drivers (nvidia-2.4.18.e.31_4431-1.ia64.rpm) that were tested and released by HP. Customer used up2date and experienced unresolvable system breakage when version XFree86-4.1.0-50.EL applied to IPF system. XFree86 seg faults when used with an OEM driver. When chatr (from 4.1.0-46 revision) was applied to executable, functionality returned to package when using graphics package described. Additional behavior seems to be that before this memory attribute was changed, X server did not properly export symbols to the OEM driver, either.
While we would not make any change to XFree86 or the kernel that would knowingly break a 3rd party driver without good cause, and without notifying relevant vendors and partners ahead of time, Red Hat does not test XFree86 with 3rd party video drivers at all, and we do not certify or guarantee XFree86 will work with 3rd party video drivers, and we do not support systems that are running 3rd party drivers, so it is entirely possible that a kernel update or an XFree86 update might cause 3rd party uncertified drivers to break at any time. The chatr hack we had previously was only a quick hack to make the server work properly until the proper and better solution could be found, which is what we have currently. Nvidia's driver may need to be recompiled by Nvidia with the proper bits to ensure PROT_EXEC is used inside the driver appropriately. I don't consider this to be a bug in our XFree86 package, but rather a bug in the proprietary driver.