not much of a showstopper
Since I switched to Fedora on my laptop I don't recompile my kernel anymore, and let the distro do it. However, memory prompted me to check out an old hppa server running 2.6.28 and Gentoo; there's an option in there (Security options) to configure how much "low address space to protect from user allocation":
This is the portion of low virtual memory which should be protected from userspace allocation. Keeping a user from writing to low pages can help reduce the impact of kernel NULL pointer bugs.
Apparently there is even a kernel tunable, so nobody needs to recompile/reboot in the short term - just stick in 4096 or whatever your page size is to /proc/sys/vm/mmap_min_addr and you are gaffer taped until you can afford some scheduled downtime to apply both this default and the real fixes to the offending modules.
No idea when this feature was implemented but I'd say at least a year ago - correct me if I'm wrong. I've had it set since I first saw it as I realised the useful purpose it would serve. Obviously I'm not open to much abuse running a PA-RISC box from the Ark, but the principle applies everywhere.
I would hope that any Linux sysadmin worth their salt would have been using this option for some time. In that dreamworld, the impact of this new 'sensational' bug would be small as no local attacker can place code at address 0 to be executed.