From $URL :
Linux kernel built with support to `tmpfs' is vulnerable to a use-after-free flaw, which happens while remounting tmpfs, which was mounted with mpol=M option initially, but
the same is missing in the remount request.
This flaw could be used to cause kernel crash by unprivileged user, considering a latest commit enables the user to do so.
There are no longer any 2.x or <3.7.10 kernels available in the repository with the exception of sys-kernel/xbox-sources which is unsupported by security.